1
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Penicillin Binding Proteins and β-Lactamases of Mycobacterium tuberculosis: Reexamination of the Historical Paradigm. mSphere 2022; 7:e0003922. [PMID: 35196121 PMCID: PMC8865919 DOI: 10.1128/msphere.00039-22] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Penicillin binding proteins (PBPs) have been extensively studied due to their importance to the physiology of bacterial cell wall peptidoglycan and as targets of the most widely used class of antibiotics, the β-lactams. The existing paradigm asserts that PBPs catalyze the final step of peptidoglycan biosynthesis, and β-lactams inhibit their activities. According to this paradigm, a distinct enzyme class, β-lactamases, exists to inactivate β-lactams. This paradigm has been the basis for how bacterial diseases are treated with β-lactams. We tested whether this historical view accurately reflects the relationship between β-lactams and the PBPs and the β-lactamase, BlaC, of Mycobacterium tuberculosis. BlaC was the major inactivator of the cephalosporin subclass of β-lactams. However, the PBPs PonA1 and PonA2 inactivated penicillins and carbapenems more effectively than BlaC. These findings demonstrate that select M. tuberculosis PBPs are effective at inactivating several β-lactams. Lesser-known PBPs, DacB, DacB1, DacB2, and Rv2864c, a putative PBP, were comparably more resistant to inhibition by all β-lactam subclasses. Additionally, Rv1730c exhibited low affinity to most β-lactams. Based on these findings, we conclude that in M. tuberculosis, BlaC is not the only source of inactivation of β-lactams. Therefore, the historical paradigm does not accurately describe the relationship between β-lactams and M. tuberculosis. IMPORTANCE M. tuberculosis, the causative agent of tuberculosis, kills more humans than any other bacterium. β-lactams are the most widely used class of antibiotics to treat bacterial infections. Unlike in the historical model that describes the relationship between β-lactams and M. tuberculosis, we find that M. tuberculosis penicillin binding proteins are able to inactivate select β-lactams with high efficiency.
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2
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Taylor DM, Anglin J, Hu L, Wang L, Sankaran B, Wang J, Matzuk MM, Prasad BV, Palzkill T. Unique Diacidic Fragments Inhibit the OXA-48 Carbapenemase and Enhance the Killing of Escherichia coli Producing OXA-48. ACS Infect Dis 2021; 7:3345-3354. [PMID: 34817169 PMCID: PMC9677231 DOI: 10.1021/acsinfecdis.1c00501] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Despite the advances in β-lactamase inhibitor development, limited options exist for the class D carbapenemase known as OXA-48. OXA-48 is one of the most prevalent carbapenemases in carbapenem-resistant Enterobacteriaceae infections and is not susceptible to most available β-lactamase inhibitors. Here, we screened various low-molecular-weight compounds (fragments) against OXA-48 to identify functional scaffolds for inhibitor development. Several biphenyl-, naphthalene-, fluorene-, anthraquinone-, and azobenzene-based compounds were found to inhibit OXA-48 with low micromolar potency despite their small size. Co-crystal structures of OXA-48 with several of these compounds revealed key interactions with the carboxylate-binding pocket, Arg214, and various hydrophobic residues of β-lactamase that can be exploited in future inhibitor development. A number of the low-micromolar-potency inhibitors, across different scaffolds, synergize with ampicillin to kill Escherichia coli expressing OXA-48, albeit at high concentrations of the respective inhibitors. Additionally, several compounds demonstrated micromolar potency toward the OXA-24 and OXA-58 class D carbapenemases that are prevalent in Acinetobacter baumannii. This work provides foundational information on a variety of chemical scaffolds that can guide the design of effective OXA-48 inhibitors that maintain efficacy as well as potency toward other major class D carbapenemases.
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Affiliation(s)
- Doris Mia Taylor
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Justin Anglin
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Liya Hu
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Lingfei Wang
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Advanced Light Source, Lawrence Berkeley National Laboratory, CA, 94720, USA
| | - Jin Wang
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Martin M. Matzuk
- Center for Drug Discovery, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pathology & Immunology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - B.V. Venkataram Prasad
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Timothy Palzkill
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, 77030, USA
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, 77030, USA
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3
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Aertker KMJ, Chan HTH, Lohans CT, Schofield CJ. Analysis of β-lactone formation by clinically observed carbapenemases informs on a novel antibiotic resistance mechanism. J Biol Chem 2020; 295:16604-16613. [PMID: 32963107 PMCID: PMC7864059 DOI: 10.1074/jbc.ra120.014607] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 09/07/2020] [Indexed: 01/18/2023] Open
Abstract
An important mechanism of resistance to β-lactam antibiotics is via their β-lactamase-catalyzed hydrolysis. Recent work has shown that, in addition to the established hydrolysis products, the reaction of the class D nucleophilic serine β-lactamases (SBLs) with carbapenems also produces β-lactones. We report studies on the factors determining β-lactone formation by class D SBLs. We show that variations in hydrophobic residues at the active site of class D SBLs (i.e. Trp105, Val120, and Leu158, using OXA-48 numbering) impact on the relative levels of β-lactones and hydrolysis products formed. Some variants, i.e. the OXA-48 V120L and OXA-23 V128L variants, catalyze increased β-lactone formation compared with the WT enzymes. The results of kinetic and product studies reveal that variations of residues other than those directly involved in catalysis, including those arising from clinically observed mutations, can alter the reaction outcome of class D SBL catalysis. NMR studies show that some class D SBL variants catalyze formation of β-lactones from all clinically relevant carbapenems regardless of the presence or absence of a 1β-methyl substituent. Analysis of reported crystal structures for carbapenem-derived acyl-enzyme complexes reveals preferred conformations for hydrolysis and β-lactone formation. The observation of increased β-lactone formation by class D SBL variants, including the clinically observed carbapenemase OXA-48 V120L, supports the proposal that class D SBL-catalyzed rearrangement of β-lactams to β-lactones is important as a resistance mechanism.
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Affiliation(s)
| | - H T Henry Chan
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom
| | - Christopher T Lohans
- Chemistry Research Laboratory, University of Oxford, Oxford, United Kingdom; Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.
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4
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Ding Y, Li Z, Xu C, Qin W, Wu Q, Wang X, Cheng X, Li L, Huang W. Fluorogenic Probes/Inhibitors of β-Lactamase and their Applications in Drug-Resistant Bacteria. Angew Chem Int Ed Engl 2020; 60:24-40. [PMID: 32592283 DOI: 10.1002/anie.202006635] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Indexed: 01/08/2023]
Abstract
β-Lactam antibiotics are generally perceived as one of the greatest inventions of the 20th century, and these small molecular compounds have saved millions of lives. However, upon clinical application of antibiotics, the β-lactamase secreted by pathogenic bacteria can lead to the gradual development of drug resistance. β-Lactamase is a hydrolase that can efficiently hydrolyze and destroy β-lactam antibiotics. It develops and spreads rapidly in pathogens, and the drug-resistant bacteria pose a severe threat to human health and development. As a result, detecting and inhibiting the activities of β-lactamase are of great value for the rational use of antibiotics and the treatment of infectious diseases. At present, many specific detection methods and inhibitors of β-lactamase have been developed and applied in clinical practice. In this Minireview, we describe the resistance mechanism of bacteria producing β-lactamase and further summarize the fluorogenic probes, inhibitors of β-lactamase, and their applications in the treatment of infectious diseases. It may be valuable to design fluorogenic probes with improved selectivity, sensitivity, and effectiveness to further identify the inhibitors for β-lactamases and eventually overcome bacterial resistance.
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Affiliation(s)
- Yang Ding
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Zheng Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Chenchen Xu
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Wenjing Qin
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Qiong Wu
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Xuchun Wang
- College of Chemistry and Material Engineering, University of Science and Technology of Anhui, Bengbu, 233000, P. R. China
| | - Xiamin Cheng
- Institute of Advanced Synthesis, School of Chemistry and Molecular Engineering, Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Lin Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China
| | - Wei Huang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM), Nanjing Tech University (NanjingTech), Nanjing, 211816, P. R. China.,Frontiers Science Center for Flexible Electronics (FSCFE), Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME), Northwestern Polytechnical University (NPU), Xi'an, 710072, P. R. China
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5
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Ding Y, Li Z, Xu C, Qin W, Wu Q, Wang X, Cheng X, Li L, Huang W. Fluorogenic Probes/Inhibitors of β‐Lactamase and their Applications in Drug‐Resistant Bacteria. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202006635] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Yang Ding
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Zheng Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Chenchen Xu
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Wenjing Qin
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Qiong Wu
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Xuchun Wang
- College of Chemistry and Material Engineering University of Science and Technology of Anhui Bengbu 233000 P. R. China
| | - Xiamin Cheng
- Institute of Advanced Synthesis School of Chemistry and Molecular Engineering Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Lin Li
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
| | - Wei Huang
- Key Laboratory of Flexible Electronics (KLOFE) & Institute of Advanced Materials (IAM) Nanjing Tech University (NanjingTech) Nanjing 211816 P. R. China
- Frontiers Science Center for Flexible Electronics (FSCFE) Shaanxi Institute of Flexible Electronics (SIFE) & Shaanxi Institute of Biomedical Materials and Engineering (SIBME) Northwestern Polytechnical University (NPU) Xi'an 710072 P. R. China
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Structural Analysis of The OXA-48 Carbapenemase Bound to A "Poor" Carbapenem Substrate, Doripenem. Antibiotics (Basel) 2019; 8:antibiotics8030145. [PMID: 31514291 PMCID: PMC6783824 DOI: 10.3390/antibiotics8030145] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 08/30/2019] [Accepted: 09/04/2019] [Indexed: 12/11/2022] Open
Abstract
Carbapenem-resistant Enterobacteriaceae are a significant threat to public health, and a major resistance determinant that promotes this phenotype is the production of the OXA-48 carbapenemase. The activity of OXA-48 towards carbapenems is a puzzling phenotype as its hydrolytic activity against doripenem is non-detectable. To probe the mechanistic basis for this observation, we determined the 1.5 Å resolution crystal structure of the deacylation deficient K73A variant of OXA-48 in complex with doripenem. Doripenem is observed in the Δ1R and Δ1S tautomeric states covalently attached to the catalytic S70 residue. Likely due to positioning of residue Y211, the carboxylate moiety of doripenem is making fewer hydrogen bonding/salt-bridge interactions with R250 compared to previously determined carbapenem OXA structures. Moreover, the hydroxyethyl side chain of doripenem is making van der Waals interactions with a key V120 residue, which likely affects the deacylation rate of doripenem. We hypothesize that positions V120 and Y211 play important roles in the carbapenemase profile of OXA-48. Herein, we provide insights for the further development of the carbapenem class of antibiotics that could render them less effective to hydrolysis by or even inhibit OXA carbapenemases.
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7
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van Groesen E, Lohans CT, Brem J, Aertker KMJ, Claridge TDW, Schofield CJ. 19 F NMR Monitoring of Reversible Protein Post-Translational Modifications: Class D β-Lactamase Carbamylation and Inhibition. Chemistry 2019; 25:11837-11841. [PMID: 31310409 PMCID: PMC6771976 DOI: 10.1002/chem.201902529] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/11/2019] [Indexed: 11/05/2022]
Abstract
Bacterial production of β‐lactamases with carbapenemase activity is a global health threat. The active sites of class D carbapenemases such as OXA‐48, which is of major clinical importance, uniquely contain a carbamylated lysine residue which is essential for catalysis. Although there is significant interest in characterizing this post‐translational modification, and it is a promising inhibition target, protein carbamylation is challenging to monitor in solution. We report the use of 19F NMR spectroscopy to monitor the carbamylation state of 19F‐labelled OXA‐48. This method was used to investigate the interactions of OXA‐48 with clinically used serine β‐lactamase inhibitors, including avibactam and vaborbactam. Crystallographic studies on 19F‐labelled OXA‐48 provide a structural rationale for the sensitivity of the 19F label to active site interactions. The overall results demonstrate the use of 19F NMR to monitor reversible covalent post‐translational modifications.
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Affiliation(s)
- Emma van Groesen
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
| | - Christopher T Lohans
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK.,Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON, K7L 3N6, Canada
| | - Jürgen Brem
- Department of Chemistry, University of Oxford, Oxford, OX1 3TA, UK
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8
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Fluorescent Antibiotics: New Research Tools to Fight Antibiotic Resistance. Trends Biotechnol 2018; 36:523-536. [PMID: 29478675 DOI: 10.1016/j.tibtech.2018.01.004] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Revised: 01/10/2018] [Accepted: 01/11/2018] [Indexed: 01/02/2023]
Abstract
Better understanding how multidrug-resistant (MDR) bacteria can evade current and novel antibiotics requires a better understanding of the chemical biology of antibiotic action. This necessitates using new tools and techniques to advance our knowledge of bacterial responses to antibiotics, ideally in live cells in real time, to selectively investigate bacterial growth, division, metabolism, and resistance in response to antibiotic challenge. In this review, we discuss the preparation and biological evaluation of fluorescent antibiotics, focussing on how these reporters and assay methods can help elucidate resistance mechanisms. We also examine the potential utility of such probes for real-time in vivo diagnosis of infections.
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9
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Clinical Variants of the Native Class D β-Lactamase of Acinetobacter baumannii Pose an Emerging Threat through Increased Hydrolytic Activity against Carbapenems. Antimicrob Agents Chemother 2016; 60:6155-64. [PMID: 27480863 DOI: 10.1128/aac.01277-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 07/26/2016] [Indexed: 11/20/2022] Open
Abstract
The threat posed by the chromosomally encoded class D β-lactamase of Acinetobacter baumannii (OXA-51/66) has been unclear, in part because of its relatively low affinity and turnover rate for carbapenems. Several hundred clinical variants of OXA-51/66 have been reported, many with substitutions of active-site residues. We determined the kinetic properties of OXA-66 and five clinical variants with respect to a wide variety of β-lactam substrates. The five variants displayed enhanced activity against carbapenems and in some cases against penicillins, late-generation cephalosporins, and the monobactam aztreonam. Molecular dynamics simulations show that in OXA-66, P130 inhibits the side-chain rotation of I129 and thereby prevents doripenem binding because of steric clash. A single amino acid substitution at this position (P130Q) in the variant OXA-109 greatly enhances the mobility of both I129 and a key active-site tryptophan (W222), thereby facilitating carbapenem binding. This expansion of substrate specificity represents a very worrisome development for the efficacy of β-lactams against this troublesome pathogen.
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10
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Shapiro AB. Investigation of β-lactam antibacterial drugs, β-lactamases, and penicillin-binding proteins with fluorescence polarization and anisotropy: a review. Methods Appl Fluoresc 2016; 4:024002. [DOI: 10.1088/2050-6120/4/2/024002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Saino H, Sugiyabu T, Ueno G, Yamamoto M, Ishii Y, Miyano M. Crystal Structure of OXA-58 with the Substrate-Binding Cleft in a Closed State: Insights into the Mobility and Stability of the OXA-58 Structure. PLoS One 2015; 10:e0145869. [PMID: 26701320 PMCID: PMC4689445 DOI: 10.1371/journal.pone.0145869] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
OXA-58 is a class D β-lactamase from the multi-drug resistant Acinetobacter baumannii. We determined the crystal structure of OXA-58 in a novel crystal, and revealed the structure of the substrate-binding cleft in a closed state, distinct from a previously reported OXA-58 crystal structure with the binding cleft in an open state. In the closed state, the movement of three loops (α3-α4, β6-β7, and β8-α10) forms an arch-like architecture over the binding cleft through interaction between the Phe113 residues of α3-α4 and Met225 of β6-β7. This structure suggests the involvement of these flexible loops in OXA-58 substrate binding. In contrast to the mobile loops, the Ω-loop appeared static, including the conserved loop residues and their hydrogen bonds; the pivotal residue Trp169 within the Ω-loop, ζ-carbamic acid of the modified base catalyst residue Lys86, and nucleophilic residue Ser83. The stability of OXA-58 was enhanced concomitant with an increase in the hydrolytic activity catalyzed by NaHCO3-dependent ζ-carbamic acid formation, with an EC50 of 0.34 mM. The W169A mutant enzyme was significantly thermally unstable even in the presence of 100 mM NaHCO3, whereas the S83A mutant was stabilized with NaHCO3-dependent activation. The ζ-carbamic acid was shown to increase not only OXA-58 hydrolytic activity but also OXA-58 stability through the formation of a hydrogen bond network connected to the Ω-loop with Ser83 and Trp169. Thus, the static Ω-loop is important for OXA-58 stability, whereas the mobile loops of the substrate-binding cleft form the basis for accommodation of the various substituents of β-lactam backbone.
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Affiliation(s)
- Hiromichi Saino
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara-shi, Kanagawa, Japan
- * E-mail:
| | - Tomohiro Sugiyabu
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara-shi, Kanagawa, Japan
| | - Go Ueno
- Advanced Photon Technology Division, RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
| | - Masaki Yamamoto
- Advanced Photon Technology Division, RIKEN SPring-8 Center, Sayo-gun, Hyogo, Japan
| | - Yoshikazu Ishii
- Department of Microbiology and Infectious Diseases, Faculty of Medicine, Toho University, Ota-ku, Tokyo, Japan
| | - Masashi Miyano
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University, Sagamihara-shi, Kanagawa, Japan
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12
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June CM, Vaughan RM, Ulberg LS, Bonomo RA, Witucki LA, Leonard DA. A fluorescent carbapenem for structure function studies of penicillin-binding proteins, β-lactamases, and β-lactam sensors. Anal Biochem 2014; 463:70-4. [PMID: 25058926 DOI: 10.1016/j.ab.2014.07.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 07/12/2014] [Indexed: 11/29/2022]
Abstract
By reacting fluorescein isothiocyanate with meropenem, we have prepared a carbapenem-based fluorescent β-lactam. Fluorescein-meropenem binds both penicillin-binding proteins and β-lactam sensors and undergoes a typical acylation reaction in the active site of these proteins. The probe binds the class D carbapenemase OXA-24/40 with close to the same affinity as meropenem and undergoes a complete catalytic hydrolysis reaction. The visible light excitation and strong emission of fluorescein render this molecule a useful structure-function probe through its application in sodium dodecyl sulfate-polyacrylamide gel electrophoresis assays as well as solution-based kinetic anisotropy assays. Its classification as a carbapenem β-lactam and the position of its fluorescent modification render it a useful complement to other fluorescent β-lactams, most notably Bocillin FL. In this study, we show the utility of fluorescein-meropenem by using it to detect mutants of OXA-24/40 that arrest at the acyl-intermediate state with carbapenem substrates but maintain catalytic competency with penicillin substrates.
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Affiliation(s)
- Cynthia M June
- Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA
| | - Robert M Vaughan
- Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA
| | - Lucas S Ulberg
- Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA
| | - Robert A Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, and Department of Pharmacology, Molecular Biology, and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH 44106, USA
| | - Laurie A Witucki
- Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA
| | - David A Leonard
- Department of Chemistry, Grand Valley State University, Allendale, MI 49401, USA.
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Che T, Bethel CR, Pusztai-Carey M, Bonomo RA, Carey PR. The different inhibition mechanisms of OXA-1 and OXA-24 β-lactamases are determined by the stability of active site carboxylated lysine. J Biol Chem 2014; 289:6152-64. [PMID: 24443569 DOI: 10.1074/jbc.m113.533562] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
The catalytic efficiency of class D β-lactamases depends critically on an unusual carboxylated lysine as the general base residue for both the acylation and deacylation steps of the enzyme. Microbiological and biochemical studies on the class D β-lactamases OXA-1 and OXA-24 showed that the two enzymes behave differently when reacting with two 6-methylidene penems (penem 1 and penem 3): the penems are good inhibitors of OXA-1 but act more like substrates for OXA-24. UV difference and Raman spectroscopy revealed that the respective reaction mechanisms are different. The penems form an unusual intermediate, a 1,4-thiazepine derivative in OXA-1, and undergo deacylation followed by the decarboxylation of Lys-70, rendering OXA-1 inactive. This inactivation could not be reversed by the addition of 100 mM NaHCO3. In OXA-24, under mild conditions (enzyme:inhibitor = 1:4), only hydrolyzed products were detected, and the enzyme remained active. However, under harsh conditions (enzyme:inhibitor = 1:2000), OXA-24 was inhibited via decarboxylation of Lys-84; however, the enzyme could be reactivated by the addition of 100 mM NaHCO3. We conclude that OXA-24 not only decarboxylates with difficulty but also recarboxylates with ease; in contrast, OXA-1 decarboxylates easily but recarboxylates with difficulty. Structural analysis of the active site indicates that a crystallographic water molecule may play an important role in carboxylation in OXA-24 (an analogous water molecule is not found in OXA-1), supporting the suggestion that a water molecule in the active site of OXA-24 can lower the energy barrier for carboxylation significantly.
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Affiliation(s)
- Tao Che
- From the Departments of Biochemistry
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14
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Jimenez-Morales D, Adamian L, Shi D, Liang J. Lysine carboxylation: unveiling a spontaneous post-translational modification. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:48-57. [PMID: 24419378 PMCID: PMC3919261 DOI: 10.1107/s139900471302364x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Accepted: 08/22/2013] [Indexed: 11/10/2022]
Abstract
The carboxylation of lysine residues is a post-translational modification (PTM) that plays a critical role in the catalytic mechanisms of several important enzymes. It occurs spontaneously under certain physicochemical conditions, but is difficult to detect experimentally. Its full impact is unknown. In this work, the signature microenvironment of lysine-carboxylation sites has been characterized. In addition, a computational method called Predictor of Lysine Carboxylation (PreLysCar) for the detection of lysine carboxylation in proteins with available three-dimensional structures has been developed. The likely prevalence of lysine carboxylation in the proteome was assessed through large-scale computations. The results suggest that about 1.3% of large proteins may contain a carboxylated lysine residue. This unexpected prevalence of lysine carboxylation implies an enrichment of reactions in which it may play functional roles. The results also suggest that by switching enzymes on and off under appropriate physicochemical conditions spontaneous PTMs may serve as an important and widely used efficient biological machinery for regulation.
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Affiliation(s)
- David Jimenez-Morales
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Room 218, Chicago, IL 60607, USA
| | - Larisa Adamian
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Room 218, Chicago, IL 60607, USA
| | - Dashuang Shi
- Children’s National Medical Center, Center for Genetic Medicine Research, 111 Michigan Avenue NW, Washington, DC 20010-2970, USA
| | - Jie Liang
- Department of Bioengineering, University of Illinois at Chicago, 851 South Morgan Street, Room 218, Chicago, IL 60607, USA
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15
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Leonard DA, Bonomo RA, Powers RA. Class D β-lactamases: a reappraisal after five decades. Acc Chem Res 2013; 46:2407-15. [PMID: 23902256 DOI: 10.1021/ar300327a] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Despite 70 years of clinical use, β-lactam antibiotics still remain at the forefront of antimicrobial chemotherapy. The major challenge to these life-saving therapeutics is the presence of bacterial enzymes (i.e., β-lactamases) that can hydrolyze the β-lactam bond and inactivate the antibiotic. These enzymes can be grouped into four classes (A-D). Among the most genetically diverse are the class D β-lactamases. In this class are β-lactamases that can inactivate the entire spectrum of β-lactam antibiotics (penicillins, cephalosporins, and carbapenems). Class D β-lactamases are mostly found in Gram-negative bacteria such as Pseudomonas aeruginosa , Escherichia coli , Proteus mirabilis , and Acinetobacter baumannii . The active-sites of class D β-lactamases contain an unusual N-carboxylated lysine post-translational modification. A strongly hydrophobic active-site helps create the conditions that allow the lysine to combine with CO2, and the resulting carbamate is stabilized by a number of hydrogen bonds. The carboxy-lysine plays a symmetric role in the reaction, serving as a general base to activate the serine nucleophile in the acylation reaction, and the deacylating water in the second step. There are more than 250 class D β-lactamases described, and the full set of variants shows remarkable diversity with regard to substrate binding and turnover. Narrow-spectrum variants are most effective against the earliest generation penicillins and cephalosporins such as ampicillin and cephalothin. Extended-spectrum variants (also known as extended-spectrum β-lactamases, ESBLs) pose a more dangerous clinical threat as they possess a small number of substitutions that allow them to bind and hydrolyze later generation cephalosporins that contain bulkier side-chain constituents (e.g., cefotaxime, ceftazidime, and cefepime). Mutations that permit this versatility seem to cluster in the area surrounding an active-site tryptophan resulting in a widened active-site to accommodate the oxyimino side-chains of these cephalosporins. More concerning are the class D β-lactamases that hydrolyze clinically important carbapenem β-lactam drugs (e.g., imipenem). Whereas carbapenems irreversibly acylate and inhibit narrow-spectrum β-lactamases, class D carbapenemases are able to recruit and activate a deacylating water. The rotational orientation of the C6 hydroxyethyl group found on all carbapenem antibiotics likely plays a role in whether the deacylating water is effective or not. Inhibition of class D β-lactamases is a current challenge. Commercially available inhibitors that are active against other classes of β-lactamases are ineffective against class D enzymes. On the horizon are several compounds, consisting of both β-lactam derivatives and non-β-lactams, that have the potential of providing novel leads to design new mechanism-based inactivators that are effective against the class D enzymes. Several act synergistically when given in combination with a β-lactam antibiotic, and others show a unique mechanism of inhibition that is distinct from the traditional β-lactamase inhibitors. These studies will bolster structure-based inhibitor design efforts to facilitate the optimization and development of these compounds as class D inactivators.
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Affiliation(s)
- David A. Leonard
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, United States
| | - Robert A. Bonomo
- Research Service, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, and Department of Pharmacology, Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, United States
| | - Rachel A. Powers
- Department of Chemistry, Grand Valley State University, Allendale, Michigan 49401, United States
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16
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Cain JA, Solis N, Cordwell SJ. Beyond gene expression: the impact of protein post-translational modifications in bacteria. J Proteomics 2013; 97:265-86. [PMID: 23994099 DOI: 10.1016/j.jprot.2013.08.012] [Citation(s) in RCA: 136] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 07/08/2013] [Accepted: 08/10/2013] [Indexed: 12/12/2022]
Abstract
The post-translational modification (PTM) of proteins plays a critical role in the regulation of a broad range of cellular processes in eukaryotes. Yet their role in governing similar systems in the conventionally presumed 'simpler' forms of life has been largely neglected and, until recently, was thought to occur only rarely, with some modifications assumed to be limited to higher organisms alone. Recent developments in mass spectrometry-based proteomics have provided an unparalleled power to enrich, identify and quantify peptides with PTMs. Additional modifications to biological molecules such as lipids and carbohydrates that are essential for bacterial pathophysiology have only recently been detected on proteins. Here we review bacterial protein PTMs, focusing on phosphorylation, acetylation, proteolytic degradation, methylation and lipidation and the roles they play in bacterial adaptation - thus highlighting the importance of proteomic techniques in a field that is only just in its infancy. This article is part of a Special Issue entitled: Trends in Microbial Proteomics.
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Affiliation(s)
- Joel A Cain
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Nestor Solis
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia
| | - Stuart J Cordwell
- School of Molecular Bioscience, School of Medical Sciences, The University of Sydney, 2006, Australia; Discipline of Pathology, School of Medical Sciences, The University of Sydney, 2006, Australia.
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17
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Shapiro AB, Gu RF, Gao N, Livchak S, Thresher J. Continuous fluorescence anisotropy-based assay of BOCILLIN FL penicillin reaction with penicillin binding protein 3. Anal Biochem 2013; 439:37-43. [PMID: 23603065 DOI: 10.1016/j.ab.2013.04.009] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2013] [Revised: 03/12/2013] [Accepted: 04/01/2013] [Indexed: 10/27/2022]
Abstract
We report a simple, rapid, and reproducible fluorescence anisotropy-based method for measuring rate constants for acylation and deacylation of soluble penicillin binding protein (PBP) constructs by compounds in microtiter plates by means of competition with time-dependent acylation by BOCILLIN FL. The method is demonstrated by measuring the acylation rate constants of the PBP3 periplasmic domains from Pseudomonas aeruginosa and Acinetobacter baumannii by BOCILLIN FL, aztreonam, meropenem, and ceftazidime. The new method requires very little protein and can be completed in approximately 1h per compound. A set of BOCILLIN FL acylation progress curves collected over a range of competitor concentrations is fit globally to a kinetic model by numerical integration. First-order deacylation rate constants could also be measured, as demonstrated with a catalytically impaired mutant OXA-10 β-lactamase.
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Affiliation(s)
- Adam B Shapiro
- Bioscience Department, Infection Innovative Medicines, AstraZeneca R&D Boston, Waltham, MA 02451, USA.
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