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Judge A, Hu L, Sankaran B, Van Riper J, Venkataram Prasad BV, Palzkill T. Mapping the determinants of catalysis and substrate specificity of the antibiotic resistance enzyme CTX-M β-lactamase. Commun Biol 2023; 6:35. [PMID: 36635385 PMCID: PMC9837174 DOI: 10.1038/s42003-023-04422-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 01/04/2023] [Indexed: 01/14/2023] Open
Abstract
CTX-M β-lactamases are prevalent antibiotic resistance enzymes and are notable for their ability to rapidly hydrolyze the extended-spectrum cephalosporin, cefotaxime. We hypothesized that the active site sequence requirements of CTX-M-mediated hydrolysis differ between classes of β-lactam antibiotics. Accordingly, we use codon randomization, antibiotic selection, and deep sequencing to determine the CTX-M active-site residues required for hydrolysis of cefotaxime and the penicillin, ampicillin. The study reveals positions required for hydrolysis of all β-lactams, as well as residues controlling substrate specificity. Further, CTX-M enzymes poorly hydrolyze the extended-spectrum cephalosporin, ceftazidime. We further show that the sequence requirements for ceftazidime hydrolysis follow those of cefotaxime, with the exception that key active-site omega loop residues are not required, and may be detrimental, for ceftazidime hydrolysis. These results provide insights into cephalosporin hydrolysis and demonstrate that changes to the active-site omega loop are likely required for the evolution of CTX-M-mediated ceftazidime resistance.
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Affiliation(s)
- Allison Judge
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Liya Hu
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Banumathi Sankaran
- Department of Molecular Biophysics and Integrated Bioimaging, Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
| | - Justin Van Riper
- Graduate Program in Chemical, Physical, and Structural Biology, Baylor College of Medicine, Houston, TX, USA
| | - B V Venkataram Prasad
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA
| | - Timothy Palzkill
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX, USA.
- Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, TX, USA.
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2
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Avery C, Baker L, Jacobs DJ. Functional Dynamics of Substrate Recognition in TEM Beta-Lactamase. ENTROPY 2022; 24:e24050729. [PMID: 35626612 PMCID: PMC9140794 DOI: 10.3390/e24050729] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 05/16/2022] [Accepted: 05/18/2022] [Indexed: 02/01/2023]
Abstract
The beta-lactamase enzyme provides effective resistance to beta-lactam antibiotics due to substrate recognition controlled by point mutations. Recently, extended-spectrum and inhibitor-resistant mutants have become a global health problem. Here, the functional dynamics that control substrate recognition in TEM beta-lactamase are investigated using all-atom molecular dynamics simulations. Comparisons are made between wild-type TEM-1 and TEM-2 and the extended-spectrum mutants TEM-10 and TEM-52, both in apo form and in complex with four different antibiotics (ampicillin, amoxicillin, cefotaxime and ceftazidime). Dynamic allostery is predicted based on a quasi-harmonic normal mode analysis using a perturbation scan. An allosteric mechanism known to inhibit enzymatic function in TEM beta-lactamase is identified, along with other allosteric binding targets. Mechanisms for substrate recognition are elucidated using multivariate comparative analysis of molecular dynamics trajectories to identify changes in dynamics resulting from point mutations and ligand binding, and the conserved dynamics, which are functionally important, are extracted as well. The results suggest that the H10-H11 loop (residues 214-221) is a secondary anchor for larger extended spectrum ligands, while the H9-H10 loop (residues 194-202) is distal from the active site and stabilizes the protein against structural changes. These secondary non-catalytically-active loops offer attractive targets for novel noncompetitive inhibitors of TEM beta-lactamase.
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Affiliation(s)
- Chris Avery
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (C.A.); (L.B.)
| | - Lonnie Baker
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (C.A.); (L.B.)
| | - Donald J. Jacobs
- Department of Physics and Optical Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA
- Correspondence:
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3
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Elings W, Chikunova A, van Zanten DB, Drenth R, Ahmad MUD, Blok AJ, Timmer M, Perrakis A, Ubbink M. Two β-Lactamase Variants with Reduced Clavulanic Acid Inhibition Display Different Millisecond Dynamics. Antimicrob Agents Chemother 2021; 65:e0262820. [PMID: 34031049 PMCID: PMC8284444 DOI: 10.1128/aac.02628-20] [Citation(s) in RCA: 6] [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: 12/20/2020] [Accepted: 05/07/2021] [Indexed: 11/20/2022] Open
Abstract
The β-lactamase of Mycobacterium tuberculosis, BlaC, is susceptible to inhibition by clavulanic acid. The ability of this enzyme to escape inhibition through mutation was probed using error-prone PCR combined with functional screening in Escherichia coli. The variant that was found to confer the most inhibitor resistance, K234R, as well as variant G132N that was found previously were characterized using X-ray crystallography and nuclear magnetic resonance (NMR) relaxation experiments to probe structural and dynamic properties. The G132N mutant exists in solution in two almost equally populated conformations that exchange with a rate of ca. 88 s-1. The conformational change affects a broad region of the enzyme. The crystal structure reveals that the Asn132 side chain forces the peptide bond between Ser104 and Ile105 in a cis-conformation. The crystal structure suggests multiple conformations for several side chains (e.g., Ser104 and Ser130) and a short loop (positions 214 to 216). In the K234R mutant, the active-site dynamics are significantly diminished with respect to the wild-type enzyme. These results show that multiple evolutionary routes are available to increase inhibitor resistance in BlaC and that active-site dynamics on the millisecond time scale are not required for catalytic function.
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Affiliation(s)
- Wouter Elings
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | | | | | - Ralphe Drenth
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Misbha Ud Din Ahmad
- Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
| | - Anneloes J. Blok
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Monika Timmer
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
| | - Anastassis Perrakis
- Division of Biochemistry, the Netherlands Cancer Institute, Amsterdam, The Netherlands
- Oncode Institute, Amsterdam, The Netherlands
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Leiden University, Leiden, The Netherlands
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4
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Wei WM, Xu YL, Zheng RH, Zhao T, Fang W, Qin YD. Theoretical Study on the Mechanism of the Acylate Reaction of β-Lactamase. ACS OMEGA 2021; 6:12598-12604. [PMID: 34056410 PMCID: PMC8154126 DOI: 10.1021/acsomega.1c00592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/26/2021] [Indexed: 05/25/2023]
Abstract
Using density functional theory and a cluster approach, we study the reaction potential surface and compute Gibbs free energies for the acylate reaction of β-lactamase with penicillin G, where the solvent effect is important and taken into consideration. Two reaction paths are investigated: one is a multi-step process with a rate-limit energy barrier of 19.1 kcal/mol, which is relatively small, and the reaction can easily occur; the other is a one-step process with a barrier of 45.0 kcal/mol, which is large and thus makes the reaction hard to occur. The reason why the two paths have different barriers is explained.
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Affiliation(s)
- Wen-Mei Wei
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Yan-Li Xu
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Ren-Hui Zheng
- Beijing
National Laboratory for Molecular Sciences, State Key Laboratory for
Structural Chemistry of Unstable and Stable Species, Institute of
Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, P. R. China
| | - Tingting Zhao
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Weijun Fang
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
| | - Yi-De Qin
- School
of Basic Medical Sciences, Anhui Medical
University, Hefei, Anhui 230032, P.
R. China
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5
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The Role of Rigid Residues in Modulating TEM-1 β-Lactamase Function and Thermostability. Int J Mol Sci 2021; 22:ijms22062895. [PMID: 33809335 PMCID: PMC7999226 DOI: 10.3390/ijms22062895] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Revised: 03/09/2021] [Accepted: 03/10/2021] [Indexed: 01/18/2023] Open
Abstract
The relationship between protein motions (i.e., dynamics) and enzymatic function has begun to be explored in β-lactamases as a way to advance our understanding of these proteins. In a recent study, we analyzed the dynamic profiles of TEM-1 (a ubiquitous class A β-lactamase) and several ancestrally reconstructed homologues. A chief finding of this work was that rigid residues that were allosterically coupled to the active site appeared to have profound effects on enzyme function, even when separated from the active site by many angstroms. In the present work, our aim was to further explore the implications of protein dynamics on β-lactamase function by altering the dynamic profile of TEM-1 using computational protein design methods. The Rosetta software suite was used to mutate amino acids surrounding either rigid residues that are highly coupled to the active site or to flexible residues with no apparent communication with the active site. Experimental characterization of ten designed proteins indicated that alteration of residues surrounding rigid, highly coupled residues, substantially affected both enzymatic activity and stability; in contrast, native-like activities and stabilities were maintained when flexible, uncoupled residues, were targeted. Our results provide additional insight into the structure-function relationship present in the TEM family of β-lactamases. Furthermore, the integration of computational protein design methods with analyses of protein dynamics represents a general approach that could be used to extend our understanding of the relationship between dynamics and function in other enzyme classes.
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6
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Alejaldre L, Lemay-St-Denis C, Perez Lopez C, Sancho Jodar F, Guallar V, Pelletier JN. Known Evolutionary Paths Are Accessible to Engineered ß-Lactamases Having Altered Protein Motions at the Timescale of Catalytic Turnover. Front Mol Biosci 2020; 7:599298. [PMID: 33330628 PMCID: PMC7716773 DOI: 10.3389/fmolb.2020.599298] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 10/23/2020] [Indexed: 11/26/2022] Open
Abstract
The evolution of new protein functions is dependent upon inherent biophysical features of proteins. Whereas, it has been shown that changes in protein dynamics can occur in the course of directed molecular evolution trajectories and contribute to new function, it is not known whether varying protein dynamics modify the course of evolution. We investigate this question using three related ß-lactamases displaying dynamics that differ broadly at the slow timescale that corresponds to catalytic turnover yet have similar fast dynamics, thermal stability, catalytic, and substrate recognition profiles. Introduction of substitutions E104K and G238S, that are known to have a synergistic effect on function in the parent ß-lactamase, showed similar increases in catalytic efficiency toward cefotaxime in the related ß-lactamases. Molecular simulations using Protein Energy Landscape Exploration reveal that this results from stabilizing the catalytically-productive conformations, demonstrating the dominance of the synergistic effect of the E014K and G238S substitutions in vitro in contexts that vary in terms of sequence and dynamics. Furthermore, three rounds of directed molecular evolution demonstrated that known cefotaximase-enhancing mutations were accessible regardless of the differences in dynamics. Interestingly, specific sequence differences between the related ß-lactamases were shown to have a higher effect in evolutionary outcomes than did differences in dynamics. Overall, these ß-lactamase models show tolerance to protein dynamics at the timescale of catalytic turnover in the evolution of a new function.
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Affiliation(s)
- Lorea Alejaldre
- Biochemistry Department, Université de Montréal, Montréal, QC, Canada.,PROTEO, The Québec Network for Research on Protein, Function, Engineering and Applications, Quebec City, QC, Canada.,CGCC, Center in Green Chemistry and Catalysis, Montréal, QC, Canada
| | - Claudèle Lemay-St-Denis
- Biochemistry Department, Université de Montréal, Montréal, QC, Canada.,PROTEO, The Québec Network for Research on Protein, Function, Engineering and Applications, Quebec City, QC, Canada.,CGCC, Center in Green Chemistry and Catalysis, Montréal, QC, Canada
| | | | | | - Victor Guallar
- Barcelona Supercomputing Center, Barcelona, Spain.,ICREA: Institució Catalana de Recerca i Estudis Avancats, Barcelona, Spain
| | - Joelle N Pelletier
- Biochemistry Department, Université de Montréal, Montréal, QC, Canada.,PROTEO, The Québec Network for Research on Protein, Function, Engineering and Applications, Quebec City, QC, Canada.,CGCC, Center in Green Chemistry and Catalysis, Montréal, QC, Canada.,Chemistry Department, Université de Montréal, Montréal, QC, Canada
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7
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Boulton S, Van K, VanSchouwen B, Augustine J, Akimoto M, Melacini G. Allosteric Mechanisms of Nonadditive Substituent Contributions to Protein-Ligand Binding. Biophys J 2020; 119:1135-1146. [PMID: 32882185 DOI: 10.1016/j.bpj.2020.07.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 02/07/2023] Open
Abstract
Quantifying chemical substituent contributions to ligand-binding free energies is challenging due to nonadditive effects. Protein allostery is a frequent cause of nonadditivity, but the underlying allosteric mechanisms often remain elusive. Here, we propose a general NMR-based approach to elucidate such mechanisms and we apply it to the HCN4 ion channel, whose cAMP-binding domain is an archetypal conformational switch. Using NMR, we show that nonadditivity arises not only from concerted conformational transitions, but also from conformer-specific effects, such as steric frustration. Our results explain how affinity-reducing functional groups may lead to affinity gains if combined. Surprisingly, our approach also reveals that nonadditivity depends markedly on the receptor conformation. It is negligible for the inhibited state but highly significant for the active state, opening new opportunities to tune potency and agonism of allosteric effectors.
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Affiliation(s)
- Stephen Boulton
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Katherine Van
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Jerry Augustine
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada.
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8
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Mechanism of proton transfer in class A β-lactamase catalysis and inhibition by avibactam. Proc Natl Acad Sci U S A 2020; 117:5818-5825. [PMID: 32123084 DOI: 10.1073/pnas.1922203117] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Gram-negative bacteria expressing class A β-lactamases pose a serious health threat due to their ability to inactivate all β-lactam antibiotics. The acyl-enzyme intermediate is a central milestone in the hydrolysis reaction catalyzed by these enzymes. However, the protonation states of the catalytic residues in this complex have never been fully analyzed experimentally due to inherent difficulties. To help unravel the ambiguity surrounding class A β-lactamase catalysis, we have used ultrahigh-resolution X-ray crystallography and the recently approved β-lactamase inhibitor avibactam to trap the acyl-enzyme complex of class A β-lactamase CTX-M-14 at varying pHs. A 0.83-Å-resolution CTX-M-14 complex structure at pH 7.9 revealed a neutral state for both Lys73 and Glu166. Furthermore, the avibactam hydroxylamine-O-sulfonate group conformation varied according to pH, and this conformational switch appeared to correspond to a change in the Lys73 protonation state at low pH. In conjunction with computational analyses, our structures suggest that Lys73 has a perturbed acid dissociation constant (pKa) compared with acyl-enzyme complexes with β-lactams, hindering its function to deprotonate Glu166 and the initiation of the deacylation reaction. Further NMR analysis demonstrated Lys73 pKa to be ∼5.2 to 5.6. Together with previous ultrahigh-resolution crystal structures, these findings enable us to follow the proton transfer process of the entire acylation reaction and reveal the critical role of Lys73. They also shed light on the stability and reversibility of the avibactam carbamoyl acyl-enzyme complex, highlighting the effect of substrate functional groups in influencing the protonation states of catalytic residues and subsequently the progression of the reaction.
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9
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β-Lactamase of Mycobacterium tuberculosis Shows Dynamics in the Active Site That Increase upon Inhibitor Binding. Antimicrob Agents Chemother 2020; 64:AAC.02025-19. [PMID: 31871087 DOI: 10.1128/aac.02025-19] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 12/19/2019] [Indexed: 12/11/2022] Open
Abstract
The Mycobacterium tuberculosis β-lactamase BlaC is a broad-spectrum β-lactamase that can convert a range of β-lactam antibiotics. Enzymes with low specificity are expected to exhibit active-site flexibility. To probe the motions in BlaC, we studied the dynamic behavior in solution using nuclear magnetic resonance (NMR) spectroscopy. 15N relaxation experiments show that BlaC is mostly rigid on the pico- to nanosecond timescale. Saturation transfer experiments indicate that also on the high-millisecond timescale BlaC is not dynamic. Using relaxation dispersion experiments, clear evidence was obtained for dynamics in the low-millisecond range, with an exchange rate of ca. 860 s-1 The dynamic amide groups are localized in the active site. Upon formation of an adduct with the inhibitor avibactam, extensive line broadening occurs, indicating an increase in magnitude of the active-site dynamics. Furthermore, the rate of the motions increases significantly. Upon reaction with the inhibitor clavulanic acid, similar line broadening is accompanied by duplication of NMR signals, indicative of at least one additional, slower exchange process (exchange rate, k ex, of <100 s-1), while for this inhibitor also loss of pico- to nanosecond timescale rigidity is observed for some amides in the α domain. Possible sources of the observed dynamics, such as motions in the omega loop and rearrangements of active-site residues, are discussed. The increase in dynamics upon ligand binding argues against a model of inhibitor binding through conformational selection. Rather, the induced dynamics may serve to maximize the likelihood of sampling the optimal conformation for hydrolysis of the bound ligand.
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10
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Dynamical Behavior of β-Lactamases and Penicillin- Binding Proteins in Different Functional States and Its Potential Role in Evolution. ENTROPY 2019. [PMCID: PMC7514474 DOI: 10.3390/e21111130] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
β-Lactamases are enzymes produced by bacteria to hydrolyze β-lactam-based antibiotics, and pose serious threat to public health through related antibiotic resistance. Class A β-lactamases are structurally and functionally related to penicillin-binding proteins (PBPs). Despite the extensive studies of the structures, catalytic mechanisms and dynamics of both β-lactamases and PBPs, the potentially different dynamical behaviors of these proteins in different functional states still remain elusive in general. In this study, four evolutionarily related proteins, including TEM-1 and TOHO-1 as class A β-lactamases, PBP-A and DD-transpeptidase as two PBPs, are subjected to molecular dynamics simulations and various analyses to characterize their dynamical behaviors in different functional states. Penicillin G and its ring opening product serve as common ligands for these four proteins of interest. The dynamic analyses of overall structures, the active sites with penicillin G, and three catalytically important residues commonly shared by all four proteins reveal unexpected cross similarities between Class A β-lactamases and PBPs. These findings shed light on both the hidden relations among dynamical behaviors of these proteins and the functional and evolutionary relations among class A β-lactamases and PBPs.
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11
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Wang F, Shen L, Zhou H, Wang S, Wang X, Tao P. Machine Learning Classification Model for Functional Binding Modes of TEM-1 β-Lactamase. Front Mol Biosci 2019; 6:47. [PMID: 31355207 PMCID: PMC6629954 DOI: 10.3389/fmolb.2019.00047] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2019] [Accepted: 06/11/2019] [Indexed: 11/13/2022] Open
Abstract
TEM family of enzymes is one of the most commonly encountered β-lactamases groups with different catalytic capabilities against various antibiotics. Despite the studies investigating the catalytic mechanism of TEM β-lactamases, the binding modes of these enzymes against ligands in different functional catalytic states have been largely overlooked. But the binding modes may play a critical role in the function and even the evolution of these proteins. In this work, a newly developed machine learning analysis approach to the recognition of protein dynamics states was applied to compare the binding modes of TEM-1 β-lactamase with regard to penicillin in different catalytic states. While conventional analysis methods, including principal components analysis (PCA), could not differentiate TEM-1 in different binding modes, the application of a machine learning method led to excellent classification models differentiating these states. It was also revealed that both reactant/product states and apo/product states are more differentiable than the apo/reactant states. The feature importance generated by the training procedure of the machine learning model was utilized to evaluate the contribution from residues at active sites and in different secondary structures. Key active site residues, Ser70 and Ser130, play a critical role in differentiating reactant/product states, while other active site residues are more important for differentiating apo/product states. Overall, this study provides new insights into the different dynamical function states of TEM-1 and may open a new venue for β-lactamases functional and evolutional studies in general.
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Affiliation(s)
- Feng Wang
- Department of Chemistry, Center for Scientific Computation, Center for Drug Discovery, Design, and Delivery (CD4), Southern Methodist University, Dallas, TX, United States
| | - Li Shen
- Department of Chemistry, Center for Scientific Computation, Center for Drug Discovery, Design, and Delivery (CD4), Southern Methodist University, Dallas, TX, United States
| | - Hongyu Zhou
- Department of Chemistry, Center for Scientific Computation, Center for Drug Discovery, Design, and Delivery (CD4), Southern Methodist University, Dallas, TX, United States
| | - Shouyi Wang
- Department of Industrial, Manufacturing, and Systems Engineering, University of Texas at Arlington, Arlington, TX, United States
| | - Xinlei Wang
- Department of Statistical Science, Southern Methodist University, Dallas, TX, United States
| | - Peng Tao
- Department of Chemistry, Center for Scientific Computation, Center for Drug Discovery, Design, and Delivery (CD4), Southern Methodist University, Dallas, TX, United States
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Mojica MF, Rutter JD, Taracila M, Abriata LA, Fouts DE, Papp-Wallace KM, Walsh TJ, LiPuma JJ, Vila AJ, Bonomo RA. Population Structure, Molecular Epidemiology, and β-Lactamase Diversity among Stenotrophomonas maltophilia Isolates in the United States. mBio 2019; 10:e00405-19. [PMID: 31266860 PMCID: PMC6606795 DOI: 10.1128/mbio.00405-19] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 06/03/2019] [Indexed: 01/06/2023] Open
Abstract
Stenotrophomonas maltophilia is a Gram-negative, nonfermenting, environmental bacillus that is an important cause of nosocomial infections, primarily associated with the respiratory tract in the immunocompromised population. Aiming to understand the population structure, microbiological characteristics and impact of allelic variation on β-lactamase structure and function, we collected 130 clinical isolates from across the United States. Identification of 90 different sequence types (STs), of which 63 are new allelic combinations, demonstrates the high diversity of this species. The majority of the isolates (45%) belong to genomic group 6. We also report excellent activity of the ceftazidime-avibactam and aztreonam combination, especially against strains recovered from blood and respiratory infections for which the susceptibility is higher than the susceptibility to trimethoprim-sulfamethoxazole, considered the "first-line" antibiotic to treat S. maltophilia Analysis of 73 blaL1 and 116 blaL2 genes identified 35 and 43 novel variants of L1 and L2 β-lactamases, respectively. Investigation of the derived amino acid sequences showed that substitutions are mostly conservative and scattered throughout the protein, preferentially affecting positions that do not compromise enzyme function but that may have an impact on substrate and inhibitor binding. Interestingly, we detected a probable association between a specific type of L1 and L2 and genomic group 6. Taken together, our results provide an overview of the molecular epidemiology of S. maltophilia clinical strains from the United States. In particular, the discovery of new L1 and L2 variants warrants further study to fully understand the relationship between them and the β-lactam resistance phenotype in this pathogen.IMPORTANCE Multiple antibiotic resistance mechanisms, including two β-lactamases, L1, a metallo-β-lactamase, and L2, a class A cephalosporinase, make S. maltophilia naturally multidrug resistant. Thus, infections caused by S. maltophilia pose a big therapeutic challenge. Our study aims to understand the microbiological and molecular characteristics of S. maltophilia isolates recovered from human sources. A highlight of the resistance profile of this collection is the excellent activity of the ceftazidime-avibactam and aztreonam combination. We hope this result prompts controlled and observational studies to add clinical data on the utility and safety of this therapy. We also identify 35 and 43 novel variants of L1 and L2, respectively, some of which harbor novel substitutions that could potentially affect substrate and/or inhibitor binding. We believe our results provide valuable knowledge to understand the epidemiology of this species and to advance mechanism-based inhibitor design to add to the limited arsenal of antibiotics active against this pathogen.
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Affiliation(s)
- Maria F Mojica
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Joseph D Rutter
- Research Service, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio, USA
| | - Magdalena Taracila
- Research Service, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Luciano A Abriata
- Laboratory for Biomolecular Modeling, Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | - Krisztina M Papp-Wallace
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Research Service, Louis Stokes Veterans Affairs Medical Center, Cleveland, Ohio, USA
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
| | - Thomas J Walsh
- Transplantation Oncology Infectious Diseases Program, Weill Cornell Medical Center, New York, New York, USA
| | - John J LiPuma
- Department of Pediatrics, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Alejandro J Vila
- Instituto de Biología Molecular y Celular de Rosario (IBR, CONICET-UNR), Rosario, Argentina
| | - Robert A Bonomo
- Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Pharmacology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Department of Biochemistry, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Center for Proteomics and Bioinformatics, Case Western Reserve University School of Medicine, Cleveland, Ohio, USA
- Medical Service, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
- GRECC, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland, Ohio, USA
- CWRU-Cleveland VAMC Center for Antimicrobial Resistance and Epidemiology (Case VA CARES), Cleveland, Ohio, USA
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13
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Shurina BA, Page RC. Influence of substrates and inhibitors on the structure of Klebsiella pneumoniae carbapenemase-2. Exp Biol Med (Maywood) 2019; 244:1596-1604. [PMID: 31161945 DOI: 10.1177/1535370219854322] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The hydrolysis of last resort carbapenem antibiotics by Klebsiella pneumoniae carbapenemase-2 (KPC-2) presents a significant danger to global health. Combined with horizontal gene transfer, the emergence KPC-2 threatens to quickly expand carbapenemase activity to ever increasing numbers of pathogens. Our understanding of KPC-2 has greatly increased over the past decade thanks, in great part, to 20 crystal structures solved by groups around the world. These include apo KPC-2 structures, along with structures featuring a library of 10 different inhibitors representing diverse structural and functional classes. Herein we focus on cataloging the available KPC-2 structures and presenting a discussion of key aspects of each structure and important relationships between structures. Although the available structures do not provide information on dynamic motions with KPC-2, and the family of structures indicates small conformational changes across a wide array of bound inhibitors, substrates, and products, the structures provide a strong foundation for additional studies in the coming years to discover new KPC-2 inhibitors. Impact statement The work herein is important to the field as it provides a clear and succinct accounting of available KPC-2 structures. The work advances the field by collecting and analyzing differences and similarities across the available structures. This work features new analyses and interpretations of the existing structures which will impact the field in a positive way by making structural insights more widely available among the beta-lactamase community.
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Affiliation(s)
- Ben A Shurina
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Richard C Page
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
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14
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Hartley AM, Zaki AJ, McGarrity AR, Robert-Ansart C, Moskalenko AV, Jones GF, Craciun MF, Russo S, Elliott M, Macdonald JE, Jones DD. Functional modulation and directed assembly of an enzyme through designed non-natural post-translation modification. Chem Sci 2015; 6:3712-3717. [PMID: 28706718 PMCID: PMC5496188 DOI: 10.1039/c4sc03900a] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 03/31/2015] [Indexed: 11/21/2022] Open
Abstract
Designed phenyl azide incorporation combined with bioorthogonal Click chemistry to regulate enzyme activity, or promote its stable assembly on graphene.
Post-translational modification (PTM) modulates and supplements protein functionality. In nature this high precision event requires specific motifs and/or associated modification machinery. To overcome the inherent complexity that hinders PTM's wider use, we have utilized a non-native biocompatible Click chemistry approach to site-specifically modify TEM β-lactamase that adds new functionality. In silico modelling was used to design TEM β-lactamase variants with the non-natural amino acid p-azido-l-phenylalanine (azF) placed at functionally strategic positions permitting residue-specific modification with alkyne adducts by exploiting strain-promoted azide–alkyne cycloaddition. Three designs were implemented so that the modification would: (i) inhibit TEM activity (Y105azF); (ii) restore activity compromised by the initial mutation (P174azF); (iii) facilitate assembly on pristine graphene (W165azF). A dibenzylcyclooctyne (DBCO) with amine functionality was enough to modulate enzymatic activity. Modification of TEMW165azF with a DBCO–pyrene adduct had little effect on activity despite the modification site being close to a key catalytic residue but allowed directed assembly of the enzyme on graphene, potentially facilitating the construction of protein-gated carbon transistor systems.
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Affiliation(s)
| | - Athraa J Zaki
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales , UK
| | | | | | | | - Gareth F Jones
- Centre for Graphene Science , University of Exeter , Exeter , Devon , UK
| | - Monica F Craciun
- Centre for Graphene Science , University of Exeter , Exeter , Devon , UK
| | - Saverio Russo
- Centre for Graphene Science , University of Exeter , Exeter , Devon , UK
| | - Martin Elliott
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales , UK
| | - J Emyr Macdonald
- School of Physics and Astronomy , Cardiff University , Cardiff , Wales , UK
| | - D Dafydd Jones
- School of Biosciences , Cardiff University , Cardiff , UK .
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15
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Gagné D, Narayanan C, Doucet N. Network of long-range concerted chemical shift displacements upon ligand binding to human angiogenin. Protein Sci 2014; 24:525-33. [PMID: 25450558 DOI: 10.1002/pro.2613] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 11/25/2014] [Indexed: 11/11/2022]
Abstract
Molecular recognition models of both induced fit and conformational selection rely on coupled networks of flexible residues and/or structural rearrangements to promote protein function. While the atomic details of these motional events still remain elusive, members of the pancreatic ribonuclease superfamily were previously shown to depend on subtle conformational heterogeneity for optimal catalytic function. Human angiogenin, a structural homologue of bovine pancreatic RNase A, induces blood vessel formation and relies on a weak yet functionally mandatory ribonucleolytic activity to promote neovascularization. Here, we use the NMR chemical shift projection analysis (CHESPA) to clarify the mechanism of ligand binding in human angiogenin, further providing information on long-range intramolecular residue networks potentially involved in the function of this enzyme. We identify two main clusters of residue networks displaying correlated linear chemical shift trajectories upon binding of substrate fragments to the purine- and pyrimidine-specific subsites of the catalytic cleft. A large correlated residue network clusters in the region corresponding to the V1 domain, a site generally associated with the angiogenic response and structural stability of the enzyme. Another correlated network (residues 40-42) negatively affects the catalytic activity but also increases the angiogenic activity. (15) N-CPMG relaxation dispersion experiments could not reveal the existence of millisecond timescale conformational exchange in this enzyme, a lack of flexibility supported by the very low-binding affinities and catalytic activity of angiogenin. Altogether, the current report potentially highlights the existence of long-range dynamic reorganization of the structure upon distinct subsite binding events in human angiogenin.
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Affiliation(s)
- Donald Gagné
- INRS-Institut Armand-Frappier, Université du Québec, 531 Boulevard des Prairies, Laval, Québec, H7V 1B7, Canada
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16
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Zou T, Risso VA, Gavira JA, Sanchez-Ruiz JM, Ozkan SB. Evolution of conformational dynamics determines the conversion of a promiscuous generalist into a specialist enzyme. Mol Biol Evol 2014; 32:132-43. [PMID: 25312912 DOI: 10.1093/molbev/msu281] [Citation(s) in RCA: 101] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
β-Lactamases are produced by many modern bacteria as a mechanism of resistance toward β-lactam antibiotics, the most common antibiotics in use. β-Lactamases, however, are ancient enzymes that originated billions of years ago. Recently, proteins corresponding to 2- to 3-Gy-old Precambrian nodes in the evolution of Class A β-lactamases have been prepared and shown to be moderately efficient promiscuous catalysts, able to degrade a variety of antibiotics with catalytic efficiency levels similar to those of an average modern enzyme. Remarkably, there are few structural differences (in particular at the active-site regions) between the resurrected enzymes and a penicillin-specialist modern β-lactamase. Here, we propose that the ancestral promiscuity originates from conformational dynamics. We investigate the differences in conformational dynamics of the ancient and extant β-lactamases through MD simulations and quantify the contribution of each position to functionally related dynamics through Dynamic Flexibility Index. The modern TEM-1 lactamase shows a comparatively rigid active-site region, likely reflecting adaptation for efficient degradation of a specific substrate (penicillin), whereas enhanced deformability at the active-site neighborhood in the ancestral resurrected proteins likely accounts for the binding and subsequent degradation of antibiotic molecules of different size and shape. Clustering of the conformational dynamics on the basis of Principal Component Analysis is in agreement with the functional divergence, as the ancient β-lactamases cluster together, separated from their modern descendant. Finally, our analysis leads to testable predictions, as sites of potential relevance for the evolution of dynamics are identified and mutations at those sites are expected to alter substrate-specificity.
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Affiliation(s)
- Taisong Zou
- Center for Biological Physics, Department of Physics, Arizona State University
| | - Valeria A Risso
- Departamento de Química Física, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - Jose A Gavira
- Laboratorio de Estudios Cristalográficos, Instituto Andaluz de Ciencias de la Tierra (Consejo Superior de Investigaciones Científicas-Universidad de Granada), Granada, Spain
| | - Jose M Sanchez-Ruiz
- Departamento de Química Física, Facultad de Ciencias, Universidad de Granada, Granada, Spain
| | - S Banu Ozkan
- Center for Biological Physics, Department of Physics, Arizona State University
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17
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Gobeil SMC, Clouthier CM, Park J, Gagné D, Berghuis AM, Doucet N, Pelletier JN. Maintenance of native-like protein dynamics may not be required for engineering functional proteins. ACTA ACUST UNITED AC 2014; 21:1330-1340. [PMID: 25200606 DOI: 10.1016/j.chembiol.2014.07.016] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 06/27/2014] [Accepted: 07/09/2014] [Indexed: 12/16/2022]
Abstract
Proteins are dynamic systems, and understanding dynamics is critical for fully understanding protein function. Therefore, the question of whether laboratory engineering has an impact on protein dynamics is of general interest. Here, we demonstrate that two homologous, naturally evolved enzymes with high degrees of structural and functional conservation also exhibit conserved dynamics. Their similar set of slow timescale dynamics is highly restricted, consistent with evolutionary conservation of a functionally important feature. However, we also show that dynamics of a laboratory-engineered chimeric enzyme obtained by recombination of the two homologs exhibits striking difference on the millisecond timescale, despite function and high-resolution crystal structure (1.05 Å) being conserved. The laboratory-engineered chimera is thus functionally tolerant to modified dynamics on the timescale of catalytic turnover. Tolerance to dynamic variation implies that maintenance of native-like protein dynamics may not be required when engineering functional proteins.
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Affiliation(s)
- Sophie M C Gobeil
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; Département de Biochimie, Université de Montréal, Montréal QC H3T 1J4, Canada
| | - Christopher M Clouthier
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; Département de Chimie, Université de Montréal, Montréal QC H3T 1J4, Canada
| | - Jaeok Park
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; Department of Biochemistry and Department of Microbiology and Immunology, McGill University, Montreal QC H3G 1Y6, Canada; GRASP Network, McGill University, Montréal QC H3G 1Y6, Canada
| | - Donald Gagné
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; GRASP Network, McGill University, Montréal QC H3G 1Y6, Canada; INRS-Institut Armand-Frappier, Université du Québec, Laval QC H7V 1B7, Canada
| | - Albert M Berghuis
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; Department of Biochemistry and Department of Microbiology and Immunology, McGill University, Montreal QC H3G 1Y6, Canada; GRASP Network, McGill University, Montréal QC H3G 1Y6, Canada
| | - Nicolas Doucet
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; GRASP Network, McGill University, Montréal QC H3G 1Y6, Canada; INRS-Institut Armand-Frappier, Université du Québec, Laval QC H7V 1B7, Canada
| | - Joelle N Pelletier
- PROTEO Network, Université Laval, Québec QC G1V 0A6, Canada; Département de Biochimie, Université de Montréal, Montréal QC H3T 1J4, Canada; Département de Chimie, Université de Montréal, Montréal QC H3T 1J4, Canada; Center for Green Chemistry and Catalysis (CCVC), Montréal QC H3A 0B8, Canada.
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18
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Clouthier CM, Morin S, Gobeil SMC, Doucet N, Blanchet J, Nguyen E, Gagné SM, Pelletier JN. Chimeric β-lactamases: global conservation of parental function and fast time-scale dynamics with increased slow motions. PLoS One 2012; 7:e52283. [PMID: 23284969 PMCID: PMC3528772 DOI: 10.1371/journal.pone.0052283] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2012] [Accepted: 11/15/2012] [Indexed: 11/18/2022] Open
Abstract
Enzyme engineering has been facilitated by recombination of close homologues, followed by functional screening. In one such effort, chimeras of two class-A β-lactamases – TEM-1 and PSE-4 – were created according to structure-guided protein recombination and selected for their capacity to promote bacterial proliferation in the presence of ampicillin (Voigt et al., Nat. Struct. Biol. 2002 9:553). To provide a more detailed assessment of the effects of protein recombination on the structure and function of the resulting chimeric enzymes, we characterized a series of functional TEM-1/PSE-4 chimeras possessing between 17 and 92 substitutions relative to TEM-1 β-lactamase. Circular dichroism and thermal scanning fluorimetry revealed that the chimeras were generally well folded. Despite harbouring important sequence variation relative to either of the two ‘parental’ β-lactamases, the chimeric β-lactamases displayed substrate recognition spectra and reactivity similar to their most closely-related parent. To gain further insight into the changes induced by chimerization, the chimera with 17 substitutions was investigated by NMR spin relaxation. While high order was conserved on the ps-ns timescale, a hallmark of class A β-lactamases, evidence of additional slow motions on the µs-ms timescale was extracted from model-free calculations. This is consistent with the greater number of resonances that could not be assigned in this chimera relative to the parental β-lactamases, and is consistent with this well-folded and functional chimeric β-lactamase displaying increased slow time-scale motions.
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Affiliation(s)
- Christopher M. Clouthier
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Chimie, Université de Montréal, Montréal, Québec, Canada
| | - Sébastien Morin
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Laval Québec, Canada
| | - Sophie M. C. Gobeil
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Biochimie, Université de Montréal, Montréal, Québec, Canada
| | - Nicolas Doucet
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- INRS–Institut Armand-Frappier, Université du Québec, Laval, Québec, Canada
| | - Jonathan Blanchet
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Chimie, Université de Montréal, Montréal, Québec, Canada
| | - Elisabeth Nguyen
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Chimie, Université de Montréal, Montréal, Québec, Canada
| | - Stéphane M. Gagné
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Biochimie, Microbiologie et Bioinformatique, Université Laval, Laval Québec, Canada
| | - Joelle N. Pelletier
- PROTEO, the Québec Network for Research on Protein Structure, Function and Engineering, Université Laval, Laval, Québec, Canada
- Département de Chimie, Université de Montréal, Montréal, Québec, Canada
- Département de Biochimie, Université de Montréal, Montréal, Québec, Canada
- * E-mail:
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19
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Gagné D, Charest LA, Morin S, Kovrigin EL, Doucet N. Conservation of flexible residue clusters among structural and functional enzyme homologues. J Biol Chem 2012; 287:44289-300. [PMID: 23135272 DOI: 10.1074/jbc.m112.394866] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Conformational flexibility between structural ensembles is an essential component of enzyme function. Although the broad dynamical landscape of proteins is known to promote a number of functional events on multiple time scales, it is yet unknown whether structural and functional enzyme homologues rely on the same concerted residue motions to perform their catalytic function. It is hypothesized that networks of contiguous and flexible residue motions occurring on the biologically relevant millisecond time scale evolved to promote and/or preserve optimal enzyme catalysis. In this study, we use a combination of NMR relaxation dispersion, model-free analysis, and ligand titration experiments to successfully capture and compare the role of conformational flexibility between two structural homologues of the pancreatic ribonuclease family: RNase A and eosinophil cationic protein (or RNase 3). In addition to conserving the same catalytic residues and structural fold, both homologues show similar yet functionally distinct clusters of millisecond dynamics, suggesting that conformational flexibility can be conserved among analogous protein folds displaying low sequence identity. Our work shows that the reduced conformational flexibility of eosinophil cationic protein can be dynamically and functionally reproduced in the RNase A scaffold upon creation of a chimeric hybrid between the two proteins. These results support the hypothesis that conformational flexibility is partly required for catalytic function in homologous enzyme folds, further highlighting the importance of dynamic residue sectors in the structural organization of proteins.
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Affiliation(s)
- Donald Gagné
- Institut National de la Recherche Scientifique-Institut Armand-Frappier, Université du Québec, Laval, Quebec H7V 1B7, Canada
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20
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Fisette O, Gagné S, Lagüe P. Molecular dynamics of class A β-lactamases-effects of substrate binding. Biophys J 2012; 103:1790-801. [PMID: 23083723 DOI: 10.1016/j.bpj.2012.09.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Revised: 09/07/2012] [Accepted: 09/11/2012] [Indexed: 11/18/2022] Open
Abstract
The effects of substrate binding on class A β-lactamase dynamics were studied using molecular dynamics simulations of two model enzymes; 40 100-ns trajectories of the free and substrate-bound forms of TEM-1 (with benzylpenicillin) and PSE-4 (with carbenicillin) were recorded (totaling 4.0 μs). Substrates were parameterized with the CHARMM General Force Field. In both enzymes, the Ω loop exhibits a marked flexibility increase upon substrate binding, supporting the hypothesis of substrate gating. However, specific interactions that are formed or broken in the Ω loop upon binding differ between the two enzymes: dynamics are conserved, but not specific interactions. Substrate binding also has a global structuring effect on TEM-1, but not on PSE-4. Changes in TEM-1's normal modes show long-range effects of substrate binding on enzyme dynamics. Hydrogen bonds observed in the active site are mostly preserved upon substrate binding, and new, transient interactions are also formed. Agreement between NMR relaxation parameters and our theoretical results highlights the dynamic duality of class A β-lactamases: enzymes that are highly structured on the ps-ns timescale, with important flexibility on the μs-ms timescale in regions such as the Ω loop.
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Affiliation(s)
- Olivier Fisette
- Département de Biochimie et de Mcrobiologie, Université Laval and PROTEO and IBIS, Québec (QC), Canada
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21
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Substitutions at position 105 in SHV family β-lactamases decrease catalytic efficiency and cause inhibitor resistance. Antimicrob Agents Chemother 2012; 56:5678-86. [PMID: 22908166 DOI: 10.1128/aac.00711-12] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Ambler position 105 in class A β-lactamases is implicated in resistance to clavulanic acid, although no clinical isolates with mutations at this site have been reported. We hypothesized that Y105 is important in resistance to clavulanic acid because changes in positioning of the inhibitor for ring oxygen protonation could occur. In addition, resistance to bicyclic 6-methylidene penems, which are interesting structural probes that inhibit all classes of serine β-lactamases with nanomolar affinity, might emerge with substitutions at position 105, especially with nonaromatic substitutions. All 19 variants of SHV-1 with variations at position 105 were prepared. Antimicrobial susceptibility testing showed that Escherichia coli DH10B expressing Y105 variants retained activity against ampicillin, except for the Y105L variant, which was susceptible to all β-lactams, similar to the case for the host control strain. Several variants had elevated MICs to ampicillin-clavulanate. However, all the variants remained susceptible to piperacillin in combination with a penem inhibitor (MIC, ≤2/4 mg/liter). The Y105E, -F, -M, and -R variants demonstrated reduced catalytic efficiency toward ampicillin compared to the wild-type (WT) enzyme, which was caused by increased K(m). Clavulanic acid and penem K(i) values were also increased for some of the variants, especially Y105E. Mutagenesis at position 105 in SHV yields mutants resistant to clavulanate with reduced catalytic efficiency for ampicillin and nitrocefin, similar to the case for the class A carbapenemase KPC-2. Our modeling analyses suggest that resistance is due to oxyanion hole distortion. Susceptibility to a penem inhibitor is retained although affinity is decreased, especially for the Y105E variant. Residue 105 is important to consider when designing new inhibitors.
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22
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Papp-Wallace KM, Taracila M, Wallace CJ, Hujer KM, Bethel CR, Hornick JM, Bonomo RA. Elucidating the role of Trp105 in the KPC-2 β-lactamase. Protein Sci 2011; 19:1714-27. [PMID: 20662006 DOI: 10.1002/pro.454] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The molecular basis of resistance to β-lactams and β-lactam-β-lactamase inhibitor combinations in the KPC family of class A enzymes is of extreme importance to the future design of effective β-lactam therapy. Recent crystal structures of KPC-2 and other class A β-lactamases suggest that Ambler position Trp105 may be of importance in binding β-lactam compounds. Based on this notion, we explored the role of residue Trp105 in KPC-2 by conducting site-saturation mutagenesis at this position. Escherichia coli DH10B cells expressing the Trp105Phe, -Tyr, -Asn, and -His KPC-2 variants possessed minimal inhibitory concentrations (MICs) similar to E. coli cells expressing wild type (WT) KPC-2. Interestingly, most of the variants showed increased MICs to ampicillin-clavulanic acid but not to ampicillin-sulbactam or piperacillin-tazobactam. To explain the biochemical basis of this behavior, four variants (Trp105Phe, -Asn, -Leu, and -Val) were studied in detail. Consistent with the MIC data, the Trp105Phe β-lactamase displayed improved catalytic efficiencies, k(cat)/K(m), toward piperacillin, cephalothin, and nitrocefin, but slightly decreased k(cat)/K(m) toward cefotaxime and imipenem when compared to WT β-lactamase. The Trp105Asn variant exhibited increased K(m)s for all substrates. In contrast, the Trp105Leu and -Val substituted enzymes demonstrated notably decreased catalytic efficiencies (k(cat)/K(m)) for all substrates. With respect to clavulanic acid, the K(i)s and partition ratios were increased for the Trp105Phe, -Asn, and -Val variants. We conclude that interactions between Trp105 of KPC-2 and the β-lactam are essential for hydrolysis of substrates. Taken together, kinetic and molecular modeling studies define the role of Trp105 in β-lactam and β-lactamase inhibitor discrimination.
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23
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Bellemare A, Vernoux N, Morin S, Gagné SM, Bourbonnais Y. Structural and antimicrobial properties of human pre-elafin/trappin-2 and derived peptides against Pseudomonas aeruginosa. BMC Microbiol 2010; 10:253. [PMID: 20932308 PMCID: PMC2958999 DOI: 10.1186/1471-2180-10-253] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 10/08/2010] [Indexed: 11/10/2022] Open
Abstract
Background Pre-elafin/trappin-2 is a human innate defense molecule initially described as a potent inhibitor of neutrophil elastase. The full-length protein as well as the N-terminal "cementoin" and C-terminal "elafin" domains were also shown to possess broad antimicrobial activity, namely against the opportunistic pathogen P. aeruginosa. The mode of action of these peptides has, however, yet to be fully elucidated. Both domains of pre-elafin/trappin-2 are polycationic, but only the structure of the elafin domain is currently known. The aim of the present study was to determine the secondary structures of the cementoin domain and to characterize the antibacterial properties of these peptides against P. aeruginosa. Results We show here that the cementoin domain adopts an α-helical conformation both by circular dichroism and nuclear magnetic resonance analyses in the presence of membrane mimetics, a characteristic shared with a large number of linear polycationic antimicrobial peptides. However, pre-elafin/trappin-2 and its domains display only weak lytic properties, as assessed by scanning electron micrography, outer and inner membrane depolarization studies with P. aeruginosa and leakage of liposome-entrapped calcein. Confocal microscopy of fluorescein-labeled pre-elafin/trappin-2 suggests that this protein possesses the ability to translocate across membranes. This correlates with the finding that pre-elafin/trappin-2 and elafin bind to DNA in vitro and attenuate the expression of some P. aeruginosa virulence factors, namely the biofilm formation and the secretion of pyoverdine. Conclusions The N-terminal cementoin domain adopts α-helical secondary structures in a membrane mimetic environment, which is common in antimicrobial peptides. However, unlike numerous linear polycationic antimicrobial peptides, membrane disruption does not appear to be the main function of either cementoin, elafin or full-length pre-elafin/trappin-2 against P. aeruginosa. Our results rather suggest that pre-elafin/trappin-2 and elafin, but not cementoin, possess the ability to modulate the expression of some P.aeruginosa virulence factors, possibly through acting on intracellular targets.
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Affiliation(s)
- Audrey Bellemare
- Département de Biochimie, Microbiologie et Bio-informatique, Institut de Biologie Intégrative et des Systèmes and Regroupement PROTEO, Université Laval, Québec, Canada
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24
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Fisette O, Morin S, Savard PY, Lagüe P, Gagné SM. TEM-1 backbone dynamics-insights from combined molecular dynamics and nuclear magnetic resonance. Biophys J 2010; 98:637-45. [PMID: 20159160 DOI: 10.1016/j.bpj.2009.08.061] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2009] [Revised: 08/24/2009] [Accepted: 08/25/2009] [Indexed: 11/28/2022] Open
Abstract
Dynamic properties of class A beta-lactamase TEM-1 are investigated from molecular dynamics (MD) simulations. Comparison of MD-derived order parameters with those obtained from model-free analysis of nuclear magnetic resonance (NMR) relaxation data shows high agreement for N-H moieties within alpha- and beta-secondary structures, but significant deviation for those in loops. This was expected, because motions slower than the protein global tumbling often take place in loop regions. As previously shown using NMR, TEM-1 is a highly ordered protein. Motions are observed within the Omega loop that could, upon substrate binding, stabilize E166 in a catalytically efficient position as the cavity between the protein core and the Omega loop is partially filled. The rigidity of active site residues is consistent with the enzyme high turnover number. MD data are also shown to be useful during the model selection step of model-free analysis: local N-H motions observed over the course of the trajectories help assess whether a peptide plan undergoes low or high amplitude motions on one or more timescales. This joint use of MD and NMR provides a better description of protein dynamics than would be possible using either technique alone.
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Affiliation(s)
- Olivier Fisette
- Département de Biochimie et de Microbiologie, Université Laval and PROTEO, Québec, Canada
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Poliakov E, Gentleman S, Chander P, Cunningham FX, Grigorenko BL, Nemuhin AV, Redmond TM. Biochemical evidence for the tyrosine involvement in cationic intermediate stabilization in mouse beta-carotene 15, 15'-monooxygenase. BMC BIOCHEMISTRY 2009; 10:31. [PMID: 20003456 PMCID: PMC2801523 DOI: 10.1186/1471-2091-10-31] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 12/14/2009] [Indexed: 11/10/2022]
Abstract
Background β-carotene 15,15'-monooxygenase (BCMO1) catalyzes the crucial first step in vitamin A biosynthesis in animals. We wished to explore the possibility that a carbocation intermediate is formed during the cleavage reaction of BCMO1, as is seen for many isoprenoid biosynthesis enzymes, and to determine which residues in the substrate binding cleft are necessary for catalytic and substrate binding activity. To test this hypothesis, we replaced substrate cleft aromatic and acidic residues by site-directed mutagenesis. Enzymatic activity was measured in vitro using His-tag purified proteins and in vivo in a β-carotene-accumulating E. coli system. Results Our assays show that mutation of either Y235 or Y326 to leucine (no cation-π stabilization) significantly impairs the catalytic activity of the enzyme. Moreover, mutation of Y326 to glutamine (predicted to destabilize a putative carbocation) almost eliminates activity (9.3% of wt activity). However, replacement of these same tyrosines with phenylalanine or tryptophan does not significantly impair activity, indicating that aromaticity at these residues is crucial. Mutations of two other aromatic residues in the binding cleft of BCMO1, F51 and W454, to either another aromatic residue or to leucine do not influence the catalytic activity of the enzyme. Our ab initio model of BCMO1 with β-carotene mounted supports a mechanism involving cation-π stabilization by Y235 and Y326. Conclusions Our data are consistent with the formation of a substrate carbocation intermediate and cation-π stabilization of this intermediate by two aromatic residues in the substrate-binding cleft of BCMO1.
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Morin S, Gagné SM. NMR dynamics of PSE-4 beta-lactamase: an interplay of ps-ns order and mus-ms motions in the active site. Biophys J 2009; 96:4681-91. [PMID: 19486690 DOI: 10.1016/j.bpj.2009.02.068] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Revised: 02/16/2009] [Accepted: 02/25/2009] [Indexed: 10/20/2022] Open
Abstract
The backbone dynamics for the 29.5 kDa class A beta-lactamase PSE-4 is presented. This solution NMR study was performed using multiple field (15)N spin relaxation and amide exchange data in the EX2 regime. Analysis was carried out with the relax program and includes the Lipari-Szabo model-free approach. Showing similarity to the homologous enzyme TEM-1, PSE-4 is very rigid on the ps-ns timescale, although slower mus-ms motions are present for several residues; this is especially true near the active site. However, significant dynamics differences exist between the two homologs for several important residues. Moreover, our data support the presence of a motion of the Omega loop first detected using molecular dynamics simulations on TEM-1. Thus, class A beta-lactamases appear to be a class of highly ordered proteins on the ps-ns timescale despite their efficient catalytic activity and high plasticity toward several different beta-lactam antibiotics. Most importantly, catalytically relevant mus-ms motions are present in the active site, suggesting an important role in catalysis.
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Affiliation(s)
- Sébastien Morin
- Département de Biochimie et de Microbiologie and PROTEO, Université Laval, Québec, Canada
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Volpato JP, Yachnin BJ, Blanchet J, Guerrero V, Poulin L, Fossati E, Berghuis AM, Pelletier JN. Multiple conformers in active site of human dihydrofolate reductase F31R/Q35E double mutant suggest structural basis for methotrexate resistance. J Biol Chem 2009; 284:20079-89. [PMID: 19478082 PMCID: PMC2740434 DOI: 10.1074/jbc.m109.018010] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Revised: 05/06/2009] [Indexed: 11/06/2022] Open
Abstract
Methotrexate is a slow, tight-binding, competitive inhibitor of human dihydrofolate reductase (hDHFR), an enzyme that provides key metabolites for nucleotide biosynthesis. In an effort to better characterize ligand binding in drug resistance, we have previously engineered hDHFR variant F31R/Q35E. This variant displays a >650-fold decrease in methotrexate affinity, while maintaining catalytic activity comparable to the native enzyme. To elucidate the molecular basis of decreased methotrexate affinity in the doubly substituted variant, we determined kinetic and inhibitory parameters for the simple variants F31R and Q35E. This demonstrated that the important decrease of methotrexate affinity in variant F31R/Q35E is a result of synergistic effects of the combined substitutions. To better understand the structural cause of this synergy, we obtained the crystal structure of hDHFR variant F31R/Q35E complexed with methotrexate at 1.7-A resolution. The mutated residue Arg-31 was observed in multiple conformers. In addition, seven native active-site residues were observed in more than one conformation, which is not characteristic of the wild-type enzyme. This suggests that increased residue disorder underlies the observed methotrexate resistance. We observe a considerable loss of van der Waals and polar contacts with the p-aminobenzoic acid and glutamate moieties. The multiple conformers of Arg-31 further suggest that the amino acid substitutions may decrease the isomerization step required for tight binding of methotrexate. Molecular docking with folate corroborates this hypothesis.
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Affiliation(s)
| | | | - Jonathan Blanchet
- the Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7 and
| | - Vanessa Guerrero
- the Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7 and
| | - Lucie Poulin
- the Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7 and
| | | | - Albert M. Berghuis
- the Departments of Biochemistry and
- Microbiology and Immunology, McGill University, Montréal, Québec H3G 0B1, Canada
| | - Joelle N. Pelletier
- From the Département de Biochimie and
- the Département de Chimie, Université de Montréal, Montréal, Québec H3C 3J7 and
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Bolduc OR, Masson JF. Monolayers of 3-mercaptopropyl-amino acid to reduce the nonspecific adsorption of serum proteins on the surface of biosensors. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:12085-91. [PMID: 18823086 DOI: 10.1021/la801861q] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Monolayers prepared with polar or ionic amino acids with short side chains have a reduced nonspecific adsorption of serum proteins compared to that of hydrophobic amino acids and organic monolayers immobilized on the gold surface of surface plasmon resonance (SPR) biosensors. Proteins contained in biological samples adsorb on most surfaces, which in the case of biosensors causes a nonspecific response that hinders the quantification of biomarkers in these biological samples. To circumvent this problem, self-assembled monolayers (SAM) of N-3-mercaptopropyl-amino acids (3-MPA-amino acids) were prepared from 19 natural amino acids. These SAM were investigated to limit the nonspecific adsorption of proteins contained in biological fluids and to immobilize molecular receptors (i.e., antibodies) that are necessary in the construction of biosensors. SPR and Ge attenuated total reflection (GATR) FTIR spectroscopy were employed to characterize the formation of the amino acid SAMs. Monolayers of 3-MPA-amino acids densely packed on the surface of the SPR biosensors result in a surface concentration of approximately 10 (15) molecules/cm (2). SPR also quantifies the surface concentration of serum proteins nonspecifically adsorbed on 3-MPA-amino acids following the exposure of the biosensor to undiluted bovine serum. The concentration of nonspecifically bound proteins ranged from approximately 400 ng/cm (2) with polar and ionic amino acids to approximately 800 ng/cm (2) with amino acids of increased hydrophobicity. The nonspecific adsorption of serum proteins on the 3-MPA-amino acids increases in the following order: Asp < Asn < Ser < Met < Glu < Gln < Thr < Gly < His < Cys < Arg < Phe < Trp < Val < Pro < Ile < Leu < Ala < Tyr. The analysis of the adsorption and desorption curves for serum proteins on the SPR sensorgram has demonstrated the strong irreversibility of the protein adsorption on each surface. The effective hydrophilicity of the SAMs was measured from the contact angle with a saline buffer and has demonstrated that surfaces minimizing the contact angle with PBS performed better in serum. The antibody for beta-lactamase was immobilized on a 3-MPA-glycine SAM, and beta-lactamase was detected in the nanomolar range. The presence of beta-lactamase is an indicator of antibiotic resistance.
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Affiliation(s)
- Olivier R Bolduc
- Département de Chimie, Université de Montréal, C. P. 6128 Succ. Centre-Ville, Montréal, Quebec, Canada H3C 3J7
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