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Journal articles on the topic 'Amino β-lactam'

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Published: 5 June 2025
Last updated: 1 August 2025

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1

Kanwar, Seema, та Sain D. Sharma. "(Chloromethylene)Dimethylammonium Chloride: A Highly Efficient Reagent for the Synthesis of β-Lactams from β-Amino Acids". Journal of Chemical Research 2005, № 11 (2005): 705–7. http://dx.doi.org/10.3184/030823405774909414.

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(Chloromethylene)dimethylammonium chloride 1, is a unique reagent that conveniently and efficiently mediates the amide bond formation in β-lactams via cyclodehydration of β-amino acids leading to β-lactam formation. The process involves the formation of a highly reactive activated ester of a β-amino acid which gets cyclised to the corresponding β-lactam in excellent yield. The reaction proceeds smoothly and cleanly as the by-products formed are the water soluble-dimethyl formamide and triethylamine hydrochloride.
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2

Li, Lu, Qiyao Wang, Hui Zhang, Minjun Yang, Mazhar I. Khan та Xiaohui Zhou. "Sensor histidine kinase is a β-lactam receptor and induces resistance to β-lactam antibiotics". Proceedings of the National Academy of Sciences 113, № 6 (2016): 1648–53. http://dx.doi.org/10.1073/pnas.1520300113.

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β-Lactams disrupt bacterial cell wall synthesis, and these agents are the most widely used antibiotics. One of the principle mechanisms by which bacteria resist the action of β-lactams is by producing β-lactamases, enzymes that degrade β-lactams. In Gram-negative bacteria, production of β-lactamases is often induced in response to the antibiotic-associated damage to the cell wall. Here, we have identified a previously unidentified mechanism that governs β-lactamase production. In the Gram-negative enteric pathogenVibrio parahaemolyticus, we found a histidine kinase/response regulator pair (Vbr
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3

Omote, Masaaki, Atsushi Tarui, Masakazu Ueo та ін. "One-Pot Ring-Opening Peptide Synthesis Using α,α-Difluoro-β-Lactams". Synthesis 52, № 23 (2020): 3657–66. http://dx.doi.org/10.1055/s-0040-1707238.

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α,α-Difluoro-β-lactams successfully underwent ring-opening aminolysis with various amino acids in 2,2,2-trifluoroethanol to afford fluorine-containing peptides. In this aminolysis, it was found that 2,2,2-trifluoroethanol first attacked the α,α-difluoro-β-lactams with cleavage of lactam ring to form the corresponding open-chain 2,2,2-trifluoroethyl esters as reactive intermediates. The trifluoroethyl esters were more electrophilic compared with the corresponding methyl ester and thereby accelerated the aminolysis with various amino acids to form β-amino acid peptides with α,α-difluoromethylene
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4

Terada, Tomohiro, Hideyuki Saito, Mayumi Mukai та Ken-Ichi Inui. "Recognition of β-lactam antibiotics by rat peptide transporters, PEPT1 and PEPT2, in LLC-PK1 cells". American Journal of Physiology-Renal Physiology 273, № 5 (1997): F706—F711. http://dx.doi.org/10.1152/ajprenal.1997.273.5.f706.

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PEPT1 and PEPT2 are H+-coupled peptide transporters expressed preferentially in the intestine and kidney, respectively, which mediate uphill transport of oligopeptides and peptide-like drugs such as β-lactam antibiotics. In the present study, we have compared the recognition of β-lactam antibiotics by LLC-PK1 cells stably transfected with PEPT1 or PEPT2 cDNA. Cyclacillin (aminopenicillin) and ceftibuten (anionic cephalosporin without an α-amino group) showed potent inhibitory effects on the glycylsarcosine uptake in the PEPT1-expressing cells. Other β-lactams, such as cephalexin, cefadroxil, a
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5

Skoglund, Erik, Henrietta Abodakpi, Rafael Rios, et al. "In Vivo Resistance to Ceftolozane/Tazobactam in Pseudomonas aeruginosa Arising by AmpC- and Non-AmpC-Mediated Pathways." Case Reports in Infectious Diseases 2018 (December 23, 2018): 1–4. http://dx.doi.org/10.1155/2018/9095203.

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Two pairs of ceftolozane/tazobactam susceptible/resistant P. aeruginosa were isolated from 2 patients after exposure to β-lactams. The genetic basis of ceftolozane/tazobactam resistance was evaluated, and β-lactam-resistant mechanisms were assessed by phenotypic assays. Whole genome sequencing identified mutations in AmpC including the mutation (V213A) and a deletion of 7 amino acids (P210–G216) in the Ω-loop. Phenotypic assays showed that ceftolozane/tazobactam resistance in the strain with AmpCV213A variant was associated with increased β-lactamase hydrolysis activity. On the other hand, the
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6

LaCuran, Alecander E., Kevin M. Pegg, Eleanor M. Liu та ін. "Elucidating the Role of Residue 67 in IMP-Type Metallo-β-Lactamase Evolution". Antimicrobial Agents and Chemotherapy 59, № 12 (2015): 7299–307. http://dx.doi.org/10.1128/aac.01651-15.

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ABSTRACTAntibiotic resistance in bacteria is ever changing and adapting, as once-novel β-lactam antibiotics are losing their efficacy, primarily due to the production of β-lactamases. Metallo-β-lactamases (MBLs) efficiently inactivate a broad range of β-lactam antibiotics, including carbapenems, and are often coexpressed with other antibacterial resistance factors. The rapid dissemination of MBLs and lack of novel antibacterials pose an imminent threat to global health. In an effort to better counter these resistance-conferring β-lactamases, an investigation of their natural evolution and resu
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7

Wheadon, Michael J., та Craig A. Townsend. "Evolutionary and functional analysis of an NRPS condensation domain integrates β-lactam, ᴅ-amino acid, and dehydroamino acid synthesis". Proceedings of the National Academy of Sciences 118, № 17 (2021): e2026017118. http://dx.doi.org/10.1073/pnas.2026017118.

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Nonribosomal peptide synthetases (NRPSs) are large, multidomain biosynthetic enzymes involved in the assembly-line–like synthesis of numerous peptide natural products. Among these are clinically useful antibiotics including three classes of β-lactams: the penicillins/cephalosporins, the monobactams, and the monocyclic nocardicins, as well as the vancomycin family of glycopeptides and the depsipeptide daptomycin. During NRPS synthesis, peptide bond formation is catalyzed by condensation (C) domains, which couple the nascent peptide with the next programmed amino acid of the sequence. A growing
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8

Remete, Attila Márió, та Loránd Kiss. "Alicyclic β- and γ-Amino Acids: Useful Scaffolds for the Stereocontrolled Access to Amino Acid-Based Carbocyclic Nucleoside Analogs". Molecules 24, № 1 (2019): 161. http://dx.doi.org/10.3390/molecules24010161.

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Stereocontrolled synthesis of some amino acid-based carbocyclic nucleoside analogs containing ring C=C bond has been performed on β- and γ-lactam basis. Key steps were N-arylation of readily available β- or γ-lactam-derived amino ester isomers and amino alcohols with 5-amino-4,6-dichloropyrimidine; ring closure of the formed adduct with HC(OMe)3 and nucleophilic displacement of chlorine with various N-nucleophiles in the resulting 6-chloropurine moiety.
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9

Guérin, François, Christophe Isnard, Vincent Cattoir та Jean Christophe Giard. "Complex Regulation Pathways of AmpC-Mediated β-Lactam Resistance in Enterobacter cloacae Complex". Antimicrobial Agents and Chemotherapy 59, № 12 (2015): 7753–61. http://dx.doi.org/10.1128/aac.01729-15.

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ABSTRACTEnterobacter cloacaecomplex (ECC), an opportunistic pathogen causing numerous infections in hospitalized patients worldwide, is able to resist β-lactams mainly by producing the AmpC β-lactamase enzyme. AmpC expression is highly inducible in the presence of some β-lactams, but the underlying genetic regulation, which is intricately linked to peptidoglycan recycling, is still poorly understood. In this study, we constructed different mutant strains that were affected in genes encoding enzymes suspected to be involved in this pathway. As expected, the inactivation ofampC,ampR(which encode
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10

Wachino, Jun-ichi, Yoshihiro Yamaguchi, Shigetarou Mori, Hiromasa Kurosaki, Yoshichika Arakawa та Keigo Shibayama. "Structural Insights into the Subclass B3 Metallo-β-Lactamase SMB-1 and the Mode of Inhibition by the Common Metallo-β-Lactamase Inhibitor Mercaptoacetate". Antimicrobial Agents and Chemotherapy 57, № 1 (2012): 101–9. http://dx.doi.org/10.1128/aac.01264-12.

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ABSTRACTA novel subclass B3 metallo-β-lactamase (MBL), SMB-1, recently identified from aSerratia marcescensclinical isolate, showed a higher hydrolytic activity against a wide range of β-lactams than did the other subclass B3 MBLs, i.e., BJP-1 and FEZ-1, from environmental bacteria. To identify the mechanism underlying the differences in substrate specificity among the subclass B3 MBLs, we determined the structure of SMB-1, using 1.6-Å diffraction data. Consequently, we found that SMB-1 reserves a space in the active site to accommodate β-lactam, even with a bulky R1 side chain, due to a loss
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11

Hujer, Andrea M., Malgosia Kania, Thomas Gerken та ін. "Structure-Activity Relationships of Different β-Lactam Antibiotics against a Soluble Form of Enterococcus faecium PBP5, a Type II Bacterial Transpeptidase". Antimicrobial Agents and Chemotherapy 49, № 2 (2005): 612–18. http://dx.doi.org/10.1128/aac.49.2.612-618.2005.

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ABSTRACT Penicillin-binding proteins (PBPs) catalyze the essential reactions in the biosynthesis of cell wall peptidoglycan from glycopeptide precursors. β-Lactam antibiotics normally interfere with this process by reacting covalently with the active site serine to form a stable acyl-enzyme. The design of novel β-lactams active against penicillin-susceptible and penicillin-resistant organisms will require a better understanding of the molecular details of this reaction. To that end, we compared the affinities of different β-lactam antibiotics to a modified soluble form of a resistant Enterococ
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12

Sarkar, Sujoy Kumar, Mouparna Dutta, Chiranjit Chowdhury, Akash Kumar та Anindya S. Ghosh. "PBP5, PBP6 and DacD play different roles in intrinsic β-lactam resistance of Escherichia coli". Microbiology 157, № 9 (2011): 2702–7. http://dx.doi.org/10.1099/mic.0.046227-0.

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Escherichia coli PBP5, PBP6 and DacD, encoded by dacA, dacC and dacD, respectively, share substantial amino acid identity and together constitute ~50 % of the total penicillin-binding proteins of E. coli. PBP5 helps maintain intrinsic β-lactam resistance within the cell. To test if PBP6 and DacD play simlar roles, we deleted dacC and dacD individually, and dacC in combination with dacA, from E. coli 2443 and compared β-lactam sensitivity of the mutants and the parent strain. β-Lactam resistance was complemented by wild-type, but not dd-carboxypeptidase-deficient PBP5, confirming that enzymic a
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13

Frlan, Rok, Martina Hrast та Stanislav Gobec. "Application of the N-Dibenzyl Protective Group in the Preparation of β-Lactam Pseudopeptides". Molecules 24, № 7 (2019): 1261. http://dx.doi.org/10.3390/molecules24071261.

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Despite the great importance of β-lactam antibiotics, there is still a limited number of synthetic approaches for the formation of β-lactam–containing dipeptides. In this study, we report upon the stereoselective preparation of β-lactam–containing pseudopeptides, where different reaction conditions and NH2 protective groups were tested to obtain compounds that contain 3-amino-azetidin-2-one. We demonstrate that the protective group is essential for the outcome of the reaction. Successful implementation of dibenzyl-protected serine-containing dipeptides through the Mitsunobu reaction can provid
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14

Zhang, Ying, Qiyu Bao, Luc A. Gagnon та ін. "ampG Gene of Pseudomonas aeruginosa and Its Role in β-Lactamase Expression". Antimicrobial Agents and Chemotherapy 54, № 11 (2010): 4772–79. http://dx.doi.org/10.1128/aac.00009-10.

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ABSTRACT In enterobacteria, the ampG gene encodes a transmembrane protein (permease) that transports 1,6-GlcNAc-anhydro-MurNAc and the 1,6-GlcNAc-anhydro-MurNAc peptide from the periplasm to the cytoplasm, which serve as signal molecules for the induction of ampC β-lactamase. The role of AmpG as a transporter is also essential for cell wall recycling. Pseudomonas aeruginosa carries two AmpG homologues, AmpG (PA4393) and AmpGh1 (PA4218), with 45 and 41% amino acid sequence identity, respectively, to Escherichia coli AmpG, while the two homologues share only 19% amino acid identity. In P. aerugi
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15

Girlich, Delphine, Thierry Naas та Patrice Nordmann. "OXA-60, a Chromosomal, Inducible, and Imipenem-Hydrolyzing Class D β-Lactamase from Ralstonia pickettii". Antimicrobial Agents and Chemotherapy 48, № 11 (2004): 4217–25. http://dx.doi.org/10.1128/aac.48.11.4217-4225.2004.

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ABSTRACT A chromosomally encoded oxacillinase, OXA-22, had been characterized from Ralstonia pickettii PIC-1 that did not explain by itself the resistance profile of this strain to β-lactams. Thus, further analysis of the genetic background of this species led to the identification of another oxacillinase, OXA-60, that was expressed only after β-lactam induction. This chromosomally encoded oxacillinase shared 19% amino acid identity with OXA-22. It has a narrow-spectrum hydrolysis profile that includes imipenem. OXA-60-like enzymes were identified in several R. pickettii strains. Gene inactiva
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16

Kiss, Loránd, Enikő Forró, and Ferenc Fülöp. "Novel stereocontrolled syntheses of tashiromine and epitashiromine." Beilstein Journal of Organic Chemistry 11 (April 30, 2015): 596–603. http://dx.doi.org/10.3762/bjoc.11.66.

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A novel stereocontrolled approach has been developed for the syntheses of tashiromine and epitashiromine alkaloids from cyclooctene β-amino acids. The synthetic concept is based on the azetidinone opening of a bicyclic β-lactam, followed by oxidative ring opening through ring C–C double bond and reductive ring-closure reactions of the cis- or trans-cyclooctene β-amino acids.
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17

Polderman-Tijmes, Jolanda J., Peter A. Jekel, Erik J. de Vries та ін. "Cloning, Sequence Analysis, and Expression in Escherichia coli of the Gene Encoding an α-Amino Acid Ester Hydrolase from Acetobacter turbidans". Applied and Environmental Microbiology 68, № 1 (2002): 211–18. http://dx.doi.org/10.1128/aem.68.1.211-218.2002.

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ABSTRACT The α-amino acid ester hydrolase from Acetobacter turbidans ATCC 9325 is capable of hydrolyzing and synthesizing β-lactam antibiotics, such as cephalexin and ampicillin. N-terminal amino acid sequencing of the purified α-amino acid ester hydrolase allowed cloning and genetic characterization of the corresponding gene from an A. turbidans genomic library. The gene, designated aehA, encodes a polypeptide with a molecular weight of 72,000. Comparison of the determined N-terminal sequence and the deduced amino acid sequence indicated the presence of an N-terminal leader sequence of 40 ami
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18

Beceiro, Alejandro, Astrid Pérez, Felipe Fernández-Cuenca, et al. "Genetic Variability among ampC Genes from Acinetobacter Genomic Species 3." Antimicrobial Agents and Chemotherapy 53, no. 3 (2008): 1177–84. http://dx.doi.org/10.1128/aac.00485-08.

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ABSTRACT As a part of a nationwide study in Spain, 15 clinical isolates of Acinetobacter genomic species 3 (AG3) were analyzed. The main objective of the study was to characterize the ampC genes from these isolates and to determine their involvement in β-lactam resistance in AG3. The 15 AG3 isolates showed different profiles of resistance to ampicillin (range of MICs, 12 to >256 μg/ml). Nucleotide sequencing of the 15 ampC genes yielded 12 new AmpC enzymes (ADC-12 to ADC-23). The 12 AG3 enzymes showed 93.7 to 96.1% amino acid identity with respect to the AmpC enzyme from Acinetobacter bauma
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19

Núñez-Villanueva, Diego, M. Teresa García-López, Mercedes Martín-Martínez та Rosario González-Muñiz. "Divergent, stereoselective access to heterocyclic α,α-quaternary- and β2,3,3-amino acid derivatives from a N-Pmp-protected Orn-derived β-lactam". Organic & Biomolecular Chemistry 13, № 18 (2015): 5195–201. http://dx.doi.org/10.1039/c5ob00429b.

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20

Khan, Ayesha, Razieh Kebriaei, Kavindra V. Singh,, Barbara E. Murray, Michael J. Rybak та Cesar A. Arias. "615. Daptomycin (DAP) Synergy with β-Lactams in DAP-Resistant (DAP-R) E. faecium (Efm) Is Dependent On PBP5 Sequence and β-Lactam-binding Affinity". Open Forum Infectious Diseases 6, Supplement_2 (2019): S287. http://dx.doi.org/10.1093/ofid/ofz360.683.

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Abstract Background DAP in combination with β-lactams is a viable option to treat recalcitrant DAP-R/tolerant strains of Efm. Ampicillin (AMP), ceftaroline (CPT), and ertapenem (ERT) have the best synergism. Using a DAP tolerant strain (503; DAP MIC 2 µg/mL) of Efm, we previously showed that AMP, CPT, and ERT combined with DAP were effective in reducing bacterial loads and prevented emergence of resistance in a simulated endocardial vegetation model. However, against a DAP-R Efm strain (R497, DAP MIC of 16 µg/mL), CPT, ERT failed to synergize with DAP. Here, we dissect the mechanistic basis of
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21

Osaki, Yumi, Yumiko Sanbongi, Midori Ishikawa та ін. "Genetic Approach To Study the Relationship between Penicillin-Binding Protein 3 Mutations and Haemophilus influenzae β-Lactam Resistance by Using Site-Directed Mutagenesis and Gene Recombinants". Antimicrobial Agents and Chemotherapy 49, № 7 (2005): 2834–39. http://dx.doi.org/10.1128/aac.49.7.2834-2839.2005.

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ABSTRACT To clarify the relationship between mutations commonly found for penicillin-binding protein 3 (PBP 3) of β-lactamase-nonproducing ampicillin-resistant (BLNAR) Haemophilus influenzae isolates and β-lactam resistance, single and multiple amino acid mutations at positions 377, 385, 389, 517, and 526 were introduced into PBP 3 of a β-lactam-susceptible Rd strain by site-directed mutagenesis. Twelve isogenic recombinant strains were challenged with nine β-lactam antibiotics. Replacement of the asparagine at position 526 with lysine (N526K) increased the resistance to imipenem eightfold and
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22

Brakhage, Axel A. "Molecular Regulation of β-Lactam Biosynthesis in Filamentous Fungi". Microbiology and Molecular Biology Reviews 62, № 3 (1998): 547–85. http://dx.doi.org/10.1128/mmbr.62.3.547-585.1998.

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SUMMARY The most commonly used β-lactam antibiotics for the therapy of infectious diseases are penicillin and cephalosporin. Penicillin is produced as an end product by some fungi, most notably by Aspergillus (Emericella) nidulans and Penicillium chrysogenum. Cephalosporins are synthesized by both bacteria and fungi, e.g., by the fungus Acremonium chrysogenum (Cephalosporium acremonium). The biosynthetic pathways leading to both secondary metabolites start from the same three amino acid precursors and have the first two enzymatic reactions in common. Penicillin biosynthesis is catalyzed by thr
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23

Ji, Dong-Sheng, Hui Liang, Kai-Xuan Yang та ін. "Solvent directed chemically divergent synthesis of β-lactams and α-amino acid derivatives with chiral isothiourea". Chemical Science 13, № 6 (2022): 1801–7. http://dx.doi.org/10.1039/d1sc06127e.

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24

Ombito, Japheth O., та Girija S. Singh. "Recent Progress in Chemistry of β-Lactams". Mini-Reviews in Organic Chemistry 16, № 6 (2019): 544–67. http://dx.doi.org/10.2174/1570193x15666180914165303.

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The β-lactams constitute a well-known class of compounds having tremendous biological significance. Besides being a motif of biological interest, they serve as versatile synthons in organic chemistry. In fact, their easy accessibility in the laboratory by several methods combined with inherent reactivity of the β -lactam ring due to ring-strain places it among the most sought for substrate in the arsenal of synthetic organic chemists. Several chemical reagents, heat, and light promote its ring-opening, ring-expansions and rearrangement reactions yielding a wide variety of bio
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25

Bachmann, Brian O., Rongfeng Li та Craig A. Townsend. "β-Lactam synthetase: A new biosynthetic enzyme". Proceedings of the National Academy of Sciences 95, № 16 (1998): 9082–86. http://dx.doi.org/10.1073/pnas.95.16.9082.

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The principal cause of bacterial resistance to penicillin and other β-lactam antibiotics is the acquisition of plasmid-encoded β-lactamases, enzymes that catalyze hydrolysis of the β-lactam bond and render these antibiotics inactive. Clavulanic acid is a potent inhibitor of β-lactamases and has proven clinically effective in combating resistant infections. Although clavulanic acid and penicillin share marked structural similarities, the biosyntheses of their bicyclic nuclei are wholly dissimilar. In contrast to the efficient iron-mediated oxidative cyclization of a tripeptide to isopenicillin
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26

Brown, Nicholas G., Lori B. Horton, Wanzhi Huang, Sompong Vongpunsawad та Timothy Palzkill. "Analysis of the Functional Contributions of Asn233 in Metallo-β-Lactamase IMP-1". Antimicrobial Agents and Chemotherapy 55, № 12 (2011): 5696–702. http://dx.doi.org/10.1128/aac.00340-11.

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ABSTRACTMetallo-β-lactamases, such as IMP-1, are a major global health threat, as they provide for bacterial resistance to a wide range of β-lactam antibiotics, including carbapenems. Understanding the molecular details of the enzymatic process and the sequence requirements for function are essential aids in overcoming β-lactamase-mediated resistance. An asparagine residue is conserved at position 233 in approximately 67% of all metallo-β-lactamases. Despite its conservation, the molecular basis of Asn233 function is poorly understood and remains controversial. It has previously been shown tha
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27

Ma, Ling, Yoshikazu Ishii, Masaji Ishiguro, Hiroshi Matsuzawa та Keizo Yamaguchi. "Cloning and Sequencing of the Gene Encoding Toho-2, a Class A β-Lactamase Preferentially Inhibited by Tazobactam". Antimicrobial Agents and Chemotherapy 42, № 5 (1998): 1181–86. http://dx.doi.org/10.1128/aac.42.5.1181.

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ABSTRACT Escherichia coli TUM1083, which is resistant to ampicillin, carbenicillin, cephaloridine, cephalothin, piperacillin, cefuzonam, and aztreonam while being sensitive to cefoxitin, moxalactam, cefmetazole, ceftazidime, and imipenem, was isolated from the urine of a patient treated with β-lactam antibiotics. The β-lactamase (Toho-2) purified from the bacteria hydrolyzed β-lactam antibiotics such as penicillin G, carbenicillin, cephaloridine, cefoxitin, cefotaxime, ceftazidime, and aztreonam and especially had increased relative hydrolysis rates for cephalothin, cephaloridine, cefotaxime,
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28

Virendra, Prasad, Mishra Nidhi, B. Mishra Kunj, Shashi Somesh та K. Tiwari Vinod. "Facile synthesis of glycosyl β-lactam from glycosyl β-amino esters". Journal of Indian Chemical Society Vol. 92, Oct 2015 (2015): 1557–68. https://doi.org/10.5281/zenodo.5700991.

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Department of Chemistry, Faculty of Science, Banaras Hindu University, Varanasi-221 005, Uttar Pradesh, India <em>E-mail</em> : Tiwari_chem@yahoo.co.in Central Institute for Research on Cotton Technology, Matunga, Mumbai-400 019, India <em>Manuscript received online 12 February 2015, accepted 04 March 2015</em> In addition to the wide range of pharmacological activities associated with &beta;-lactams, their importance as synthetic intermediates in organic synthesis has been widely recognized. A series of glycosyl &beta;-lactam of promising chemotherapeutic values has been developed from corres
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29

Palomo, Claudio, Fernando P. Cossío, Gloria Rubiales та Domitila Aparicio. "A β-lactam approach to ψ-amino-β-keto acid derivatives." Tetrahedron Letters 32, № 26 (1991): 3115–18. http://dx.doi.org/10.1016/0040-4039(91)80704-a.

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30

Sampson, Jared M., Wei Ke, Christopher R. Bethel та ін. "Ligand-Dependent Disorder of the Ω Loop Observed in Extended-Spectrum SHV-Type β-Lactamase". Antimicrobial Agents and Chemotherapy 55, № 5 (2011): 2303–9. http://dx.doi.org/10.1128/aac.01360-10.

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ABSTRACTAmong Gram-negative bacteria, resistance to β-lactams is mediated primarily by β-lactamases (EC 3.2.6.5), periplasmic enzymes that inactivate β-lactam antibiotics. Substitutions at critical amino acid positions in the class A β-lactamase families result in enzymes that can hydrolyze extended-spectrum cephalosporins, thus demonstrating an “extended-spectrum” β-lactamase (ESBL) phenotype. Using SHV ESBLs with substitutions in the Ω loop (R164H and R164S) as target enzymes to understand this enhanced biochemical capability and to serve as a basis for novel β-lactamase inhibitor developmen
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31

López-Francés, Adrián, Xabier del Del Corte, Zuriñe Serna-Burgos, Edorta Martínez de Martínez de Marigorta, Francisco Palacios та Javier Vicario. "Exploring the Synthetic Potential of γ-Lactam Derivatives Obtained from a Multicomponent Reaction. Applications as Antiproliferative Agents". Molecules 27, № 11 (2022): 3624. http://dx.doi.org/10.3390/molecules27113624.

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A study on the reactivity of 3-amino α,β-unsaturated γ-lactam derivatives obtained from a multicomponent reaction is presented. Key features of the substrates are the presence of an endocyclic α,β-unsaturated amide moiety and an enamine functionality. Following different synthetic protocols, the functionalization at three different positions of the lactam core is achieved. In the presence of a soft base, under thermodynamic conditions, the functionalization at C-4 takes place where the substrates behave as enamines, while the use of a strong base, under kinetic conditions, leads to the formati
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32

Franceschini, Nicola, Berardo Caravelli, Jean-Denis Docquier та ін. "Purification and Biochemical Characterization of the VIM-1 Metallo-β-Lactamase". Antimicrobial Agents and Chemotherapy 44, № 11 (2000): 3003–7. http://dx.doi.org/10.1128/aac.44.11.3003-3007.2000.

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ABSTRACT VIM-1 is a new group 3 metallo-β-lactamase recently detected in carbapenem-resistant nosocomial isolates of Pseudomonas aeruginosa from the Mediterranean area. In this work, VIM-1 was purified from an Escherichia coli strain carrying the cloned bla VIM-1 gene by means of an anion-exchange chromatography step followed by a gel permeation chromatography step. The purified enzyme exhibited a molecular mass of 26 kDa in sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and an acidic pI of 5.1 in analytical isoelectric focusing. Amino-terminal sequencing showed that mature VIM-1 r
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33

Trépanier, Sonia, James R. Knox, Natalie Clairoux, François Sanschagrin, Roger C. Levesque та Ann Huletsky. "Structure-Function Studies of Ser-289 in the Class C β-Lactamase from Enterobacter cloacae P99". Antimicrobial Agents and Chemotherapy 43, № 3 (1999): 543–48. http://dx.doi.org/10.1128/aac.43.3.543.

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ABSTRACT Site-directed mutagenesis of Ser-289 of the class C β-lactamase from Enterobacter cloacae P99 was performed to investigate the role of this residue in β-lactam hydrolysis. This amino acid lies near the active site of the enzyme, where it can interact with the C-3 substituent of cephalosporins. Kinetic analysis of six mutant β-lactamases with five cephalosporins showed that Ser-289 can be substituted by amino acids with nonpolar or polar uncharged side chains without altering the catalytic efficiency of the enzyme. These data suggest that Ser-289 is not essential in the binding or hydr
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34

Yasir F. Muhsin, Shakir M. Alwan, and Ayad Kareem Khan. "Design, Molecular Docking, Synthesis of Aromatic Amino Acids Linked to Cephalexin." Al Mustansiriyah Journal of Pharmaceutical Sciences 21, no. 3 (2022): 25–34. http://dx.doi.org/10.32947/ajps.v21i3.794.

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Infections caused by bacteria have a significant impact on public health. Chemical synthesis of new derivatives of cephalexin inked to amino acid (tryptophan or histidine) through an amide bond at the acyl side chain is achieved. This is a new&#x0D; approach of incorporating, tryptophan and histidine into the the primary amino group of cephalexin, in order to provide a bulky group very close to the β-lactam ring. This chemical addition act as isosteric group to the alkoximino that protect beta lactam ring from bacterial beta lactamase enzyme. The new derivatives may show resistance to β-lactam
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35

Langaee, Taimour Yousef, Luc Gagnon та Ann Huletsky. "Inactivation of the ampD Gene inPseudomonas aeruginosa Leads to Moderate-Basal-Level and Hyperinducible AmpC β-Lactamase Expression". Antimicrobial Agents and Chemotherapy 44, № 3 (2000): 583–89. http://dx.doi.org/10.1128/aac.44.3.583-589.2000.

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ABSTRACT It has been shown in enterobacteria that mutations inampD provoke hyperproduction of chromosomal β-lactamase, which confers to these organisms high levels of resistance to β-lactam antibiotics. In this study, we investigated whether this genetic locus was implicated in the altered AmpC β-lactamase expression of selected clinical isolates and laboratory mutants ofPseudomonas aeruginosa. The sequences of theampD genes and promoter regions from these strains were determined and compared to that of wild-type ampD fromP. aeruginosa PAO1. Although we identified numerous nucleotide substitut
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36

Townsend, Craig A. "Oxidative amino aid processing in β-lactam antibiotic biosynthesis". Biochemical Society Transactions 21, № 1 (1993): 208–13. http://dx.doi.org/10.1042/bst0210208.

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37

Poirel, Laurent, Vincent Cattoir, Ana Soares, Claude-James Soussy та Patrice Nordmann. "Novel Ambler Class A β-Lactamase LAP-1 and Its Association with the Plasmid-Mediated Quinolone Resistance Determinant QnrS1". Antimicrobial Agents and Chemotherapy 51, № 2 (2006): 631–37. http://dx.doi.org/10.1128/aac.01082-06.

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ABSTRACT The plasmid-mediated quinolone resistance determinant QnrS1 was identified in non-clonally related Enterobacter cloacae isolates in association with a transferable narrow-spectrum β-lactam resistance marker. Cloning experiments allowed the identification of a novel Ambler class A β-lactamase, named LAP-1. It shares 62 and 61% amino acid identity with the most closely related β-lactamases, TEM-1 and SHV-1, respectively. It has a narrow-spectrum hydrolysis of β-lactams and is strongly inhibited by clavulanic acid and sulbactam and, to a lesser extent, by tazobactam. Association of the b
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38

Patel, Ila T., Muljibhai B. Devani, and Tushar M. Patel. "Spectrophotometric Method for Determination of Cephalexin in Its Dosage Forms." Journal of AOAC INTERNATIONAL 75, no. 6 (1992): 994–98. http://dx.doi.org/10.1093/jaoac/75.6.994.

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Abstract A simple, rapid, and specific method was developed for determination of cephalexin and its dosage forms. The method is based on the reaction of cephalexin with acetylacetone-formaldehyde reagent to give a yellow chromophore measurable at 400 nm. The color is stable for 3 h. Beer's law is valid within a concentration range of 10-100 μg/mL for cephalexin. All variables were studied to optimize the reaction conditions. The method is specific for amino β-lactam antibiotics. Non-amino β-lactam antibiotics do not interfere. No interference was observed in the presence of common pharmaceutic
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39

Yang, Hao, та Michael W. Crowder. "New Delhi metallo-β-lactamase (NDM)". Biochemist 37, № 3 (2015): 18–21. http://dx.doi.org/10.1042/bio03703018.

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Metallo-β-lactamases (MBLs) are a class of Zn(II)-containing enzymes that hydrolyse the β-lactam bond in β-lactam-containing antibiotics, resulting in products that no longer exhibit antibacterial activity. Currently, there are 29 known MBLs (not including variants), and these enzymes have been classified on the basis of primary amino acid sequence and functionality into three or four classes (see www.mbled.uni-stuttgart.de for an updated MBL database)1. MBLs in classes B1 and B3 are known for their ability to hydrolyse all β-lactam antibiotics, except monobactams, including penicillins, carba
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40

Angelaud, Rémy, Yong-Li Zhong, Peter Maligres, Jaemoon Lee та David Askin. "Synthesis of a β-Amino Acid Pharmacophore via a β-Lactam Intermediate". Journal of Organic Chemistry 70, № 5 (2005): 1949–52. http://dx.doi.org/10.1021/jo048249c.

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41

Jeon, Jeong Ho, Soo-Jin Kim, Hyun Sook Lee та ін. "Novel Metagenome-Derived Carboxylesterase That Hydrolyzes β-Lactam Antibiotics". Applied and Environmental Microbiology 77, № 21 (2011): 7830–36. http://dx.doi.org/10.1128/aem.05363-11.

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ABSTRACTIt has been proposed that family VIII carboxylesterases and class C β-lactamases are phylogenetically related; however, none of carboxylesterases has been reported to hydrolyze β-lactam antibiotics except nitrocefin, a nonclinical chromogenic substrate. Here, we describe the first example of a novel carboxylesterase derived from a metagenome that is able to cleave the amide bond of various β-lactam substrates and the ester bond ofp-nitrophenyl esters. A clone with lipolytic activity was selected by functional screening of a metagenomic library using tributyrin agar plates. The sequence
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42

Pradel, N., J. Delmas, L. F. Wu, C. L. Santini та R. Bonnet. "Sec- and Tat-Dependent Translocation of β-Lactamases across the Escherichia coli Inner Membrane". Antimicrobial Agents and Chemotherapy 53, № 1 (2008): 242–48. http://dx.doi.org/10.1128/aac.00642-08.

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ABSTRACT β-Lactamases represent the major resistance mechanism of gram-negative bacteria against β-lactam antibiotics. The amino acid sequences of these proteins vary widely, but all are located in the periplasm of bacteria. In this study, we investigated the translocation mechanism of representative β-lactamases in an Escherichia coli model. N-terminal signal sequence analyses, antibiotic activity assay, and direct measurement of translocation of a green fluorescent protein (GFP) reporter fused to β-lactamases revealed that most were exported via the Sec pathway. However, the Stenotrophomonas
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43

Neamah, Rawaa, та Shaimaa Adnan. "Study the Biological Activity for Shiff Base and Β – Lactam Compounds that Synthesis and Identification from Pyrimidine Derivatives". International Journal of Pharmaceutical Quality Assurance 11, № 01 (2013): 37–39. http://dx.doi.org/10.25258/ijpqa.11.1.12.

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In This study We are synthesis and characterization of some Schiff base and β- lactam derivatives) by three steps. The First react 2-amino-4-Chloro-6-methyl pyrimidine with 4-amino acetophenone in an acid medium to get shiff base derivative(E)-4-(1-((4-Chloro-6-methyl pyridine-2-yl)imino)ethyl)aniline (1), the second step (1) react with (3,4- dimethoxybenzal dehyde,4-methyl benzaldehyde,4-dimethylamino benzaldehyde,4-bromo benzaldehyde,4–hydroxy benzaldehyde, 4-Nitro benzaldehyde) to get Schiff base derivatives (2-7), the last step (2-7) derivatives react with Chloro acetyl chloride to get –β-
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44

Pagliero, Estelle, Laurent Chesnel, Julie Hopkins та ін. "Biochemical Characterization of Streptococcus pneumoniae Penicillin-Binding Protein 2b and Its Implication in β-Lactam Resistance". Antimicrobial Agents and Chemotherapy 48, № 5 (2004): 1848–55. http://dx.doi.org/10.1128/aac.48.5.1848-1855.2004.

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ABSTRACT Extensive use of β-lactam antibiotics has led to the selection of pathogenic streptococci resistant to β-lactams due to modifications of the penicillin-binding proteins (PBPs). PBP2b from Streptococcus pneumoniae is a monofunctional (class B) high-molecular-weight PBP catalyzing the transpeptidation between adjacent stem peptides of peptidoglycan. The transpeptidase domain of PBP2b isolated from seven clinical resistant (CR) strains contains 7 to 44 amino acid changes over the sequence of PBP2b from the R6 β-lactam-sensitive strain. We show that the extracellular soluble domains of re
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45

Peters, Katharina, Manuel Pazos, Zainab Edoo та ін. "Copper inhibits peptidoglycan LD-transpeptidases suppressing β-lactam resistance due to bypass of penicillin-binding proteins". Proceedings of the National Academy of Sciences 115, № 42 (2018): 10786–91. http://dx.doi.org/10.1073/pnas.1809285115.

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The peptidoglycan (PG) layer stabilizes the bacterial cell envelope to maintain the integrity and shape of the cell. Penicillin-binding proteins (PBPs) synthesize essential 4–3 cross-links in PG and are inhibited by β-lactam antibiotics. Some clinical isolates and laboratory strains ofEnterococcus faeciumandEscherichia coliachieve high-level β-lactam resistance by utilizing β-lactam–insensitive LD-transpeptidases (LDTs) to produce exclusively 3–3 cross-links in PG, bypassing the PBPs. InE. coli, other LDTs covalently attach the lipoprotein Lpp to PG to stabilize the envelope and maintain the p
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46

Trip, Hein, Melchior E. Evers, Jan A. K. W. Kiel та Arnold J. M. Driessen. "Uptake of the β-Lactam Precursor α-Aminoadipic Acid in Penicillium chrysogenum Is Mediated by the Acidic and the General Amino Acid Permease". Applied and Environmental Microbiology 70, № 8 (2004): 4775–83. http://dx.doi.org/10.1128/aem.70.8.4775-4783.2004.

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ABSTRACT External addition of the β-lactam precursor α-aminoadipic acid to the filamentous fungus Penicillium chrysogenum leads to an increased intracellular α-aminoadipic acid concentration and an increase in penicillin production. The exact route for α-aminoadipic acid uptake is not known, although the general amino acid and acidic amino acid permeases have been implicated in this process. Their corresponding genes, PcGAP1 and PcDIP5, of P. chrysogenum were cloned and functionally expressed in a mutant of Saccharomyces cerevisiae (M4276) in which the acidic amino acid and general amino acid
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47

Palomo, Claudio, Mikel Oiarbide та Simona Bindi. "A Concise β-Lactam Route to Short Peptide Segments Containing β,β-Disubstituted β-Amino Acids". Journal of Organic Chemistry 63, № 8 (1998): 2469–74. http://dx.doi.org/10.1021/jo9712862.

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48

Dražić, Tonko, Krešimir Molčanov, Vinay Sachdev та ін. "Novel amino-β-lactam derivatives as potent cholesterol absorption inhibitors". European Journal of Medicinal Chemistry 87 (листопад 2014): 722–34. http://dx.doi.org/10.1016/j.ejmech.2014.10.014.

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49

Ambrosi, Horst-Dieter, Annamarie Kunath та Klaus Jähnisch. "β-Lactame und β-Lactam-Zwischenprodukte, 2. Mitt.: Stereoselektive Synthese voncis-3-Amino-1,4-diphenyl-azetidin-2-on". Archiv der Pharmazie 326, № 6 (1993): 319–21. http://dx.doi.org/10.1002/ardp.19933260603.

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50

De, Chang Woo Kim, Young Chung Bong, Namkung Ja-Young, Moon Lee Joo та Kim Sunggak. "New methods for β-lactam formation from β-amino acids with organophosphorous compounds". Tetrahedron Letters 31, № 20 (1990): 2905–6. http://dx.doi.org/10.1016/0040-4039(90)80180-t.

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