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Journal articles on the topic 'GroESL'

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Published: 7 September 2021

Last updated: 18 February 2022

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Bittner, Alycia N., Amanda Foltz, and Valerie Oke. "Only One of Five groEL Genes Is Required for Viability and Successful Symbiosis in Sinorhizobium meliloti." Journal of Bacteriology 189, no. 5 (2006): 1884–89. http://dx.doi.org/10.1128/jb.01542-06.

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ABSTRACT Many bacterial species contain multiple copies of the genes that encode the chaperone GroEL and its cochaperone, GroES, including all of the fully sequenced root-nodulating bacteria that interact symbiotically with legumes to generate fixed nitrogen. In particular, in Sinorhizobium meliloti there are four groESL operons and one groEL gene. To uncover functional redundancies of these genes during growth and symbiosis, we attempted to construct strains containing all combinations of groEL mutations. Although a double groEL1 groEL2 mutant cannot be constructed, we demonstrate that the quadruple groEL1 groESL3 groEL4 groESL5 and groEL2 groESL3 groEL4 groESL5 mutants are viable. Therefore, like E. coli and other species, S. meliloti requires only one groEL gene for viability, and either groEL1 or groEL2 will suffice. The groEL1 groESL5 double mutant is more severely affected for growth at both 30°C and 40°C than the single mutants, suggesting overlapping functions in stress response. During symbiosis the quadruple groEL2 groESL3 groEL4 groESL5 mutant acts like the wild type, but the quadruple groEL1 groESL3 groEL4 groESL5 mutant acts like the groEL1 single mutant, which cannot fully induce nod gene expression and forms ineffective nodules. Therefore, the only groEL gene required for symbiosis is groEL1. However, we show that the other groE genes are expressed in the nodule at lower levels, suggesting minor roles during symbiosis. Combining our data with other data, we conclude that groESL1 encodes the housekeeping GroEL/GroES chaperone and that groESL5 is specialized for stress response.

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Bittner, Alycia N., and Valerie Oke. "Multiple groESL Operons Are Not Key Targets of RpoH1 and RpoH2 in Sinorhizobium meliloti." Journal of Bacteriology 188, no. 10 (2006): 3507–15. http://dx.doi.org/10.1128/jb.188.10.3507-3515.2006.

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ABSTRACT Among the rhizobia that establish nitrogen-fixing nodules on the roots of host plants, many contain multiple copies of genes encoding the sigma factor RpoH and the chaperone GroEL/GroES. In Sinorhizobium meliloti there are two rpoH genes, four groESL operons, and one groEL gene. rpoH1 mutants are defective for growth at high temperature and form ineffective nodules, rpoH1 rpoH2 double mutants are unable to form nodules, and groESL1 mutants form ineffective nodules. To explore the roles of RpoH1 and RpoH2, we identified mutants that suppress both the growth and nodulation defects. These mutants do not suppress the nitrogen fixation defect. This implies that the functions of RpoH1 during growth and RpoH1/RpoH2 during the initiation of symbiosis are similar but that there is a different function of RpoH1 needed later during symbiosis. We showed that, unlike in Escherichia coli, overexpression of groESL is not sufficient to bypass any of the RpoH defects. Under free-living conditions, we determined that RpoH2 does not control expression of the groE genes, and RpoH1 only controls expression of groESL5. Finally, we completed the series of groE mutants by constructing groESL3 and groEL4 mutants and demonstrated that they do not display symbiotic defects. Therefore, the only groESL operon required by itself for symbiosis is groESL1. Taken together, these results suggest that GroEL/GroES production alone cannot explain the requirements for RpoH1 and RpoH2 in S. meliloti and that there must be other crucial targets.

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Karunakaran, Karuna P., Yasuyuki Noguchi, Timothy D. Read, et al. "Molecular Analysis of the Multiple GroEL Proteins of Chlamydiae." Journal of Bacteriology 185, no. 6 (2003): 1958–66. http://dx.doi.org/10.1128/jb.185.6.1958-1966.2003.

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ABSTRACT Genome sequencing revealed that all six chlamydiae genomes contain three groEL-like genes (groEL1, groEL2, and groEL3). Phylogenetic analysis of groEL1, groEL2, and groEL3 indicates that these genes are likely to have been present in chlamydiae since the beginning of the lineage. Comparison of deduced amino acid sequences of the three groEL genes with those of other organisms showed high homology only for groEL1, although comparison of critical amino acid residues that are required for polypeptide binding of the Escherichia coli chaperonin GroEL revealed substantial conservation in all three chlamydial GroELs. This was further supported by three-dimensional structural predictions. All three genes are expressed constitutively throughout the developmental cycle of Chlamydia trachomatis, although groEL1 is expressed at much higher levels than are groEL2 and groEL3. Transcription of groEL1, but not groEL2 and groEL3, was elevated when HeLa cells infected with C. trachomatis were subjected to heat shock. Western blot analysis with polyclonal antibodies raised against recombinant GroEL1, GroEL2, and GroEL3 demonstrated the presence of the three proteins in C. trachomatis elementary bodies, with GroEL1 being present in the largest amount. Only C. trachomatis groEL1 and groES together complemented a temperature-sensitive E. coli groEL mutant. Complementation did not occur with groEL2 or groEL3 alone or together with groES. The role for each of the three GroELs in the chlamydial developmental cycle and in disease pathogenesis requires further study.

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Chen, Hsiao-Jan, Jui-Chang Tsai, Tsung-Chain Chang, et al. "PCR-RFLP assay for species and subspecies differentiation of the Streptococcus bovis group based on groESL sequences." Journal of Medical Microbiology 57, no. 4 (2008): 432–38. http://dx.doi.org/10.1099/jmm.0.47628-0.

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The sequence diversity of groESL genes among Streptococcus bovis group isolates was analysed, including five reference strains and 36 clinical isolates. Phylogenetic analysis of the groES and groEL sequences showed that the isolates that belonged to the same species or subspecies usually clustered together. The intergenic spacer region between groES and groEL was variable in size (67–342 bp) and sequence and appeared to be a unique marker for species or subspecies determination. Sequence similarities of the groESL genes among species and subspecies ranged from 84.2 to 99.0 % in groES, and from 88.0 to 99.0 % in groEL. Based on the sequences determined, a Streptococcus bovis group-specific PCR assay was developed, which may provide an alternative means of distinguishing the bovis group from other viridans streptococci. Restriction digestion of the amplicon with AclI further differentiated the species and subspecies.

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Gahan, Cormac G. M., James O'Mahony, and Colin Hill. "Characterization of the groESL Operon inListeria monocytogenes: Utilization of Two Reporter Systems (gfp and hly) for Evaluating In Vivo Expression." Infection and Immunity 69, no. 6 (2001): 3924–32. http://dx.doi.org/10.1128/iai.69.6.3924-3932.2001.

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ABSTRACT The ability of intracellular pathogens to sense and adapt to the hostile environment of the host is an important factor governing virulence. We have sequenced the operon encoding the major heat shock proteins GroES and GroEL in the gram-positive food-borne pathogenListeria monocytogenes. The operon has a conserved orientation in the order groES groEL. Upstream ofgroES and in the opposite orientation is a gene encoding a homologue of the Bacillus subtilis protein YdiL, while downstream of groEL is a gene encoding a putative bile hydrolase. We used both reverse transcriptase-PCR (RT-PCR) and transcriptional fusions to the UV-optimized Aequorea victoria green fluorescent protein (GFPUV) to analyze expression of groESL under various environmental stress conditions, including heat shock, ethanol stress, and acid shock, and during infection of J774 mouse macrophage cells. Strains harboring GFPUV transcriptional fusions to the promoter region ofgroESL demonstrated a significant increase in fluorescence following heat shock that was detected by both fluorimetry and fluorescence microscopy. Using both RT-PCR and GFP technology we detected expression of groESL following internalization by J774 cells. Increased intracellular expression of dnaK was also determined using RT-PCR. We have recently described a system which utilizes L. monocytogenes hemolysin as an in vivo reporter of gene expression within the host cell phagosome (C. G. M. Gahan and C. Hill, Mol. Microbiol. 36:498–507, 2000). In this study a strain was constructed in which hemolysin expression was placed under the control of the groESL promoter. In this strain hemolysin expression during infection also confirms transcription from the groESL promoter during J774 and murine infection, albeit at lower levels than the known virulence factorplcA.

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Susin, Michelle F., Humberto R. Perez, Regina L. Baldini, and Suely L. Gomes. "Functional and Structural Analysis of HrcA Repressor Protein from Caulobacter crescentus." Journal of Bacteriology 186, no. 20 (2004): 6759–67. http://dx.doi.org/10.1128/jb.186.20.6759-6767.2004.

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ABSTRACT A large number of bacteria regulate chaperone gene expression during heat shock by the HrcA-CIRCE system, in which the DNA element called CIRCE serves as binding site for the repressor protein HrcA under nonstress conditions. In Caulobacter crescentus, the groESL operon presents a dual type of control. Heat shock induction is controlled by a σ32-dependent promoter and the HrcA-CIRCE system plays a role in regulation of groESL expression under physiological temperatures. To study the activity of HrcA in vitro, we purified a histidine-tagged version of the protein, and specific binding to the CIRCE element was obtained by gel shift assays. The amount of retarded DNA increased significantly in the presence of GroES/GroEL, suggesting that the GroE chaperonin machine modulates HrcA activity. Further evidence of this modulation was obtained using lacZ transcription fusions with the groESL regulatory region in C. crescentus cells, producing different amounts of GroES/GroEL. In addition, we identified the putative DNA-binding domain of HrcA through extensive protein sequence comparison and constructed various HrcA mutant proteins containing single amino acid substitutions in or near this region. In vitro and in vivo experiments with these mutated proteins indicated several amino acids important for repressor activity.

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Tsugawa, Hitoshi, Humie Ito, Miho Ohshima, and Yoshio Okawa. "Cell adherence-promoted activity of Plesiomonas shigelloides GroEL." Journal of Medical Microbiology 56, no. 1 (2007): 23–29. http://dx.doi.org/10.1099/jmm.0.46766-0.

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Previously, it has been demonstrated that the invasion of Caco-2 cells by Plesiomonas shigelloides induces apoptotic cell death. Therefore, the attachment to and colonization of eukaryotic intestinal host cells by P. shigelloides are important steps in causing pathogenicity. In this study, the participation of P. shigelloides GroEL in the attachment of P. shigelloides was examined. The groESL operon of P. shigelloides was isolated by PCR. The nucleotide sequence of the groESL operon of P. shigelloides revealed two ORFs of 294 nucleotides for groES and 1647 nucleotides for groEL. Cell fractionation and immunostaining experiments suggested that the GroEL of P. shigelloides was associated with the bacterial cell surface. The expression of the groEL gene was upregulated during the attachment and apoptosis-induction stages, and the expression of the protein was also induced during the attachment stage. Furthermore, GroEL efficiently promoted the attachment of P. shigelloides to Caco-2 cells, as measured by a FACSCalibur flow cytometer. These results demonstrated that GroEL has a positive influence on the attachment of P. shigelloides to Caco-2 cells.

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Baldini, Regina Lúcia, Marcelo Avedissian, and Suely Lopes Gomes. "The CIRCE Element and Its Putative Repressor Control Cell Cycle Expression of the Caulobacter crescentus groESLOperon." Journal of Bacteriology 180, no. 7 (1998): 1632–41. http://dx.doi.org/10.1128/jb.180.7.1632-1641.1998.

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ABSTRACT The groESL operon is under complex regulation inCaulobacter crescentus. In addition to strong induction after exposure to heat shock, under physiological growth conditions, its expression is subject to cell cycle control. Transcription and translation of the groE genes occur primarily in predivisional cells, with very low levels of expression in stalked cells. The regulatory region of groESL contains both a ς32-like promoter and a CIRCE element. Overexpression ofC. crescentus ς32 gives rise to higher levels of GroEL and increased levels of the groESL transcript coming from the ς32-like promoter. Site-directed mutagenesis in CIRCE has indicated a negative role for thiscis-acting element in the expression of groESLonly at normal growth temperatures, with a minor effect on heat shock induction. Furthermore, groESL-lacZ transcription fusions carrying mutations in CIRCE are no longer cell cycle regulated. Analysis of an hrcA null strain, carrying a disruption in the gene encoding the putative repressor that binds to the CIRCE element, shows constitutive synthesis of GroEL throughout theCaulobacter cell cycle. These results indicate a negative role for the hrcA gene product and the CIRCE element in the temporal control of the groESL operon.

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Kumar, C. M. Santosh, Garima Khare, C. V. Srikanth, Anil K. Tyagi, Abhijit A. Sardesai, and Shekhar C. Mande. "Facilitated Oligomerization of Mycobacterial GroEL: Evidence for Phosphorylation-Mediated Oligomerization." Journal of Bacteriology 191, no. 21 (2009): 6525–38. http://dx.doi.org/10.1128/jb.00652-09.

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ABSTRACT The distinctive feature of the GroES-GroEL chaperonin system in mediating protein folding lies in its ability to exist in a tetradecameric state, form a central cavity, and encapsulate the substrate via the GroES lid. However, recombinant GroELs of Mycobacterium tuberculosis are unable to act as effective molecular chaperones when expressed in Escherichia coli. We demonstrate here that the inability of M. tuberculosis GroEL1 to act as a functional chaperone in E. coli can be alleviated by facilitated oligomerization. The results of directed evolution involving random DNA shuffling of the genes encoding M. tuberculosis GroEL homologues followed by selection for functional entities suggested that the loss of chaperoning ability of the recombinant mycobacterial GroEL1 and GroEL2 in E. coli might be due to their inability to form canonical tetradecamers. This was confirmed by the results of domain-swapping experiments that generated M. tuberculosis-E. coli chimeras bearing mutually exchanged equatorial domains, which revealed that E. coli GroEL loses its chaperonin activity due to alteration of its oligomerization capabilities and vice versa for M. tuberculosis GroEL1. Furthermore, studying the oligomerization status of native GroEL1 from cell lysates of M. tuberculosis revealed that it exists in multiple oligomeric forms, including single-ring and double-ring variants. Immunochemical and mass spectrometric studies of the native M. tuberculosis GroEL1 revealed that the tetradecameric form is phosphorylated on serine-393, while the heptameric form is not, indicating that the switch between the single- and double-ring variants is mediated by phosphorylation.

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Inokuma, Hisashi, Kaori Fujii, Masaru Okuda, et al. "Determination of the Nucleotide Sequences of Heat Shock Operon groESL and the Citrate Synthase Gene (gltA) of Anaplasma (Ehrlichia) platys for Phylogenetic and Diagnostic Studies." Clinical and Vaccine Immunology 9, no. 5 (2002): 1132–36. http://dx.doi.org/10.1128/cdli.9.5.1132-1136.2002.

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ABSTRACT The 1,670-bp nucleotide sequence of the heat shock operon groESL and the 1,236-bp sequence of the citrate synthase gene (gltA) of Anaplasma (Ehrlichia) platys were determined. The topology of the groEL- and gltA-based phylogenetic tree was similar to that derived from 16S rRNA gene analyses with distances. Both groESL- and gltA-based PCRs specific to A. platys were also developed based upon the alignment data.

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Kuchanny-Ardigò, Dorota, and Barbara Lipińska. "Cloning and characterization of the groE heat-shock operon of the marine bacterium Vibrio harveyi." Microbiology 149, no. 6 (2003): 1483–92. http://dx.doi.org/10.1099/mic.0.26273-0.

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The DNA region of the Vibrio harveyi chromosome containing the heat-shock genes groES and groEL was cloned, and the genes were sequenced. These genes are arranged in the chromosome in the order groES–groEL. Northern hybridization experiments with RNA from V. harveyi and a DNA probe carrying both groES and groEL genes showed a single, heat-inducible transcript of approximately 2200 nt, indicating that these genes form an operon. Primer extension analysis revealed a strong, heat-inducible transcription start site 59 nt upstream of groES, preceded by a sequence typical for the Escherichia coli heat-shock promoters recognized by the σ 32 factor, and a weak transcription start site 25 nt upstream the groES gene, preceded by a sequence typical for σ 70 promoters. Transcription from the latter promoter occurred only at low temperatures. The V. harveyi groE operon cloned in a plasmid in E. coli cells was transcribed in a σ 32-dependent manner; the transcript size and the σ 32-dependent transcription start site were as in V. harveyi cells. Comparison of V. harveyi groE transcription regulation with the other well-characterized groE operons of the γ subdivision of proteobacteria (those of E. coli and Pseudomonas aeruginosa) indicates a high conservation of the transcriptional regulatory elements among these bacteria, with two promoters, σ 32 and σ 70, involved in the regulation. The ability of the cloned groESL genes to complement E. coli groE mutants was tested: V. harveyi groES restored a thermoresistant phenotype to groES bacteria and enabled λ phage to grow in the mutant cells. V. harveyi groEL did not abolish thermosensitivity of groEL bacteria but it complemented the groEL mutant with respect to growth of λ phage. The results suggest that the GroEL chaperone may be more species-specific than the GroES co-chaperone.

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Desmond, C., G. F. Fitzgerald, C. Stanton, and R. P. Ross. "Improved Stress Tolerance of GroESL-Overproducing Lactococcus lactis and Probiotic Lactobacillus paracasei NFBC 338." Applied and Environmental Microbiology 70, no. 10 (2004): 5929–36. http://dx.doi.org/10.1128/aem.70.10.5929-5936.2004.

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ABSTRACT The bacterial heat shock response is characterized by the elevated expression of a number of chaperone complexes. Two-dimensional polyacrylamide gel electrophoresis revealed that GroEL expression in probiotic Lactobacillus paracasei NFBC 338 was increased under heat adaptation conditions (52°C for 15 min). Subsequently, the groESL operon of L. paracasei NFBC 338 was PCR amplified, and by using the nisin-inducible expression system, two plasmids, pGRO1 and pGRO2, were constructed on the basis of vectors pNZ8048 and pMSP3535, respectively. These vectors were transferred into Lactococcus lactis(pGRO1) and L. paracasei(pGRO2), and after induction with nisin, overexpressed GroEL represented 15 and 20% of the total cellular protein in each strain, respectively. Following heat shock treatment of lactococci (at 54°C) and lactobacilli (at 60°C), the heat-adapted cultures maintained the highest level of viability (5-log-unit increase, approximately) in each case, while it was found that the GroESL-overproducing strains performed only moderately better (1-log-unit increase) than the controls. On the other hand, the salt tolerance of both GroESL-overproducing strains (in 5 M NaCl) was similar to that of the parent cultures. Interestingly, both strains overproducing GroESL exhibited increased solvent tolerance, most notably, the ability to grow in the presence of butanol (0.5% [vol/vol]) for 5 h, while the viability of the parent strain declined. These results confirm the integral role of GroESL in solvent tolerance, and to a lesser extent, thermotolerance of lactic acid bacteria. Furthermore, this study demonstrates that technologically sensitive cultures, including certain probiotic lactobacilli, can potentially be manipulated to become more robust for survival under harsh conditions, such as food product development and gastrointestinal transit.

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Yeh, Kuo-Chen, Melicent C. Peck, and Sharon R. Long. "Luteolin and GroESL Modulate In Vitro Activity of NodD." Journal of Bacteriology 184, no. 2 (2002): 525–30. http://dx.doi.org/10.1128/jb.184.2.525-530.2002.

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ABSTRACT In the early stages of symbiosis between the soil bacterium Sinorhizobium meliloti and its leguminous host plant, alfalfa, bacterial nodulation (nod) genes are controlled by NodD1, NodD2, and NodD3, members of the LysR family of transcriptional regulators, in response to flavonoid and other inducers released by alfalfa. To gain an understanding of the biochemical aspects of this action, epitope-tagged recombinant NodD1 and NodD3 were overexpressed in Escherichia coli. The DNA binding properties of the purified recombinant NodD proteins were indistinguishable from those of NodD isolated from S. meliloti. In addition, the E. coli GroEL chaperonin copurified with the recombinant NodD proteins. In this study, we showed that NodD proteins are in vitro substrates of the GroESL chaperonin system and that their DNA binding activity is modulated by GroESL. This confirmed the earlier genetic implication that the GroESL chaperonin system is essential for the function of these regulators. Increased DNA binding activity by NodD1 in the presence of luteolin confirmed that NodD1 is involved in recognizing the plant signal during the early stages of symbiosis.

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Walker, D. Carey, Hany S. Girgis, and Todd R. Klaenhammer. "The groESL Chaperone Operon ofLactobacillus johnsonii." Applied and Environmental Microbiology 65, no. 7 (1999): 3033–41. http://dx.doi.org/10.1128/aem.65.7.3033-3041.1999.

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ABSTRACT The Lactobacillus johnsonii VPI 11088groESL operon was localized on the chromosome near the insertion element IS1223. The operon was initially cloned as a series of three overlapping PCR fragments, which were sequenced and used to design primers to amplify the entire operon. The amplified fragment was used as a probe to recover the chromosomal copy of thegroESL operon from a partial library of L. johnsonii VPI 11088 (NCK88) DNA, cloned in the shuttle vector pTRKH2. The 2,253-bp groESL fragment contained three putative open reading frames, two of which encoded the ubiquitous GroES and GroEL chaperone proteins. Analysis of the groESLpromoter region revealed three transcription initiation sites, as well as three sets of inverted repeats (IR) positioned between the transcription and translation start sites. Two of the three IR sets bore significant homology to the CIRCE elements, implicated in negative regulation of the heat shock response in many bacteria. Northern analysis and primer extension revealed that multiple temperature-sensitive promoters preceded the groESLchaperone operon, suggesting that stress protein production in L. johnsonii is strongly regulated. Maximum groESLtranscription activity was observed following a shift to 55°C, and a 15 to 30-min exposure of log-phase cells to this temperature increased the recovery of freeze-thawed L. johnsonii VPI 11088. These results suggest that a brief, preconditioning heat shock can be used to trigger increased chaperone production and provide significant cross-protection from the stresses imposed during the production of frozen culture concentrates.

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Corcoran, B. M., R. P. Ross, G. F. Fitzgerald, P. Dockery, and C. Stanton. "Enhanced Survival of GroESL-Overproducing Lactobacillus paracasei NFBC 338 under Stressful Conditions Induced by Drying." Applied and Environmental Microbiology 72, no. 7 (2006): 5104–7. http://dx.doi.org/10.1128/aem.02626-05.

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ABSTRACT GroESL-overproducing Lactobacillus paracasei NFBC 338 was dried, and its viability was compared with that of controls. Spray- and freeze-dried cultures overproducing GroESL exhibited ∼10-fold and 2-fold better survival, respectively, demonstrating the importance of GroESL in stress tolerance, which can be exploited to enhance the technological performance of sensitive probiotic cultures.

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TOKUNAGA, Masao, Yoichi SHIRAISHI, Masatake ODACHI, et al. "Molecular Cloning of groESL Locus, and Purification and Characterization of Chaperonins, GroEL and GroES, from Bacillus brevis." Bioscience, Biotechnology, and Biochemistry 65, no. 6 (2001): 1379–87. http://dx.doi.org/10.1271/bbb.65.1379.

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Chaurasia, Akhilesh Kumar, and Shree Kumar Apte. "Overexpression of the groESL Operon Enhances the Heat and Salinity Stress Tolerance of the Nitrogen-Fixing Cyanobacterium Anabaena sp. Strain PCC7120." Applied and Environmental Microbiology 75, no. 18 (2009): 6008–12. http://dx.doi.org/10.1128/aem.00838-09.

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ABSTRACT The bicistronic groESL operon, encoding the Hsp60 and Hsp10 chaperonins, was cloned into an integrative expression vector, pFPN, and incorporated at an innocuous site in the Anabaena sp. strain PCC7120 genome. In the recombinant Anabaena strain, the additional groESL operon was expressed from a strong cyanobacterial P psbA1 promoter without hampering the stress-responsive expression of the native groESL operon. The net expression of the two groESL operons promoted better growth, supported the vital activities of nitrogen fixation and photosynthesis at ambient conditions, and enhanced the tolerance of the recombinant Anabaena strain to heat and salinity stresses.

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Chai, Yunrong, and Stephen C. Winans. "The Chaperone GroESL Enhances the Accumulation of Soluble, Active TraR Protein, a Quorum-Sensing Transcription Factor from Agrobacterium tumefaciens." Journal of Bacteriology 191, no. 11 (2009): 3706–11. http://dx.doi.org/10.1128/jb.01434-08.

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ABSTRACT TraR of Agrobacterium tumefaciens is a LuxR-type quorum-sensing transcription factor that regulates genes required for replication and conjugation of the tumor-inducing (Ti) plasmid. TraR requires its cognate autoinducer N-3-oxooctanoyl-homoserine lactone (OOHL) for resistance of proteolysis in wild-type bacteria and for correct protein folding and solubility when overexpressed in E. coli. In this study, we ask whether GroESL might also play a role in TraR folding, as this molecular chaperone assists many proteins in attaining their native tertiary structure. Expression of E. coli GroESL in a strain expressing TraR increases the solubility of TraR and increases transcriptional activity of a TraR-dependent promoter. Both solubility and activity still require OOHL. We also studied the folding of TraR in the closely related bacterium Sinorhizobium meliloti. A mutation in one groEL gene slightly decreased the expression of a TraR-dependent promoter, strongly decreased the accumulation of TraR in Western immunoblot assays, and also strongly influenced the fate of pulse-labeled TraR.

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Mogk, Axel, Andrea Völker, Susanne Engelmann, Michael Hecker, Wolfgang Schumann, and Uwe Völker. "Nonnative Proteins Induce Expression of the Bacillus subtilis CIRCE Regulon." Journal of Bacteriology 180, no. 11 (1998): 2895–900. http://dx.doi.org/10.1128/jb.180.11.2895-2900.1998.

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ABSTRACT The chaperone-encoding groESL and dnaKoperons constitute the CIRCE regulon of Bacillus subtilis. Both operons are under negative control of the repressor protein HrcA, which interacts with the CIRCE operator and whose activity is modulated by the GroESL chaperone machine. In this report, we demonstrate that induction of the CIRCE regulon can also be accomplished by ethanol stress and puromycin. Introduction of the hrcA gene and a transcriptional fusion under the control of the CIRCE operator intoEscherichia coli allowed induction of this fusion by heat shock, ethanol stress, and overproduction of GroESL substrates. The expression level of this hrcA-bgaB fusion inversely correlated with the amount of GroE machinery present in the cells. Therefore, all inducing conditions seem to lead to induction via titration of the GroE chaperonins by the increased level of nonnative proteins formed. Puromycin treatment failed to induce the ςB-dependent general stress regulon, indicating that nonnative proteins in general do not trigger this response. Reconstitution of HrcA-dependent heat shock regulation of B. subtilis in E. coli and complementation of E. coli groESL mutants by B. subtilis groESL indicate that the GroE chaperonin systems of the two bacterial species are functionally exchangeable.

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Schmid, Amy K., Heather A. Howell, John R. Battista, Scott N. Peterson, and Mary E. Lidstrom. "Global Transcriptional and Proteomic Analysis of the Sig1 Heat Shock Regulon of Deinococcus radiodurans." Journal of Bacteriology 187, no. 10 (2005): 3339–51. http://dx.doi.org/10.1128/jb.187.10.3339-3351.2005.

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ABSTRACT The sig1 gene, predicted to encode an extracytoplasmic function-type heat shock sigma factor of Deinococcus radiodurans, has been shown to play a central role in the positive regulation of the heat shock operons groESL and dnaKJ. To determine if Sig1 is required for the regulation of additional heat shock genes, we monitored the global transcriptional and proteomic profiles of a D. radiodurans R1 sig1 mutant and wild-type cells in response to elevated temperature stress. Thirty-one gene products were identified that showed heat shock induction in the wild type but not in the sig1 mutant. Quantitative real-time PCR experiments verified the transcriptional requirement of Sig1 for the heat shock induction of the mRNA of five of these genes—dnaK, groES, DR1314, pspA, and hsp20. hsp20 appears to encode a new member of the small heat shock protein superfamily, DR1314 is predicted to encode a hypothetical protein with no recognizable orthologs, and pspA is predicted to encode a protein involved in maintenance of membrane integrity. Deletion mutation analysis demonstrated the importance in heat shock protection of hsp20 and DR1314. The promoters of dnaKJE, groESL, DR1314, pspA, and hsp20 were mapped and, combined with computer-based pattern searches of the upstream regions of the 26 other Sig1 regulon members, these results suggested that Sig1 might recognize both σ70-type and σW-type promoter consensus sequences. These results expand the D. radiodurans Sig1 heat shock regulon to include 31 potential new members, including not only factors with cytoplasmic functions, such as groES and dnaK, but also those with extracytoplasmic functions, like pspA.

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Tomas, Christopher A., Neil E. Welker, and Eleftherios T. Papoutsakis. "Overexpression of groESL in Clostridium acetobutylicum Results in Increased Solvent Production and Tolerance, Prolonged Metabolism, and Changes in the Cell's Transcriptional Program." Applied and Environmental Microbiology 69, no. 8 (2003): 4951–65. http://dx.doi.org/10.1128/aem.69.8.4951-4965.2003.

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ABSTRACT DNA array and Western analyses were used to examine the effects of groESL overexpression and host-plasmid interactions on solvent production in Clostridium acetobutylicum ATCC 824. Strain 824(pGROE1) was created to overexpress the groESL operon genes from a clostridial thiolase promoter. The growth of 824(pGROE1) was inhibited up to 85% less by a butanol challenge than that of the control strain, 824(pSOS95del). Overexpression of groESL resulted in increased final solvent titers 40% and 33% higher than those of the wild type and plasmid control strains, respectively. Active metabolism lasted two and one half times longer in 824(pGROE1) than in the wild type. Transcriptional analysis of 824(pGROE1) revealed increased expression of motility and chemotaxis genes and a decrease in the expression of the other major stress response genes. Decreased expression of the dnaKJ operon upon overexpression of groESL suggests that groESL functions as a modulator of the CIRCE regulon, which is shown here to include the hsp90 gene. Analysis of the plasmid control strain 824(pSOS95del) revealed complex host-plasmid interactions relative to the wild-type strain, resulting in prolonged biphasic growth and metabolism. Decreased expression of four DNA gyrases resulted in differential expression of many key primary metabolism genes. The ftsA and ftsZ genes were expressed at higher levels in 824(pSOS95del), revealing an altered cell division and sporulation pattern. Both transcriptional and Western analyses revealed elevated stress protein expression in the plasmid-carrying strain.

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Lin, Jiusheng, and Mark A. Wilson. "Escherichia coli Thioredoxin-like Protein YbbN Contains an Atypical Tetratricopeptide Repeat Motif and Is a Negative Regulator of GroEL." Journal of Biological Chemistry 286, no. 22 (2011): 19459–69. http://dx.doi.org/10.1074/jbc.m111.238741.

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Many proteins contain a thioredoxin (Trx)-like domain fused with one or more partner domains that diversify protein function by the modular construction of new molecules. The Escherichia coli protein YbbN is a Trx-like protein that contains a C-terminal domain with low homology to tetratricopeptide repeat motifs. YbbN has been proposed to act as a chaperone or co-chaperone that aids in heat stress response and DNA synthesis. We report the crystal structure of YbbN, which is an elongated molecule with a mobile Trx domain and four atypical tetratricopeptide repeat motifs. The Trx domain lacks a canonical CXXC active site architecture and is not a functional oxidoreductase. A variety of proteins in E. coli interact with YbbN, including multiple ribosomal protein subunits and a strong interaction with GroEL. YbbN acts as a mild inhibitor of GroESL chaperonin function and ATPase activity, suggesting that it is a negative regulator of the GroESL system. Combined with previous observations that YbbN enhances the DnaK-DnaJ-GrpE chaperone system, we propose that YbbN coordinately regulates the activities of these two prokaryotic chaperones, thereby helping to direct client protein traffic initially to DnaK. Therefore, YbbN may play a role in integrating the activities of different chaperone pathways in E. coli and related bacteria.

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Prakash, Jogadhenu S. S., Pilla Sankara Krishna, Kodru Sirisha, et al. "An RNA helicase, CrhR, regulates the low-temperature-inducible expression of heat-shock genes groES, groEL1 and groEL2 in Synechocystis sp. PCC 6803." Microbiology 156, no. 2 (2010): 442–51. http://dx.doi.org/10.1099/mic.0.031823-0.

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The crhR gene for RNA helicase, CrhR, was one of the most highly induced genes when the cyanobacterium Synechocystis sp. PCC 6803 was exposed to a downward shift in ambient temperature. Although CrhR may be involved in the acclimatization of cyanobacterial cells to low-temperature environments, its functional role during the acclimatization is not known. In the present study, we mutated the crhR gene by replacement with a spectinomycin-resistance gene cassette. The resultant ΔcrhR mutant exhibited a phenotype of slow growth at low temperatures. DNA microarray analysis of the genome-wide expression of genes, and Northern and Western blotting analyses indicated that mutation of the crhR gene repressed the low-temperature-inducible expression of heat-shock genes groEL1 and groEL2, at the transcript and protein levels. The kinetics of the groESL co-transcript and the groEL2 transcript after addition of rifampicin suggested that CrhR stabilized these transcripts at an early phase, namely 5–60 min, during acclimatization to low temperatures, and enhanced the transcription of these genes at a later time, namely 3–5 h. Our results suggest that CrhR regulates the low-temperature-inducible expression of these heat-shock proteins, which, in turn, may be essential for acclimatization of Synechocystis cells to low temperatures.

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Susin, Michelle F., Regina L. Baldini, Frederico Gueiros-Filho, and Suely L. Gomes. "GroES/GroEL and DnaK/DnaJ Have Distinct Roles in Stress Responses and during Cell Cycle Progression in Caulobacter crescentus." Journal of Bacteriology 188, no. 23 (2006): 8044–53. http://dx.doi.org/10.1128/jb.00824-06.

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ABSTRACT Misfolding and aggregation of protein molecules are major threats to all living organisms. Therefore, cells have evolved quality control systems for proteins consisting of molecular chaperones and proteases, which prevent protein aggregation by either refolding or degrading misfolded proteins. DnaK/DnaJ and GroES/GroEL are the best-characterized molecular chaperone systems in bacteria. In Caulobacter crescentus these chaperone machines are the products of essential genes, which are both induced by heat shock and cell cycle regulated. In this work, we characterized the viabilities of conditional dnaKJ and groESL mutants under different types of environmental stress, as well as under normal physiological conditions. We observed that C. crescentus cells with GroES/EL depleted are quite resistant to heat shock, ethanol, and freezing but are sensitive to oxidative, saline, and osmotic stresses. In contrast, cells with DnaK/J depleted are not affected by the presence of high concentrations of hydrogen peroxide, NaCl, and sucrose but have a lower survival rate after heat shock, exposure to ethanol, and freezing and are unable to acquire thermotolerance. Cells lacking these chaperones also have morphological defects under normal growth conditions. The absence of GroE proteins results in long, pinched filamentous cells with several Z-rings, whereas cells lacking DnaK/J are only somewhat more elongated than normal predivisional cells, and most of them do not have Z-rings. These findings indicate that there is cell division arrest, which occurs at different stages depending on the chaperone machine affected. Thus, the two chaperone systems have distinct roles in stress responses and during cell cycle progression in C. crescentus.

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Li, Jian, Yan Wang, Cui-ying Zhang, et al. "Myxococcus xanthus Viability Depends on GroEL Supplied by Either of Two Genes, but the Paralogs Have Different Functions during Heat Shock, Predation, and Development." Journal of Bacteriology 192, no. 7 (2010): 1875–81. http://dx.doi.org/10.1128/jb.01458-09.

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ABSTRACT Myxococcus xanthus DK1622 contains two paralogous groEL gene loci that possess both different sequences and different organizations within the genome. Deletion of either one of these two genes alone does not affect cell viability. However, deletion of both groEL genes results in cell death unless a complemented groEL1 or groEL2 gene is present. The groEL1 gene was determined to be essential for cell survival under heat shock conditions; a strain with mutant groEL2 caused cells to be more sensitive than the wild-type strain to higher temperatures. Mutants with a single deletion of either groEL1 (MXAN_4895) or groEL2 (MXAN_4467) had a growth curve similar to that of the wild-type strain DK1622 in medium containing hydrolyzed proteins as the substrate. However, when cells were cultured on medium containing either Escherichia coli cells or casein as the substrate, deletion of groEL2, but not groEL1, led to a deficiency in cell predation and macromolecular feeding. Furthermore, groEL1 was found to play an indispensable role in the development and sporulation of cells, but deletion of groEL2 had no visible effects. Our results suggest that, although alternatively required for cell viability, the products of the two groEL genes have divergent functions in the multicellular social life cycle of M. xanthus DK1622.

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Bjöersdorff, Anneli, Bodil Bagert, Robert F. Massung, Asiya Gusa, and Ingvar Eliasson. "Isolation and Characterization of Two European Strains of Ehrlichia phagocytophila of Equine Origin." Clinical and Vaccine Immunology 9, no. 2 (2002): 341–43. http://dx.doi.org/10.1128/cdli.9.2.341-343.2002.

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ABSTRACT We report the isolation and partial genetic characterization of two equine strains of granulocytic Ehrlichia of the genogroup Ehrlichia phagocytophila. Frozen whole-blood samples from two Swedish horses with laboratory-verified granulocytic ehrlichiosis were inoculated into HL-60 cell cultures. Granulocytic Ehrlichia was isolated and propagated from both horses. DNA extracts from the respective strains were amplified by PCR using primers directed towards the 16S rRNA gene, the groESL heat shock operon gene, and the ank gene. The amplified gene fragments were sequenced and compared to known sequences in the GenBank database. With respect to the 16S rRNA gene, the groESL gene, and the ank gene, the DNA sequences of the two equine Ehrlichia isolates were identical to sequences found in isolates from clinical cases of granulocytic ehrlichiosis in humans and domestic animals in Sweden. However, compared to amplified DNA from an American Ehrlichia strain of the E. phagocytophila genogroup, differences were found in the groESL gene and ank gene sequences.

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Musatovova, Oxana, Subramanian Dhandayuthapani, and Joel B. Baseman. "Transcriptional Heat Shock Response in the Smallest Known Self-Replicating Cell, Mycoplasma genitalium." Journal of Bacteriology 188, no. 8 (2006): 2845–55. http://dx.doi.org/10.1128/jb.188.8.2845-2855.2006.

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ABSTRACT Mycoplasma genitalium is a human bacterial pathogen linked to urethritis and other sexually transmitted diseases as well as respiratory and joint pathologies. Though its complete genome sequence is available, little is understood about the regulation of gene expression in this smallest known, self-replicating cell, as its genome lacks orthologues for most of the conventional bacterial regulators. Still, the transcriptional repressor HrcA (heat regulation at CIRCE [controlling inverted repeat of chaperone expression]) is predicted in the M. genitalium genome as well as three copies of its corresponding regulatory sequence CIRCE. We investigated the transcriptional response of M. genitalium to elevated temperatures and detected the differential induction of four hsp genes. Three of the up-regulated genes, which encode DnaK, ClpB, and Lon, possess CIRCE within their promoter regions, suggesting that the HrcA-CIRCE regulatory mechanism is functional. Additionally, one of three DnaJ-encoding genes was up-regulated, even though no known regulatory sequences were found in the promoter region. Transcript levels returned to control values after 1 h of incubation at 37°C, reinforcing the transient nature of the heat shock transcriptional response. Interestingly, neither of the groESL operon genes, which encode the GroEL chaperone and its cochaperone GroES, responded to heat shock. These data suggest that M. genitalium selectively regulates a limited number of genes in response to heat shock.

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Wang, Yan, Xi Li, Wenyan Zhang, Xiuwen Zhou, and Yue-zhong Li. "The groEL2 gene, but not groEL1, is required for biosynthesis of the secondary metabolite myxovirescin in Myxococcus xanthus DK1622." Microbiology 160, no. 3 (2014): 488–95. http://dx.doi.org/10.1099/mic.0.065862-0.

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Myxococcus xanthus DK1622 possesses two copies of the groEL gene: groEL1, which participates in development, and groEL2, which is involved in the predatory ability of cells. In this study, we determined that the groEL2 gene is required for the biosynthesis of the secondary metabolite myxovirescin (TA), which plays essential roles in predation. The groEL2-knockout mutant strain was defective in producing a zone of inhibition and displayed decreased killing ability against Escherichia coli, while the groEL1-knockout mutant strain exhibited little difference from the wild-type strain DK1622. HPLC revealed that deletion of the groEL2 gene blocked the production of TA, which was present in the groEL1-knockout mutant. The addition of exogenous TA rescued the inhibition and killing abilities of the groEL2-knockout mutant against E. coli. Analysis of GroEL domain-swapping mutants indicated that the C-terminal equatorial domain of GroEL2 was essential for TA production, while the N-terminal equatorial or apical domains of GroEL2 were not sufficient to rescue TA production of the groEL2 knockout.

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Kim, Dong-Gyun, Yu-Ri Kim, Eun-Young Kim, Hyun Min Cho, Sun-Hee Ahn, and In-Soo Kong. "Isolation of the groESL cluster from Vibrio anguillarum and PCR detection targeting groEL gene." Fisheries Science 76, no. 5 (2010): 803–10. http://dx.doi.org/10.1007/s12562-010-0266-y.

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Narberhaus, Franz, Michael Kowarik, Christoph Beck, and Hauke Hennecke. "Promoter Selectivity of the Bradyrhizobium japonicum RpoH Transcription Factors In Vivo and In Vitro." Journal of Bacteriology 180, no. 9 (1998): 2395–401. http://dx.doi.org/10.1128/jb.180.9.2395-2401.1998.

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ABSTRACT Expression of the dnaKJ andgroESL 1 heat shock operons ofBradyrhizobium japonicum depends on a ς32-like transcription factor. Three such factors (RpoH1, RpoH2, and RpoH3) have previously been identified in this organism. We report here that they direct transcription from some but not all ς32-type promoters when the respective rpoH genes are expressed inEscherichia coli. All three RpoH factors were purified as soluble C-terminally histidine-tagged proteins, although the bulk of overproduced RpoH3 was insoluble. The purified proteins were recognized by an anti-E. coli ς32 serum. While RpoH1 and RpoH2 productively interacted with E. coli core RNA polymerase and produced E. coli groE transcript in vitro, RpoH3 was unable to do so.B. japonicum core RNA polymerase was prepared and reconstituted with the RpoH proteins. Again, RpoH1 and RpoH2 were active, and they initiated transcription at theB. japonicum groESL 1 and dnaKJpromoters. In all cases, the in vitro start site was shown to be identical to the start site determined in vivo. Promoter competition experiments revealed that the B. japonicum dnaKJ andgroESL 1 promoters were suboptimal for transcription by RpoH1- or RpoH2-containing RNA polymerase from B. japonicum. In a mixture of different templates, the E. coli groESL promoter was preferred over any other promoter. Differences were observed in the specificities of both sigma factors toward B. japonicum rpoH-dependent promoters. We conclude that the primary function of RpoH2is to supply the cell with DnaKJ under normal growth conditions whereas RpoH1 is responsible mainly for increasing the level of GroESL1 after a heat shock.

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Schmid, Amy K., and Mary E. Lidstrom. "Involvement of Two Putative Alternative Sigma Factors in Stress Response of the Radioresistant Bacterium Deinococcus radiodurans." Journal of Bacteriology 184, no. 22 (2002): 6182–89. http://dx.doi.org/10.1128/jb.184.22.6182-6189.2002.

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ABSTRACT Two genes bearing similarity to alternative sigma factors were identified in the Deinococcus radiodurans genome sequence and designated sig1 and sig2. These genes were cloned and inactivated, and both were found to be important for survival during heat and ethanol stress, although the sig1 mutants displayed a more severe phenotype than the sig2 mutants. Reporter gene fusions to the groESL and dnaKJ operons transformed into these mutant backgrounds indicated that sig1 is required for the heat shock induction of groESL and dnaKJ, whereas sig2 mutants show a more moderate defect in dnaKJ induction and are not impaired for groESL induction. Essentiality tests suggested that neither sig1 nor sig2 is essential under all conditions. Sequence comparisons demonstrated that the sig1 gene product is classed distinctly with extracytoplasmic function (ECF) sigma factors, whereas Sig2 appears to be a more divergent sigma factor ortholog. These results suggest that sig1 encodes the major ECF-derived heat shock sigma factor in D. radiodurans and that it plays a central role in the positive regulation of heat shock genes. sig2, in contrast, appears to play a more minor role in heat shock protection and may serve to modulate the expression of some heat protective genes.

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Broadbent, J. R., C. J. Oberg, and L. Wei. "Characterization of the Lactobacillus helveticus groESL operon." Research in Microbiology 149, no. 4 (1998): 247–53. http://dx.doi.org/10.1016/s0923-2508(98)80300-8.

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Lee, W. T., K. C. Terlesky, and F. R. Tabita. "Cloning and characterization of two groESL operons of Rhodobacter sphaeroides: transcriptional regulation of the heat-induced groESL operon." Journal of bacteriology 179, no. 2 (1997): 487–95. http://dx.doi.org/10.1128/jb.179.2.487-495.1997.

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Lemos, José A. C., Yi-Ywan M. Chen, and Robert A. Burne. "Genetic and Physiologic Analysis of thegroE Operon and Role of the HrcA Repressor in Stress Gene Regulation and Acid Tolerance in Streptococcus mutans." Journal of Bacteriology 183, no. 20 (2001): 6074–84. http://dx.doi.org/10.1128/jb.183.20.6074-6084.2001.

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ABSTRACT Our working hypothesis is that the major molecular chaperones DnaK and GroE play central roles in the ability of oral bacteria to cope with the rapid and frequent stresses encountered in oral biofilms, such as acidification and nutrient limitation. Previously, our laboratory partially characterized the dnaK operon ofStreptococcus mutans(hrcA-grpE-dnaK) and demonstrated that dnaK is up-regulated in response to acid shock and sustained acidification (G. C. Jayaraman, J. E. Penders, and R. A. Burne, Mol. Microbiol. 25:329–341, 1997). Here, we show that thegroESL genes of S. mutans constitute an operon that is expressed from a stress-inducible ςA-type promoter located immediately upstream of a CIRCE element. GroEL protein and mRNA levels were elevated in cells exposed to a variety of stresses, including acid shock. A nonpolar insertion into hrcA was created and used to demonstrate that HrcA negatively regulates the expression of thegroEL and dnaK operons. The SM11 mutant, which had constitutively high levels of GroESL and roughly 50% of the DnaK protein found in the wild-type strain, was more sensitive to acid killing and could not lower the pH as effectively as the parent. The acid-sensitive phenotype of SM11 was, at least in part, attributable to lower F1F0-ATPase activity. A minimum of 10 proteins, in addition to GroES-EL, were found to be up-regulated in SM11. The data clearly indicate that HrcA plays a key role in the regulation of chaperone expression in S. mutans and that changes in the levels of the chaperones profoundly influence acid tolerance.

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Roncarati, Davide, Alberto Danielli, Gunther Spohn, Isabel Delany, and Vincenzo Scarlato. "Transcriptional Regulation of Stress Response and Motility Functions in Helicobacter pylori Is Mediated by HspR and HrcA." Journal of Bacteriology 189, no. 20 (2007): 7234–43. http://dx.doi.org/10.1128/jb.00626-07.

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ABSTRACT The hrcA and hspR genes of Helicobacter pylori encode two transcriptional repressor proteins that negatively regulate expression of the groES-groEL and hrcA-grpE-dnaK operons. While HspR was previously shown to bind far upstream of the promoters transcribing these operons, the binding sites of HrcA were not identified. Here, we demonstrate by footprinting analysis that HrcA binds to operator elements similar to the so-called CIRCE sequences overlapping both promoters. Binding of HspR and HrcA to their respective operators occurs in an independent manner, but the DNA binding activity of HrcA is increased in the presence of GroESL, suggesting that the GroE chaperonin system corepresses transcription together with HrcA. Comparative transcriptome analysis of the wild-type strain and hspR and hrcA singly and doubly deficient strains revealed that a set of 14 genes is negatively regulated by the action of one or both regulators, while a set of 29 genes is positively regulated. While both positive and negative regulation of transcription by HspR and/or HrcA could be confirmed by RNA primer extension analyses for two representative genes, binding of either regulator to the promoters could not be detected, indicating that transcriptional regulation at these promoters involves indirect mechanisms. Strikingly, 14 of the 29 genes which were found to be positively regulated by HspR or HrcA code for proteins involved in flagellar biosynthesis. Accordingly, loss of motility functions was observed for HspR and HrcA single or double mutants. The possible regulatory intersections of the heat shock response and flagellar assembly are discussed.

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Taguchi, Hideki, Keigo Tsukuda, Fumihiro Motojima, Ayumi Koike-Takeshita, and Masasuke Yoshida. "BeFxStops the Chaperonin Cycle of GroEL-GroES and Generates a Complex with Double Folding Chambers." Journal of Biological Chemistry 279, no. 44 (2004): 45737–43. http://dx.doi.org/10.1074/jbc.m406795200.

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Coupling with ATP hydrolysis and cooperating with GroES, the double ring chaperonin GroEL assists the folding of other proteins. Here we report novel GroEL-GroES complexes formed in fluoroberyllate (BeFx) that can mimic the phosphate part of the enzyme-bound nucleotides. In ATP, BeFxstops the functional turnover of GroEL by preventing GroES release and produces a symmetric 1:2 GroEL-GroES complex in which both GroEL rings contain ADP·BeFxand an encapsulated substrate protein. In ADP, the substrate protein-loaded GroEL cannot bind GroES. In ADPplusBeFx, however, it can bind GroES to form a stable 1:1 GroEL-GroES complex in which one of GroEL rings contains ADP·BeFxand an encapsulated substrate protein. This 1:1 GroEL-GroES complex is converted into the symmetric 1:2 GroEL-GroES complex when GroES is supplied in ATPplusBeFx. Thus, BeFxstabilizes two GroEL-GroES complexes; one with a single folding chamber and the other with double folding chambers. These results shed light on the intermediate ADP·Pinucleotide states in the functional cycle of GroEL.

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Tauschek, Marija, Christopher W. Hamilton, Leslie A. Hall, Chariya Chomvarin, Janet A. M. Fyfe, and John K. Davies. "Transcriptional analysis of the groESL operon of Neisseriagonorrhoeae." Gene 189, no. 1 (1997): 107–12. http://dx.doi.org/10.1016/s0378-1119(96)00842-6.

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de Leon, P., S. Marco, C. Isiegas, A. Marina, J. L. Carrascosa, and R. P. Mellado. "Streptomyces lividans groES, groEL1 and groEL2 genes." Microbiology 143, no. 11 (1997): 3563–71. http://dx.doi.org/10.1099/00221287-143-11-3563.

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MALMSTEN, J., D. GAVIER WIDÉN, G. RYDEVIK, et al. "Temporal and spatial variation in Anaplasma phagocytophilum infection in Swedish moose (Alces alces)." Epidemiology and Infection 142, no. 6 (2013): 1205–13. http://dx.doi.org/10.1017/s0950268813002094.

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SUMMARYThe occurrence of Anaplasma phagocytophilum was investigated in spleen and serum samples from Swedish moose (Alces alces) in southern Sweden (island and mainland). Samples were analysed for presence of A. phagocytophilum DNA by real-time PCR (n = 263), and for Anaplasma antibodies with ELISA serology (n = 234). All serum samples had antibodies against A. phagocytophilum. The mean DNA-based prevalence was 26·3%, and significant (P < 0·01) temporal, and spatial variation was found. Island moose had significantly (P < 0·001) higher prevalence of A. phagocytophilum DNA than moose from the mainland areas. Two samples were sequenced to determine genetic variation in the 16S rRNA and groESL genes. Genetic sequence similarity with the human granulocytic anaplasmosis agent, equine granulocytic ehrlichiosis agent, and different wildlife-associated A. phagocytophilum variants were observed in the 16S rRNA and groESL genes. Our study shows that moose are exposed to A. phagocytophilum in Sweden, and represent a potential wildlife reservoir of the pathogen.

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Akiko, Okamoto-Kainuma, Yan Wang, Kadono Sachiko, Tayama Kenji, Koizumi Yukimichi, and Yanagida Fujiharu. "Cloning and Characterization of groESL Operon in Acetobacter aceti." Journal of Bioscience and Bioengineering 94, no. 2 (2002): 140–47. http://dx.doi.org/10.1016/s1389-1723(02)80134-7.

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Hotokezaka, H., N. Ohara, H. Hayashida, et al. "Transcriptional analysis of the groESL operon from Porphyromonas gingivalis." Oral Microbiology and Immunology 12, no. 4 (1997): 236–39. http://dx.doi.org/10.1111/j.1399-302x.1997.tb00385.x.

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OKAMOTO-KAINUMA, AKIKO, YAN WANG, SACHIKO KADONO, KENJI TAYAMA, YUKIMICHI KOIZUMI, and FUJIHARU YANAGIDA. "Cloning and Characterization of groESL Operon in Acetobacter aceti." Journal of Bioscience and Bioengineering 94, no. 2 (2002): 140–47. http://dx.doi.org/10.1263/jbb.94.140.

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Hung, Wei-Chung, Jui-Chang Tsai, Po-Ren Hsueh, Jean-San Chia, and Lee-Jene Teng. "Species identification of mutans streptococci by groESL gene sequence." Journal of Medical Microbiology 54, no. 9 (2005): 857–62. http://dx.doi.org/10.1099/jmm.0.46180-0.

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Ventura, Marco, Carlos Canchaya, Ralf Zink, Gerald F. Fitzgerald, and Douwe van Sinderen. "Characterization of the groEL and groES Loci in Bifidobacterium breve UCC 2003: Genetic, Transcriptional, and Phylogenetic Analyses." Applied and Environmental Microbiology 70, no. 10 (2004): 6197–209. http://dx.doi.org/10.1128/aem.70.10.6197-6209.2004.

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ABSTRACT The bacterial heat shock response is characterized by the elevated expression of a number of chaperone complexes, including the GroEL and GroES proteins. The groES and groEL genes are highly conserved among eubacteria and are typically arranged as an operon. Genome analysis of Bifidobacterium breve UCC 2003 revealed that the groES and groEL genes are located in different chromosomal regions. The heat inducibility of the groEL and groES genes of B. breve UCC 2003 was verified by slot blot analysis. Northern blot analyses showed that the cspA gene is cotranscribed with the groEL gene, while the groES gene is transcribed as a monocistronic unit. The transcription initiation sites of these two mRNAs were determined by primer extension. Sequence and transcriptional analyses of the region flanking the groEL and groES genes of various bifidobacteria revealed similar groEL-cspA and groES gene units, suggesting a novel genetic organization of these chaperones. Phylogenetic analysis of the available bifidobacterial groES and groEL genes suggested that these genes evolved differently. Discrepancies in the phylogenetic positioning of groES-based trees make this gene an unreliable molecular marker. On the other hand, the bifidobacterial groEL gene sequences can be used as an alternative to current methods for tracing Bifidobacterium species, particularly because they allow a high level of discrimination between closely related species of this genus.

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Noshiro, Daisuke, and Toshio Ando. "Substrate protein dependence of GroEL–GroES interaction cycle revealed by high-speed atomic force microscopy imaging." Philosophical Transactions of the Royal Society B: Biological Sciences 373, no. 1749 (2018): 20170180. http://dx.doi.org/10.1098/rstb.2017.0180.

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A double-ring-shaped tetradecameric GroEL complex assists proper protein folding in cooperation with the cochaperonin GroES. The dynamic GroEL–GroES interaction reflects the allosteric intra- and inter-ring communications and the chaperonin reaction. Therefore, revealing this dynamic interaction is essential to understanding the allosteric communications and the operation mechanism of GroEL. Nevertheless, how this interaction proceeds in the chaperonin cycle has long been controversial. Here, we directly image the dynamic GroEL–GroES interaction under conditions with and without foldable substrate protein using high-speed atomic force microscopy. Then, the imaging results obtained under these conditions and our previous results in the presence of unfoldable substrate are compared. The molecular movies reveal that the entire reaction pathway is highly complicated but basically identical irrespective of the substrate condition. A prominent (but moderate) difference is in the population distribution of intermediate species: symmetric GroEL : GroES 2 and asymmetric GroEL : GroES 1 complexes, and GroES–unbound GroEL. This difference is mainly attributed to the longer lifetime of GroEL : GroES 1 complexes in the presence of foldable substrate. Moreover, the inter-ring communication, which is the basis for the alternating action of the two rings, occurs at two distinct (GroES association and dissociation) steps in the main reaction pathway, irrespective of the substrate condition. This article is part of a discussion meeting issue ‘Allostery and molecular machines’.

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Hotokezaka, Hitoshi, Hideaki Hayashida, Naoya Ohara, Hiroko Nomaguchi, Kazuhide Kobayashi, and Takeshi Yamada. "Cloning and sequencing of the groESL homologue from Porphyromonas gingivalis." Biochimica et Biophysica Acta (BBA) - Gene Structure and Expression 1219, no. 1 (1994): 175–78. http://dx.doi.org/10.1016/0167-4781(94)90265-8.

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Radulovic, Suzana, M. Sayeedur Rahman, Magda S. Beier, and Abdu F. Azad. "Molecular and functional analysis of the Rickettsia typhi groESL operon." Gene 298, no. 1 (2002): 41–48. http://dx.doi.org/10.1016/s0378-1119(02)00922-8.

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Li, M., and S. L. Wong. "Cloning and characterization of the groESL operon from Bacillus subtilis." Journal of Bacteriology 174, no. 12 (1992): 3981–92. http://dx.doi.org/10.1128/jb.174.12.3981-3992.1992.

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Sameshima, Tomoya, Ryo Iizuka, Taro Ueno, and Takashi Funatsu. "Denatured proteins facilitate the formation of the football-shaped GroEL–(GroES)2 complex." Biochemical Journal 427, no. 2 (2010): 247–54. http://dx.doi.org/10.1042/bj20091845.

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Controversy exists over whether the chaperonin GroEL forms a GroEL–(GroES)2 complex (football-shaped complex) during its reaction cycle. We have revealed previously the existence of the football-shaped complex in the chaperonin reaction cycle using a FRET (fluorescence resonance energy transfer) assay [Sameshima, Ueno, Iizuka, Ishii, Terada, Okabe and Funatsu (2008) J. Biol. Chem. 283, 23765–23773]. Although denatured proteins alter the ATPase activity of GroEL and the dynamics of the GroEL–GroES interaction, the effect of denatured proteins on the formation of the football-shaped complex has not been characterized. In the present study, a FRET assay was used to demonstrate that denatured proteins facilitate the formation of the football-shaped complex. The presence of denatured proteins was also found to increase the rate of association of GroES to the trans-ring of GroEL. Furthermore, denatured proteins decrease the inhibitory influence of ADP on ATP-induced association of GroES to the trans-ring of GroEL. From these findings we conclude that denatured proteins facilitate the dissociation of ADP from the trans-ring of GroEL and the concomitant association of ATP and the second GroES.

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Tran, Huyen-Thi, Jongha Lee, Hyunjae Park, et al. "Crystal Structure of Chaperonin GroEL from Xanthomonas oryzae pv. oryzae." Crystals 9, no. 8 (2019): 399. http://dx.doi.org/10.3390/cryst9080399.

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Xanthomonas oryzae pv. oryzae (Xoo) is a plant pathogen that causes bacterial blight of rice, with outbreaks occurring in most rice-growing countries. Thus far, there is no effective pesticide against bacterial blight. Chaperones in bacterial pathogens are important for the stabilization and delivery of effectors into host cells to cause disease. In bacteria, GroEL/GroES complex mediates protein folding and protects proteins against misfolding and aggregation caused by environmental stress. We determined the crystal structure of GroEL from Xanthomonas oryzae pv. oryzae (XoGroEL) at 3.2 Å resolution, which showed the open form of two conserved homoheptameric rings stacked back-to-back. In the open form structure, the apical domain of XoGroEL had a higher B factor than the intermediate and equatorial domains, indicating that the apical domain had a flexible conformation before the binding of substrate unfolded protein and ATP. The XoGroEL structure will be helpful in understanding the function and catalytic mechanism of bacterial chaperonin GroELs.

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