Journal articles: 'Photocyclo addition'

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Hart, Jaynee E., Stuart Sullivan, Paweł Hermanowicz, Jan Petersen, L. Aranzazú Diaz-Ramos, David J. Hoey, Justyna Łabuz, and John M. Christie. "Engineering the phototropin photocycle improves photoreceptor performance and plant biomass production." Proceedings of the National Academy of Sciences 116, no. 25 (June 3, 2019): 12550–57. http://dx.doi.org/10.1073/pnas.1902915116.

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The ability to enhance photosynthetic capacity remains a recognized bottleneck to improving plant productivity. Phototropin blue light receptors (phot1 and phot2) optimize photosynthetic efficiency in Arabidopsis thaliana by coordinating multiple light-capturing processes. In this study, we explore the potential of using protein engineering to improve photoreceptor performance and thereby plant growth. We demonstrate that targeted mutagenesis can decrease or increase the photocycle lifetime of Arabidopsis phototropins in vitro and show that these variants can be used to reduce or extend the duration of photoreceptor activation in planta. Our findings show that slowing the phototropin photocycle enhanced several light-capturing responses, while accelerating it reduced phototropin’s sensitivity for chloroplast accumulation movement. Moreover, plants engineered to have a slow-photocycling variant of phot1 or phot2 displayed increased biomass production under low-light conditions as a consequence of their improved sensitivity. Together, these findings demonstrate the feasibility of engineering photoreceptors to manipulate plant growth and offer additional opportunities to enhance photosynthetic competence, particularly under suboptimal light regimes.

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Bose, Salil, Anup K. Mukhopadyay, Swetlana Dracheva, and Richard W. Hendler. "Role of Salt in Reconstituting Photocycle Behavior in Triton-Damaged Purple Membranes by Addition of Native Lipids." Journal of Physical Chemistry B 101, no. 49 (December 1997): 10584–87. http://dx.doi.org/10.1021/jp972260h.

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Shigemura, Shunta, Shoko Hososhima, Hideki Kandori, and Satoshi P. Tsunoda. "Ion Channel Properties of a Cation Channelrhodopsin, Gt_CCR4." Applied Sciences 9, no. 17 (August 21, 2019): 3440. http://dx.doi.org/10.3390/app9173440.

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We previously reported a cation channelrhodopsin, Gt_CCR4, which is one of the 44 types of microbial rhodopsins from a cryptophyte flagellate, Guillardia theta. Due to the modest homology of amino acid sequences with a chlorophyte channelrhodopsin such as Cr_ChR2 from Chlamydomonas reinhardtii, it has been proposed that a family of cryptophyte channelrhodopsin, including Gt_CCR4, has a distinct molecular mechanism for channel gating and ion permeation. In this study, we compared the photocurrent properties, cation selectivity and kinetics between well-known Cr_ChR2 and Gt_CCR4 by a conventional path clamp method. Large and stable light-induced cation conduction by Gt_CCR4 at the maximum absorbing wavelength (530 nm) was observed with only small inactivation (15%), whereas the photocurrent of Cr_ChR2 exhibited significant inactivation (50%) and desensitization. The light sensitivity of Gt_CCR4 was higher (EC50 = 0.13 mW/mm2) than that of Cr_ChR2 (EC50 = 0.80 mW/mm2) while the channel open life time (photocycle speed) was in the same range as that of Cr_ChR2 (25~30 ms for Gt_CCR4 and 10~15 ms for Cr_ChR2). This observation implies that Gt_CCR4 enables optical neuronal spiking with weak light in high temporal resolution when applied in neuroscience. Furthermore, we demonstrated high Na+ selectivity of Gt_CCR4 in which the selectivity ratio for Na+ was 37-fold larger than that for Cr_ChR2, which primarily conducts H+. On the other hand, Gt_CCR4 conducted almost no H+ and no Ca2+ under physiological conditions. These results suggest that ion selectivity in Gt_CCR4 is distinct from that in Cr_ChR2. In addition, a unique red-absorbing and stable intermediate in the photocycle was observed, indicating a photochromic property of Gt_CCR4.

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Schmidt, Marius, Tim Graber, Robert Henning, and Vukica Srajer. "Five-dimensional crystallography." Acta Crystallographica Section A Foundations of Crystallography 66, no. 2 (February 18, 2010): 198–206. http://dx.doi.org/10.1107/s0108767309054166.

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A method for determining a comprehensive chemical kinetic mechanism in macromolecular reactions is presented. The method is based on five-dimensional crystallography, where, in addition to space and time, temperature is also taken into consideration and an analysis based on singular value decomposition is applied. First results of such a time-resolved crystallographic study are presented. Temperature-dependent time-resolved X-ray diffraction measurements were conducted on the newly upgraded BioCARS 14-ID-B beamline at the Advanced Photon Source and aimed at elucidating a comprehensive kinetic mechanism of the photoactive yellow protein photocycle. Extensive time series of crystallographic data were collected at two temperatures, 293 K and 303 K. Relaxation times of the reaction extracted from these time series exhibit measurable differences for the two temperatures, hence demonstrating that five-dimensional crystallography is feasible.

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Goings, Joshua J., Pengfei Li, Qiwen Zhu, and Sharon Hammes-Schiffer. "Formation of an unusual glutamine tautomer in a blue light using flavin photocycle characterizes the light-adapted state." Proceedings of the National Academy of Sciences 117, no. 43 (October 9, 2020): 26626–32. http://dx.doi.org/10.1073/pnas.2016719117.

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Blue light using flavin (BLUF) photoreceptor proteins are critical for many light-activated biological processes and are promising candidates for optogenetics because of their modular nature and long-range signaling capabilities. Although the photocycle of the Slr1694 BLUF domain has been characterized experimentally, the identity of the light-adapted state following photoexcitation of the bound flavin remains elusive. Herein hybrid quantum mechanical/molecular mechanical (QM/MM) molecular dynamics simulations of this photocycle provide a nonequilibrium dynamical picture of a possible mechanism for the formation of the light-adapted state. Photoexcitation of the flavin induces a forward proton-coupled electron transfer (PCET) process that leads to the formation of an imidic acid tautomer of Gln50. The calculations herein show that the subsequent rotation of Gln50 allows a reverse PCET process that retains this tautomeric form. In the resulting purported light-adapted state, the glutamine tautomer forms a hydrogen bond with the flavin carbonyl group. Additional ensemble-averaged QM/MM calculations of the dark-adapted and purported light-adapted states demonstrate that the light-adapted state with the imidic acid glutamine tautomer reproduces the experimentally observed spectroscopic signatures. Specifically, the calculations reproduce the red shifts in the flavin electronic absorption and carbonyl stretch infrared spectra in the light-adapted state. Further hydrogen-bonding analyses suggest the formation of hydrogen-bonding interactions between the flavin and Arg65 in the light-adapted state, providing a plausible explanation for the experimental observation of faster photoinduced PCET in this state. These characteristics of the light-adapted state may also be essential for the long-range signaling capabilities of this photoreceptor protein.

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Xu, Qian-Zhao, Pavlo Bielytskyi, James Otis, Christina Lang, Jon Hughes, Kai-Hong Zhao, Aba Losi, Wolfgang Gärtner, and Chen Song. "MAS NMR on a Red/Far-Red Photochromic Cyanobacteriochrome All2699 from Nostoc." International Journal of Molecular Sciences 20, no. 15 (July 26, 2019): 3656. http://dx.doi.org/10.3390/ijms20153656.

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Unlike canonical phytochromes, the GAF domain of cyanobacteriochromes (CBCRs) can bind bilins autonomously and is sufficient for functional photocycles. Despite the astonishing spectral diversity of CBCRs, the GAF1 domain of the three-GAF-domain photoreceptor all2699 from the cyanobacterium Nostoc 7120 is the only CBCR-GAF known that converts from a red-absorbing (Pr) dark state to a far-red-absorbing (Pfr) photoproduct, analogous to the more conservative phytochromes. Here we report a solid-state NMR spectroscopic study of all2699g1 in its Pr state. Conclusive NMR evidence unveils a particular stereochemical heterogeneity at the tetrahedral C31 atom, whereas the crystal structure shows exclusively the R-stereochemistry at this chiral center. Additional NMR experiments were performed on a construct comprising the GAF1 and GAF2 domains of all2699, showing a greater precision in the chromophore–protein interactions in the GAF1-2 construct. A 3D Pr structural model of the all2699g1-2 construct predicts a tongue-like region extending from the GAF2 domain (akin to canonical phytochromes) in the direction of the chromophore, shielding it from the solvent. In addition, this stabilizing element allows exclusively the R-stereochemistry for the chromophore-protein linkage. Site-directed mutagenesis performed on three conserved motifs in the hairpin-like tip confirms the interaction of the tongue region with the GAF1-bound chromophore.

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Griesbeck, Axel G., Manabu Abe, and Samir Bondock. "Selectivity Control in Electron Spin Inversion Processes: Regio- and Stereochemistry of Paternò−Büchi Photocyclo- additions as a Powerful Tool for Mapping Intersystem Crossing Processes." Accounts of Chemical Research 37, no. 12 (December 2004): 919–28. http://dx.doi.org/10.1021/ar040081u.

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Mueller, Maria. "Light-induced Helix Movements in Channelrhodopsin-2." Acta Crystallographica Section A Foundations and Advances 70, a1 (August 5, 2014): C1067. http://dx.doi.org/10.1107/s2053273314089323.

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Electron crystallography has the unique advantage of visualizing membrane proteins in a native-like lipid environment, which likely favors the native conformation. In addition, it allows for the protein to undergo conformational changes in response to their activating signals. We used 2D crystals of channelrhodopsin-2, a cation-selective light-gated channel from Chlamydomonas reinhardtii (Nagel et al., 2003) to study light-induced conformational changes of this intriguing channel, which is currently a powerful tool in optogenetics. Therefore, 2D crystals of the slow photocycling C128T ChR2 mutant were exposed to 473 nm light and rapidly frozen to trap the open state. Projection difference maps at 6 Å resolution show the location, extent and direction of light-induced conformational changes in ChR2 during the transition from the closed state to the ion-conducting open state. Difference peaks indicate that transmembrane helices (TMHs) 2, 6, and 7 reorient or rearrange during the photocycle. No major differences were found near TMH3 and 4 at the dimer interface. While conformational changes in TMH6 and 7 are known from other microbial-type rhodopsins, our results indicate that TMH2 has a key role in light-induced channel opening and closing in ChR2.

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Froehlich, Allan C., Bosl Noh, Richard D. Vierstra, Jennifer Loros, and Jay C. Dunlap. "Genetic and Molecular Analysis of Phytochromes from the Filamentous Fungus Neurospora crassa." Eukaryotic Cell 4, no. 12 (December 2005): 2140–52. http://dx.doi.org/10.1128/ec.4.12.2140-2152.2005.

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ABSTRACT Phytochromes (Phys) comprise a superfamily of red-/far-red-light-sensing proteins. Whereas higher-plant Phys that control numerous growth and developmental processes have been well described, the biochemical characteristics and functions of the microbial forms are largely unknown. Here, we describe analyses of the expression, regulation, and activities of two Phys in the filamentous fungus Neurospora crassa. In addition to containing the signature N-terminal domain predicted to covalently associate with a bilin chromophore, PHY-1 and PHY-2 contain C-terminal histidine kinase and response regulator motifs, implying that they function as hybrid two-component sensor kinases activated by light. A bacterially expressed N-terminal fragment of PHY-2 covalently bound either biliverdin or phycocyanobilin in vitro, with the resulting holoprotein displaying red-/far-red-light photochromic absorption spectra and a photocycle in vitro. cDNA analysis of phy-1 and phy-2 revealed two splice isoforms for each gene. The levels of the phy transcripts are not regulated by light, but the abundance of the phy-1 mRNAs is under the control of the circadian clock. Phosphorylated and unphosphorylated forms of PHY-1 were detected; both species were found exclusively in the cytoplasm, with their relative abundances unaffected by light. Strains containing deletions of phy-1 and phy-2, either singly or in tandem, were not compromised in any known photoresponses in Neurospora, leaving their function(s) unclear.

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Xu, Xiuling, Astrid Höppner, Christian Wiebeler, Kai-Hong Zhao, Igor Schapiro, and Wolfgang Gärtner. "Structural elements regulating the photochromicity in a cyanobacteriochrome." Proceedings of the National Academy of Sciences 117, no. 5 (January 21, 2020): 2432–40. http://dx.doi.org/10.1073/pnas.1910208117.

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The three-dimensional (3D) crystal structures of the GAF3 domain of cyanobacteriochrome Slr1393 (Synechocystis PCC6803) carrying a phycocyanobilin chromophore could be solved in both 15-Z dark-adapted state, Pr, λmax = 649 nm, and 15-E photoproduct, Pg, λmax = 536 nm (resolution, 1.6 and 1.86 Å, respectively). The structural data allowed identifying the large spectral shift of the Pr-to-Pg conversion as resulting from an out-of-plane rotation of the chromophore’s peripheral rings and an outward movement of a short helix formed from a formerly unstructured loop. In addition, a third structure (2.1-Å resolution) starting from the photoproduct crystals allowed identification of elements that regulate the absorption maxima. In this peculiar form, generated during X-ray exposition, protein and chromophore conformation still resemble the photoproduct state, except for the D-ring already in 15-Z configuration and tilted out of plane akin the dark state. Due to its formation from the photoproduct, it might be considered an early conformational change initiating the parental state-recovering photocycle. The high quality and the distinct features of the three forms allowed for applying quantum-chemical calculations in the framework of multiscale modeling to rationalize the absorption maxima changes. A systematic analysis of the PCB chromophore in the presence and absence of the protein environment showed that the direct electrostatic effect is negligible on the spectral tuning. However, the protein forces the outer pyrrole rings of the chromophore to deviate from coplanarity, which is identified as the dominating factor for the color regulation.

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Bannister, Saskia, Elena Böhm, Thomas Zinn, Thomas Hellweg, and Tilman Kottke. "Arguments for an additional long-lived intermediate in the photocycle of the full-length aureochrome 1c receptor: A time-resolved small-angle X-ray scattering study." Structural Dynamics 6, no. 3 (May 2019): 034701. http://dx.doi.org/10.1063/1.5095063.

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Gaidenko, Tatiana A., Tae-Jong Kim, Andrea L. Weigel, Margaret S. Brody, and Chester W. Price. "The Blue-Light Receptor YtvA Acts in the Environmental Stress Signaling Pathway of Bacillus subtilis." Journal of Bacteriology 188, no. 17 (September 1, 2006): 6387–95. http://dx.doi.org/10.1128/jb.00691-06.

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ABSTRACT The general stress response of the bacterium Bacillus subtilis is regulated by a partner-switching mechanism in which serine and threonine phosphorylation controls protein interactions in the stress-signaling pathway. The environmental branch of this pathway contains a family of five paralogous proteins that function as negative regulators. Here we present genetic evidence that a sixth paralog, YtvA, acts as a positive regulator in the same environmental signaling branch. We also present biochemical evidence that YtvA and at least three of the negative regulators can be isolated from cell extracts in a large environmental signaling complex. YtvA differs from these associated negative regulators by its flavin mononucleotide (FMN)-containing light-oxygen-voltage domain. Others have shown that this domain has the photochemistry expected for a blue-light sensor, with the covalent linkage of the FMN chromophore to cysteine 62 composing a critical part of the photocycle. Consistent with the view that light intensity modifies the output of the environmental signaling pathway, we found that cysteine 62 is required for YtvA to exert its positive regulatory role in the absence of other stress. Transcriptional analysis of the ytvA structural gene indicated that it provides the entry point for at least one additional environmental input, mediated by the Spx global regulator of disulfide stress. These results support a model in which the large signaling complex serves to integrate multiple environmental signals in order to modulate the general stress response.

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Zimányi, László, Áron Sipos, Ferenc Sarlós, Rita Nagypál, and Géza I. Groma. "Machine-learning model selection and parameter estimation from kinetic data of complex first-order reaction systems." PLOS ONE 16, no. 8 (August 9, 2021): e0255675. http://dx.doi.org/10.1371/journal.pone.0255675.

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Dealing with a system of first-order reactions is a recurrent issue in chemometrics, especially in the analysis of data obtained by spectroscopic methods applied on complex biological systems. We argue that global multiexponential fitting, the still common way to solve such problems, has serious weaknesses compared to contemporary methods of sparse modeling. Combining the advantages of group lasso and elastic net—the statistical methods proven to be very powerful in other areas—we created an optimization problem tunable from very sparse to very dense distribution over a large pre-defined grid of time constants, fitting both simulated and experimental multiwavelength spectroscopic data with high computational efficiency. We found that the optimal values of the tuning hyperparameters can be selected by a machine-learning algorithm based on a Bayesian optimization procedure, utilizing widely used or novel versions of cross-validation. The derived algorithm accurately recovered the true sparse kinetic parameters of an extremely complex simulated model of the bacteriorhodopsin photocycle, as well as the wide peak of hypothetical distributed kinetics in the presence of different noise levels. It also performed well in the analysis of the ultrafast experimental fluorescence kinetics data detected on the coenzyme FAD in a very wide logarithmic time window. We conclude that the primary application of the presented algorithms—implemented in available software—covers a wide area of studies on light-induced physical, chemical, and biological processes carried out with different spectroscopic methods. The demand for this kind of analysis is expected to soar due to the emerging ultrafast multidimensional infrared and electronic spectroscopic techniques that provide very large and complex datasets. In addition, simulations based on our methods could help in designing the technical parameters of future experiments for the verification of particular hypothetical models.

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Schuster, David I., George E. Heibel, and Jan Woning. "The Mechanism of Interaction of Triplet 3-Methylcyclohex-2-en-1-one with Maleo- and fumarodinitrile: Evidence for Direct Formation of Triplet 1,4-Biradicals in[2+ 2] Photocyclo- additions without the Intermediacy of Exciplexes." Angewandte Chemie International Edition in English 30, no. 10 (October 1991): 1345–47. http://dx.doi.org/10.1002/anie.199113451.

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Wang, Jianjun, Toshiki Aoki, Lijia Liu, Takeshi Namikoshi, Masahiro Teraguchi, and Takashi Kaneko. "Facile Synthesis of an Amphiphilic 1,3,5-Trisubstituted Benzene as a Novel Surface Modifier by Selective Photocyclic Aromatization and Efficient Improvement of Oxygen Permselectivity by the Addition of the Surface Modifier." Chemistry Letters 42, no. 9 (September 5, 2013): 1090–92. http://dx.doi.org/10.1246/cl.130372.

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O'Donoghue, Beth, Kerrie NicAogáin, Claire Bennett, Alan Conneely, Teresa Tiensuu, Jörgen Johansson, and Conor O'Byrne. "Blue-Light Inhibition of Listeria monocytogenes Growth Is Mediated by Reactive Oxygen Species and Is Influenced by σBand the Blue-Light Sensor Lmo0799." Applied and Environmental Microbiology 82, no. 13 (April 29, 2016): 4017–27. http://dx.doi.org/10.1128/aem.00685-16.

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ABSTRACTListeria monocytogenessenses blue light via the flavin mononucleotide-containing sensory protein Lmo0799, leading to activation of the general stress response sigma factor SigB (σB). In this study, we investigated the physiological response of this foodborne pathogen to blue light. We show that blue light (460 to 470 nm) doses of 1.5 to 2 mW cm−2cause inhibition of growth on agar-based and liquid culture media. The inhibitory effects are dependent on cell density, with reduced effects evident when high cell numbers are present. The addition of 20 mM dimethylthiourea, a scavenger of reactive oxygen species, or catalase to the medium reverses the inhibitory effects of blue light, suggesting that growth inhibition is mediated by the formation of reactive oxygen species. A mutant strain lacking σB(ΔsigB) was found to be less inhibited by blue light than the wild type, likely indicating the energetic cost of deploying the general stress response. When a lethal dose of light (8 mW cm−2) was applied to cells, the ΔsigBmutant displayed a marked increase in sensitivity to light compared to the wild type. To investigate the role of the blue-light sensor Lmo0799, mutants were constructed that either had a deletion of the gene (Δlmo0799) or alteration in a conserved cysteine residue at position 56, which is predicted to play a pivotal role in the photocycle of the protein (lmo0799C56A). Both mutants displayed phenotypes similar to the ΔsigBmutant in the presence of blue light, providing genetic evidence that residue 56 is critical for light sensing inL. monocytogenes. Taken together, these results demonstrate thatL. monocytogenesis inhibited by blue light in a manner that depends on reactive oxygen species, and they demonstrate clear light-dependent phenotypes associated with σBand the blue-light sensor Lmo0799.IMPORTANCEListeria monocytogenesis a bacterial foodborne pathogen that can cause life-threatening infections in humans. It is known to be able to sense and respond to visible light. In this study, we examine the effects of blue light on the growth and survival of this pathogen. We show that growth can be inhibited at comparatively low doses of blue light, and that at higher doses,L. monocytogenescells are killed. We present evidence suggesting that blue light inhibits this organism by causing the production of reactive oxygen species, such as hydrogen peroxide. We help clarify the mechanism of light sensing by constructing a “blind” version of the blue-light sensor protein. Finally, we show that activation of the general stress response by light has a negative effect on growth, probably because cellular resources are diverted into protective mechanisms rather than growth.

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Tominaga, Yoko, Kensaku Suzuki, Matsuo Uemura, and Yukio Kawamura. "In Planta Monitoring of Cold-Responsive Promoter Activity Reveals a Distinctive Photoperiodic Response in Cold Acclimation." Plant and Cell Physiology, November 3, 2020. http://dx.doi.org/10.1093/pcp/pcaa138.

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Abstract Plant cold acclimation involves complicated pathways that integrate signals from temperature changes and light conditions. To understand plant responses to environmental signals in detail, molecular events that are regulated by temperature and light must be investigated at the whole-plant level in a nondestructive way. Using the promoter of COR15A connected to the luciferase reporter gene as a cold-responsive indicator, we developed an in planta monitoring system for gene expression under controlled temperature and photoperiod conditions. COR15A promoter activity was intensified by day–night cycles at 2°C, while its induction was abruptly suppressed in the dark at 8°C or higher, indicating a difference in responsiveness to photocycle between these two acclimation conditions. Freeze–thawing tests of whole plants proved that lower acclimation temperature resulted in higher tolerance to freezing, consistent with the temperature-dependent induction of COR15A. Inhibition of photosynthetic electron transport by 3-(3,4-dichlorophenyl)-1,1-dimethylurea eliminated the responsiveness to the day–night cycles at 2°C, indicating a possibility that the photosynthetic redox and/or the accumulation of photosynthates modulate COR15A responsiveness to photoperiod during cold acclimation, in addition to the well-known regulation by CBF (C-repeat binding factor) genes. These findings indicate that the cold-responsive promoter is regulated by distinctive mechanisms dependent on temperature and simultaneously affected by photocycle and photosynthesis.

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Luo, Wei, Chao Xue, Yuzheng Zhao, Huili Zhang, Zhiming Rao, and Xiaobin Yu. "Blakeslea trispora Photoreceptors: Identification and Functional Analysis." Applied and Environmental Microbiology 86, no. 8 (February 7, 2020). http://dx.doi.org/10.1128/aem.02962-19.

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ABSTRACT Blakeslea trispora is an industrial fungal species used for large-scale production of carotenoids. However, B. trispora light-regulated physiological processes, such as carotenoid biosynthesis and phototropism, are not fully understood. In this study, we isolated and characterized three photoreceptor genes, btwc-1a, btwc-1b, and btwc-1c, in B. trispora. Bioinformatics analyses of these genes and their protein sequences revealed that the functional domains (PAS/LOV [Per-ARNT-Sim/light-oxygen-voltage] domain and zinc finger structure) of the proteins have significant homology to those of other fungal blue-light regulator proteins expressed by Mucor circinelloides and Neurospora crassa. The photoreceptor proteins were synthesized by heterologous expression in Escherichia coli. The chromogenic groups consisting of flavin adenine dinucleotide (FAD) and flavin mononucleotide (FMN) were detected to accompany BTWC-1 proteins by using high-performance liquid chromatography (HPLC) and fluorescence spectrometry, demonstrating that the proteins may be photosensitive. The absorbance changes of the purified BTWC-1 proteins seen under dark and light conditions indicated that they were light responsive and underwent a characteristic photocycle by light induction. Site-directed mutagenesis of the cysteine residual (Cys) in BTWC-1 did not affect the normal expression of the protein in E. coli but did lead to the loss of photocycle response, indicating that Cys represents a flavin-binding domain for photon detection. We then analyzed the functions of BTWC-1 proteins by complementing btwc-1a, btwc-1b, and btwc-1c into the counterpart knockout strains of M. circinelloides for each mcwc-1 gene. Transformation of the btwc-1a complement into mcwc-1a knockout strains restored the positive phototropism, while the addition of btwc-1c complement remedied the deficiency of carotene biosynthesis in the mcwc-1c knockout strains under conditions of illumination. These results indicate that btwc-1a and btwc-1c are involved in phototropism and light-inducible carotenogenesis. Thus, btwc-1 genes share a conserved flavin-binding domain and act as photoreceptors for control of different light transduction pathways in B. trispora. IMPORTANCE Studies have confirmed that light-regulated carotenogenesis is prevalent in filamentous fungi, especially in mucorales. However, few investigations have been done to understand photoinduced synthesis of carotenoids and related mechanisms in B. trispora, a well-known industrial microbial strains. In the present study, three photoreceptor genes in B. trispora were cloned, expressed, and characterized by bioinformatics and photoreception analyses, and then in vivo functional analyses of these genes were constructed in M. circinelloides. The results of this study will lead to a better understanding of photoreception and light-regulated carotenoid synthesis and other physiological responses in B. trispora.

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Journal articles on the topic 'Photocyclo addition'

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