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Journal of Enzyme Inhibition and... Dec 2017Beta-Lactamase Database (BLDB) is a comprehensive, manually curated public resource providing up-to-date structural and functional information focused on this...
Beta-Lactamase Database (BLDB) is a comprehensive, manually curated public resource providing up-to-date structural and functional information focused on this superfamily of enzymes with a great impact on antibiotic resistance. All the enzymes reported and characterised in the literature are presented according to the class (A, B, C and D), family and subfamily to which they belong. All three-dimensional structures of β-lactamases present in the Protein Data Bank are also shown. The characterisation of representative mutants and hydrolytic profiles (kinetics) completes the picture and altogether these four elements constitute the essential foundation for a better understanding of the structure-function relationship within this enzymes family. BLDB can be queried using different protein- and nucleotide-based BLAST searches, which represents a key feature of particular importance in the context of the surveillance of the evolution of the antibiotic resistance. BLDB is available online at http://bldb.eu without any registration and supports all modern browsers.
Topics: Databases, Protein; Protein Conformation; beta-Lactamases
PubMed: 28719998
DOI: 10.1080/14756366.2017.1344235 -
Emerging Infectious Diseases Jan 2022
Topics: Klebsiella pneumoniae; beta-Lactamases
PubMed: 34932454
DOI: 10.3201/eid2801.212106 -
Antimicrobial Agents and Chemotherapy Dec 2019causes severe antibiotic-associated diarrhea and colitis. is an anaerobic, Gram-positive sporeformer that is highly resistant to β-lactams, the most commonly...
causes severe antibiotic-associated diarrhea and colitis. is an anaerobic, Gram-positive sporeformer that is highly resistant to β-lactams, the most commonly prescribed antibiotics. The resistance of to β-lactam antibiotics allows the pathogen to replicate and cause disease in antibiotic-treated patients. However, the mechanisms of β-lactam resistance in are not fully understood. Our data reinforce prior evidence that produces a β-lactamase, which is a common β-lactam resistance mechanism found in other bacterial species. Here, we characterize the operon that encodes a lipoprotein of unknown function and a β-lactamase that was greatly induced in response to several classes of β-lactam antibiotics. An in-frame deletion of the operon abolished β-lactamase activity in strain 630Δ and resulted in decreased resistance to the β-lactam ampicillin. We found that the activity of this β-lactamase, BlaCDD, is dependent upon the redox state of the enzyme. In addition, we observed that transport of BlaCDD out of the cytosol and to the cell surface is facilitated by an N-terminal signal sequence. Our data demonstrate that a cotranscribed lipoprotein, BlaX, aids in BlaCDD activity. Further, we identified a conserved BlaRI regulatory system and demonstrated via insertional disruption that BlaRI controls transcription of the genes in response to β-lactams. These results provide support for the function of a β-lactamase in antibiotic resistance and reveal the unique roles of a coregulated lipoprotein and reducing environment in β-lactamase activity.
Topics: Anaerobiosis; Bacterial Proteins; Clostridioides difficile; Drug Resistance, Microbial; Lipoproteins; beta-Lactamases; beta-Lactams
PubMed: 31611350
DOI: 10.1128/AAC.01496-19 -
Antimicrobial Agents and Chemotherapy Jun 2022β-Lactam antibiotics are the first choice for the treatment of most bacterial infections. However, the increased prevalence of β-lactamases, in particular...
β-Lactam antibiotics are the first choice for the treatment of most bacterial infections. However, the increased prevalence of β-lactamases, in particular extended-spectrum β-lactamases, in pathogenic bacteria has severely limited the possibility of using β-lactam treatments. Combining β-lactam antibiotics with β-lactamase inhibitors can restore treatment efficacy by negating the effect of the β-lactamase and has become increasingly important against infections caused by β-lactamase-producing strains. Not surprisingly, bacteria with resistance to even these combinations have been found in patients. Studies on the development of bacterial resistance to β-lactam/β-lactamase inhibitor combinations have focused mainly on the effects of single, chromosomal or plasmid-borne, β-lactamases. However, clinical isolates often carry more than one β-lactamase in addition to multiple other resistance genes. Here, we investigate how the evolutionary trajectories of the development of resistance to three commonly used β-lactam/β-lactamase inhibitor combinations, ampicillin-sulbactam, piperacillin-tazobactam, and ceftazidime-avibactam, were affected by the presence of three common β-lactamases, TEM-1, CTX-M-15, and OXA-1. First-step resistance was due mainly to extensive gene amplifications of one or several of the β-lactamase genes where the amplification pattern directly depended on the respective drug combination. Amplifications also served as a stepping-stone for high-level resistance in combination with additional mutations that reduced drug influx or mutations in the β-lactamase gene . This illustrates that the evolutionary trajectories of resistance to β-lactam/β-lactamase inhibitor combinations are strongly influenced by the frequent and transient nature of gene amplifications and how the presence of multiple β-lactamases shapes the evolution to higher-level resistance.
Topics: Anti-Bacterial Agents; Escherichia coli; Humans; Lactams; Microbial Sensitivity Tests; Monobactams; Piperacillin, Tazobactam Drug Combination; beta-Lactamase Inhibitors; beta-Lactamases
PubMed: 35652643
DOI: 10.1128/aac.00290-22 -
Trends in Pharmacological Sciences Jul 2018Metallo-β-lactamases (MBLs) are a significant clinical problem because they hydrolyze and inactivate nearly all β-lactam-containing antibiotics. These 'lifesaving... (Review)
Review
Metallo-β-lactamases (MBLs) are a significant clinical problem because they hydrolyze and inactivate nearly all β-lactam-containing antibiotics. These 'lifesaving drugs' constitute >50% of the available contemporary antibiotic arsenal. Despite the global spread of MBLs, MBL inhibitors have not yet appeared in clinical trials. Most MBL inhibitors target active site zinc ions and vary in mechanism from ternary complex formation to metal ion stripping. Importantly, differences in mechanism can impact pharmacology in terms of reversibility, target selectivity, and structure-activity relationship interpretation. This review surveys the mechanisms of MBL inhibitors and describes methods that determine the mechanism of inhibition to guide development of future therapeutics.
Topics: Animals; Anti-Bacterial Agents; Bacterial Proteins; Catalytic Domain; Drug Resistance, Microbial; Humans; Models, Molecular; Structure-Activity Relationship; beta-Lactamase Inhibitors; beta-Lactamases
PubMed: 29680579
DOI: 10.1016/j.tips.2018.03.007 -
Current Opinion in Structural Biology Oct 2018Beta-lactamase enzymes mediate the most common forms of gram-negative antibiotic resistance affecting clinical treatment. They also constitute an excellent model system... (Review)
Review
Beta-lactamase enzymes mediate the most common forms of gram-negative antibiotic resistance affecting clinical treatment. They also constitute an excellent model system for the difficult problem of understanding how allosteric mutations can augment catalytic activity of already-competent enzymes. Multiple allosteric mutations have been identified that alter catalytic activity or drug-resistance spectrum in class A beta lactamases, but predicting these in advance continues to be challenging. Here, we review computational techniques based on structure and/or molecular simulation to predict such mutations. Structure-based techniques have been particularly helpful in developing graph algorithms for analyzing critical residues in beta-lactamase function, while classical molecular simulation has recently shown the ability to prospectively predict allosteric mutations increasing beta-lactamase activity and drug resistance. These will ultimately achieve the greatest power when combined with simulation methods that model reactive chemistry to calculate activation free energies directly.
Topics: Allosteric Regulation; Anti-Bacterial Agents; Bacterial Proteins; Catalysis; Drug Resistance, Microbial; Humans; Models, Molecular; Molecular Docking Simulation; Molecular Dynamics Simulation; Molecular Structure; Mutation; Structure-Activity Relationship; beta-Lactamases
PubMed: 30243041
DOI: 10.1016/j.sbi.2018.09.001 -
Antimicrobial Agents and Chemotherapy Sep 2020Class A β-lactamases are a major cause of β-lactam resistance in Gram-negative bacteria. The recently FDA-approved cyclic boronate vaborbactam is a reversible covalent...
Class A β-lactamases are a major cause of β-lactam resistance in Gram-negative bacteria. The recently FDA-approved cyclic boronate vaborbactam is a reversible covalent inhibitor of class A β-lactamases, including CTX-M extended-spectrum β-lactamase and KPC carbapenemase, both frequently observed in the clinic. Intriguingly, vaborbactam displayed different binding kinetics and cell-based activity for these two enzymes, despite their similarity. A 1.0-Å crystal structure of CTX-M-14 demonstrated that two catalytic residues, K73 and E166, are positively charged and neutral, respectively. Meanwhile, a 1.25-Å crystal structure of KPC-2 revealed a more compact binding mode of vaborbactam versus CTX-M-14, as well as alternative conformations of W105. Together with kinetic analysis of W105 mutants, the structures demonstrate the influence of this residue and the unusual conformation of the β3 strand on the inactivation rate, as well as the stability of the reversible covalent bond with S70. Furthermore, studies of KPC-2 S130G mutant shed light on the different impacts of S130 in the binding of vaborbactam versus avibactam, another recently approved β-lactamase inhibitor. Taken together, these new data provide valuable insights into the inhibition mechanism of vaborbactam and future development of cyclic boronate inhibitors.
Topics: Anti-Bacterial Agents; Boronic Acids; Kinetics; beta-Lactamase Inhibitors; beta-Lactamases
PubMed: 32778546
DOI: 10.1128/AAC.00398-20 -
ACS Infectious Diseases Apr 2019With the widespread use and abuse of antibiotics for the past decades, antimicrobial resistance poses a serious threat to public health nowadays. β-Lactams are the most...
With the widespread use and abuse of antibiotics for the past decades, antimicrobial resistance poses a serious threat to public health nowadays. β-Lactams are the most used antibiotics, and β-lactamases are the most widespread resistance mechanism. Class C β-lactamases, also known as cephalosporinases, usually do not hydrolyze the latest and most potent β-lactams, expanded spectrum cephalosporins and carbapenems. However, the recent emergence of extended-spectrum AmpC cephalosporinases, their resistance to inhibition by classic β-lactamase inhibitors, and the fact that they can contribute to carbapenem resistance when paired with impermeability mechanisms, means that these enzymes may still prove worrisome in the future. Here we report and characterize the CMY-136 β-lactamase, a Y221H point mutant derivative of CMY-2. CMY-136 confers an increased level of resistance to ticarcillin, cefuroxime, cefotaxime, and ceftolozane/tazobactam. It is also capable of hydrolyzing ticarcillin and cloxacillin, which act as inhibitors of CMY-2. X-ray crystallography and modeling experiments suggest that the hydrolytic profile alterations seem to be the result of an increased flexibility and altered conformation of the Ω-loop, caused by the Y221H mutation.
Topics: Anti-Bacterial Agents; Escherichia coli; Escherichia coli Proteins; Microbial Sensitivity Tests; Mutation, Missense; beta-Lactamase Inhibitors; beta-Lactamases
PubMed: 30788955
DOI: 10.1021/acsinfecdis.8b00240 -
Cells Sep 2022Serine beta-lactamase-like protein (LACTB) is the only mammalian mitochondrial homolog evolved from penicillin-binding proteins and β-lactamases (PBP-βLs) in bacteria....
Serine beta-lactamase-like protein (LACTB) is the only mammalian mitochondrial homolog evolved from penicillin-binding proteins and β-lactamases (PBP-βLs) in bacteria. LACTB, an active-site serine protease, polymerizes into stable filaments, which are localized to the intermembrane space (IMS) of mitochondrion and involved in the submitochondrial organization, modulating mitochondrial lipid metabolism. Cancer pathogenesis and progression are relevant to the alterations in mitochondrial metabolism. Metabolic reprogramming contributes to cancer cell behavior. This article (1) evidences the clinical implications of LACTB on neoplastic cell proliferation and migration and tumor growth and metastasis as well as LACTB's involvement in chemotherapeutic and immunotherapeutic responses; (2) sketches the structural basis for LACTB activity and function; and (3) highlights the relevant regulatory mechanisms to LACTB. The abnormal expression of LACTB has been associated with clinicopathological features of cancer tissues and outcomes of anticancer therapies. With the current pioneer researches on the tumor-suppressed function, structural basis, and regulatory mechanism of LACTB, the perspective hints at a great appeal of enzymic property, polymerization, mutation, and epigenetic and post-translational modifications in investigating LACTB's role in cancer pathogenesis. This perspective provides novel insights for LACTB as a metabolic regulator with potential to develop targeted cancer therapies or neoadjuvant therapeutic interventions.
Topics: Animals; Mammals; Membrane Proteins; Mitochondria; Mitochondrial Proteins; Neoplasms; beta-Lactamases
PubMed: 36078157
DOI: 10.3390/cells11172749 -
Clinical Microbiology and Infection :... Jan 2008Acquired resistance to penicillin-beta-lactamase inhibitor combinations in Escherichia coli is due to: (i) penicillinase hyperproduction due to the presence of the... (Review)
Review
Acquired resistance to penicillin-beta-lactamase inhibitor combinations in Escherichia coli is due to: (i) penicillinase hyperproduction due to the presence of the bla(TEM-1) gene in small multicopy plasmids or strong promoters; (ii) overproduction of constitutive AmpC cephalosporinase; and (iii) OXA-type and inhibitor-resistant TEM (IRT) beta-lactamases. IRT enzymes emerge via mutational events from TEM-1 or TEM-2 beta-lactamases that affect substrate affinity for beta-lactamase inhibitors. They are mainly isolated in urinary infections from community patients. Prevalence is variable, depending on geographical area, detection methods and potential selection pressure. These enzymes may evolve into complex mutants (CMT enzymes), which also confer resistance to extended-spectrum cephalosporins. CTX-M enzymes with the IRT phenotype have not been detected to date. New studies of IRT enzymes, including population structure, association with virulence traits and plasmid dispersion, are needed.
Topics: Amino Acid Substitution; Enzyme Inhibitors; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Humans; Urinary Tract Infections; beta-Lactam Resistance; beta-Lactamase Inhibitors; beta-Lactamases; beta-Lactams
PubMed: 18154528
DOI: 10.1111/j.1469-0691.2007.01849.x