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Kollár L, Grabrijan K, Hrast Rambaher M, Bozovičar K, Imre T, Ferenczy GG, Gobec S, Keserű GM. Boronic acid inhibitors of penicillin-binding protein 1b: serine and lysine labelling agents. J Enzyme Inhib Med Chem 2024; 39:2305833. [PMID: 38410950 PMCID: PMC10901194 DOI: 10.1080/14756366.2024.2305833] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 01/08/2024] [Indexed: 02/28/2024] Open
Abstract
Penicillin-binding proteins (PBPs) contribute to bacterial cell wall biosynthesis and are targets of antibacterial agents. Here, we investigated PBP1b inhibition by boronic acid derivatives. Chemical starting points were identified by structure-based virtual screening and aliphatic boronic acids were selected for further investigations. Structure-activity relationship studies focusing on the branching of the boron-connecting carbon and quantum mechanical/molecular mechanical simulations showed that reaction barrier free energies are compatible with fast reversible covalent binding and small or missing reaction free energies limit the inhibitory activity of the investigated boronic acid derivatives. Therefore, covalent labelling of the lysine residue of the catalytic dyad was also investigated. Compounds with a carbonyl warhead and an appropriately positioned boronic acid moiety were shown to inhibit and covalently label PBP1b. Reversible covalent labelling of the catalytic lysine by imine formation and the stabilisation of the imine by dative N-B bond is a new strategy for PBP1b inhibition.
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Affiliation(s)
- Levente Kollár
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
| | | | | | | | - Tímea Imre
- MS Metabolomics Research Group, Research Centre for Natural Sciences, Budapest, Hungary
| | - György G Ferenczy
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
| | - Stanislav Gobec
- Faculty of Pharmacy, University of Ljubljana, Ljubljana, Slovenia
| | - György M Keserű
- Medicinal Chemistry Research Group, Research Centre for Natural Sciences, Budapest, Hungary
- Department of Organic Chemistry and Technology, Faculty of Chemical Technology and Biotechnology, Budapest University of Technology and Economics, Budapest, Hungary
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2
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Grams RJ, Santos WL, Scorei IR, Abad-García A, Rosenblum CA, Bita A, Cerecetto H, Viñas C, Soriano-Ursúa MA. The Rise of Boron-Containing Compounds: Advancements in Synthesis, Medicinal Chemistry, and Emerging Pharmacology. Chem Rev 2024; 124:2441-2511. [PMID: 38382032 DOI: 10.1021/acs.chemrev.3c00663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/23/2024]
Abstract
Boron-containing compounds (BCC) have emerged as important pharmacophores. To date, five BCC drugs (including boronic acids and boroles) have been approved by the FDA for the treatment of cancer, infections, and atopic dermatitis, while some natural BCC are included in dietary supplements. Boron's Lewis acidity facilitates a mechanism of action via formation of reversible covalent bonds within the active site of target proteins. Boron has also been employed in the development of fluorophores, such as BODIPY for imaging, and in carboranes that are potential neutron capture therapy agents as well as novel agents in diagnostics and therapy. The utility of natural and synthetic BCC has become multifaceted, and the breadth of their applications continues to expand. This review covers the many uses and targets of boron in medicinal chemistry.
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Affiliation(s)
- R Justin Grams
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 900 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Webster L Santos
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 900 West Campus Drive, Blacksburg, Virginia 24061, United States
| | | | - Antonio Abad-García
- Academia de Fisiología y Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, 11340 Mexico City, Mexico
| | - Carol Ann Rosenblum
- Department of Chemistry and Virginia Tech Center for Drug Discovery, Virginia Tech, 900 West Campus Drive, Blacksburg, Virginia 24061, United States
| | - Andrei Bita
- Department of Pharmacognosy & Phytotherapy, Faculty of Pharmacy, University of Medicine and Pharmacy of Craiova, 2 Petru Rareş Street, 200349 Craiova, Romania
| | - Hugo Cerecetto
- Centro de Investigaciones Nucleares, Facultad de Ciencias, Universidad de la República, Mataojo 2055, 11400 Montevideo, Uruguay
| | - Clara Viñas
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus UAB, 08193 Bellaterra, Spain
| | - Marvin A Soriano-Ursúa
- Academia de Fisiología y Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina del Instituto Politécnico Nacional, Plan de San Luis y Díaz Mirón s/n, 11340 Mexico City, Mexico
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3
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Mojanaga OO, Acharya KR, Lloyd MD. Recombinant protein production for structural and kinetic studies: A case study using M. tuberculosis α-methylacyl-CoA racemase (MCR). Methods Enzymol 2023; 690:1-37. [PMID: 37858526 DOI: 10.1016/bs.mie.2023.07.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Modern drug discovery is a target-driven approach in which a particular protein such as an enzyme is implicated in the disease process. Commonly, small-molecule drugs are identified using screening, rational design, and structural biology approaches. Drug screening, testing and optimization is typically conducted in vitro, and copious amounts of protein are required. The advent of recombinant DNA technologies has resulted in a rise in proteins purified by affinity techniques, typically by incorporating an "affinity tag" at the N- or C-terminus. Use of these tagged proteins and affinity techniques comes with a host of issues. This chapter describes the production of an untagged enzyme, α-methylacyl-CoA racemase (MCR) from Mycobacterium tuberculosis, using a recombinant E. coli system. Purification of the enzyme on a 100 mg scale using tandem anion-exchange chromatographies (DEAE-sepharose and RESOURCE-Q columns), and size-exclusion chromatographies is described. A modified protocol allowing the purification of cationic proteins is also described, based on tandem cation-exchange chromatographies (using CM-sepharose and RESOURCE-S columns) and size-exclusion chromatographies. The resulting MCR protein is suitable for biochemical and structural biology applications. The described protocols have wide applicability to the purification of other recombinant proteins and enzymes without using affinity chromatography.
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Affiliation(s)
- Otsile O Mojanaga
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom
| | - K Ravi Acharya
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom.
| | - Matthew D Lloyd
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom.
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4
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Brooke H, Ghoshray M, Ibrahim A, Lloyd MD. Steady-state kinetic analysis of reversible enzyme inhibitors: A case study on calf intestine alkaline phosphatase. Methods Enzymol 2023; 690:39-84. [PMID: 37858536 DOI: 10.1016/bs.mie.2023.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2023]
Abstract
Enzymes are important drug targets and inhibition of enzymatic activity is an important therapeutic strategy. Enzyme assays measuring catalytic activity are utilized in both the discovery and development of new drugs. Colorimetric assays based on the release of 4-nitrophenol from substrates are commonly used. 4-Nitrophenol is only partly ionized to 4-nitrophenolate under typical assay conditions (pH 7-9) leading to under-estimation of product formation rates due to the much lower extinction coefficient of 4-nitrophenol compared to 4-nitrophenolate. Determination of 4-nitrophenol pKa values based on absorbance at 405 nm as a function of experimental pH values is reported, allowing for calculation of a corrected extinction coefficient at the assay pH. Characterization of inhibitor properties using steady-state enzyme kinetics is demonstrated using calf intestine alkaline phosphatase and 4-nitrophenyl phosphate as substrate at pH ∼8.2. The following kinetic parameters were determined: Km= 40±3 µM; Vmax= 72.8±1.2 µmolmin-1mg protein-1; kcat= 9.70±0.16 s-1; kcat/Km= 2.44±0.16 × 105 M-1s-1 (mean± SEM, N = 4). Sodium orthovanadate and EDTA were used as model inhibitors and the following pIC50 values were measured using dose-response curves: 6.61±0.08 and 3.07±0.03 (mean±SEM, N = 4). Rapid dilution experiments determined that inhibition was reversible for sodium orthovanadate and irreversible for EDTA. A Ki value for orthovanadate of 51±8 nM (mean±SEM, N = 3) was determined. Finally, data analysis and statistical design of experiments are discussed.
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Affiliation(s)
- Henry Brooke
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom
| | - Meghna Ghoshray
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom
| | - Archad Ibrahim
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom
| | - Matthew D Lloyd
- Department of Life Sciences, University of Bath, Claverton Down, Bath, United Kingdom.
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5
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Boronic Acid Transition State Inhibitors as Potent Inactivators of KPC and CTX-M β-Lactamases: Biochemical and Structural Analyses. Antimicrob Agents Chemother 2023; 67:e0093022. [PMID: 36602311 PMCID: PMC9872677 DOI: 10.1128/aac.00930-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Design of novel β-lactamase inhibitors (BLIs) is one of the currently accepted strategies to combat the threat of cephalosporin and carbapenem resistance in Gram-negative bacteria. Boronic acid transition state inhibitors (BATSIs) are competitive, reversible BLIs that offer promise as novel therapeutic agents. In this study, the activities of two α-amido-β-triazolylethaneboronic acid transition state inhibitors (S02030 and MB_076) targeting representative KPC (KPC-2) and CTX-M (CTX-M-96, a CTX-M-15-type extended-spectrum β-lactamase [ESBL]) β-lactamases were evaluated. The 50% inhibitory concentrations (IC50s) for both inhibitors were measured in the nanomolar range (2 to 135 nM). For S02030, the k2/K for CTX-M-96 (24,000 M-1 s-1) was twice the reported value for KPC-2 (12,000 M-1 s-1); for MB_076, the k2/K values ranged from 1,200 M-1 s-1 (KPC-2) to 3,900 M-1 s-1 (CTX-M-96). Crystal structures of KPC-2 with MB_076 (1.38-Å resolution) and S02030 and the in silico models of CTX-M-96 with these two BATSIs show that interaction in the CTX-M-96-S02030 and CTX-M-96-MB_076 complexes were overall equivalent to that observed for the crystallographic structure of KPC-2-S02030 and KPC-2-MB_076. The tetrahedral interaction surrounding the boron atom from S02030 and MB_076 creates a favorable hydrogen bonding network with S70, S130, N132, N170, and S237. However, the changes from W105 in KPC-2 to Y105 in CTX-M-96 and the missing residue R220 in CTX-M-96 alter the arrangement of the inhibitors in the active site of CTX-M-96, partially explaining the difference in kinetic parameters. The novel BATSI scaffolds studied here advance our understanding of structure-activity relationships (SARs) and illustrate the importance of new approaches to β-lactamase inhibitor design.
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6
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Messner K, Vuong B, Tranmer GK. The Boron Advantage: The Evolution and Diversification of Boron’s Applications in Medicinal Chemistry. Pharmaceuticals (Basel) 2022; 15:ph15030264. [PMID: 35337063 PMCID: PMC8948683 DOI: 10.3390/ph15030264] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Revised: 02/10/2022] [Accepted: 02/13/2022] [Indexed: 12/13/2022] Open
Abstract
In this review, the history of boron’s early use in drugs, and the history of the use of boron functional groups in medicinal chemistry applications are discussed. This includes diazaborines, boronic acids, benzoxaboroles, boron clusters, and carboranes. Furthermore, critical developments from these functional groups are highlighted along with recent developments, which exemplify potential prospects. Lastly, the application of boron in the form of a prodrug, softdrug, and as a nanocarrier are discussed to showcase boron’s emergence into new and exciting fields. Overall, we emphasize the evolution of organoboron therapeutic agents as privileged structures in medicinal chemistry and outline the impact that boron has had on drug discovery and development.
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Affiliation(s)
- Katia Messner
- Rady Faculty of Health Science, College of Pharmacy, University of Manitoba, Winnipeg, MB R3E 0T5, Canada; (K.M.); (B.V.)
| | - Billy Vuong
- Rady Faculty of Health Science, College of Pharmacy, University of Manitoba, Winnipeg, MB R3E 0T5, Canada; (K.M.); (B.V.)
| | - Geoffrey K. Tranmer
- Rady Faculty of Health Science, College of Pharmacy, University of Manitoba, Winnipeg, MB R3E 0T5, Canada; (K.M.); (B.V.)
- Department of Chemistry, Faculty of Science, University of Manitoba, Winnipeg, MB R3E 0T5, Canada
- Correspondence:
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7
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Asghari-Sana F, Khoshbakht S, Azarbayjani AF. New approach to treat methicillin resistant Staphylococcus aureus with the application of boric acid. J Drug Deliv Sci Technol 2022. [DOI: 10.1016/j.jddst.2021.103006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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8
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Newman H, Krajnc A, Bellini D, Eyermann CJ, Boyle GA, Paterson NG, McAuley KE, Lesniak R, Gangar M, von Delft F, Brem J, Chibale K, Schofield CJ, Dowson CG. High-Throughput Crystallography Reveals Boron-Containing Inhibitors of a Penicillin-Binding Protein with Di- and Tricovalent Binding Modes. J Med Chem 2021; 64:11379-11394. [PMID: 34337941 PMCID: PMC9282634 DOI: 10.1021/acs.jmedchem.1c00717] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The effectiveness of β-lactam antibiotics is increasingly compromised by β-lactamases. Boron-containing inhibitors are potent serine-β-lactamase inhibitors, but the interactions of boron-based compounds with the penicillin-binding protein (PBP) β-lactam targets have not been extensively studied. We used high-throughput X-ray crystallography to explore reactions of a boron-containing fragment set with the Pseudomonas aeruginosa PBP3 (PaPBP3). Multiple crystal structures reveal that boronic acids react with PBPs to give tricovalently linked complexes bonded to Ser294, Ser349, and Lys484 of PaPBP3; benzoxaboroles react with PaPBP3 via reaction with two nucleophilic serines (Ser294 and Ser349) to give dicovalently linked complexes; and vaborbactam reacts to give a monocovalently linked complex. Modifications of the benzoxaborole scaffold resulted in a moderately potent inhibition of PaPBP3, though no antibacterial activity was observed. Overall, the results further evidence the potential for the development of new classes of boron-based antibiotics, which are not compromised by β-lactamase-driven resistance.
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Affiliation(s)
- Hector Newman
- School
of Life Sciences, University of Warwick, Coventry CV4 7AL, U.K.
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Alen Krajnc
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Dom Bellini
- School
of Life Sciences, University of Warwick, Coventry CV4 7AL, U.K.
| | - Charles J. Eyermann
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Grant A. Boyle
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Neil G. Paterson
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Katherine E. McAuley
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
| | - Robert Lesniak
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Mukesh Gangar
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
| | - Frank von Delft
- Diamond
Light Source Ltd, Harwell Science and Innovation Campus, Didcot OX11 0DE, U.K.
- Structural
Genomics Consortium (SGC), University of
Oxford, Oxford, U.K.
- Department
of Biochemistry, University of Johannesburg, Auckland Park 2006, South Africa
- Research
Complex at Harwell, Harwell
Science and Innovation Campus, Didcot OX11 0FA, U.K.
| | - Jürgen Brem
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
| | - Kelly Chibale
- Drug
Discovery and Development Centre (H3D), University of Cape Town, Rondebosch 7701, South Africa
- South
African Medical Research Council Drug Discovery and Development Research
Unit, Department of Chemistry and Institute of Infectious Disease
and Molecular Medicine, University of Cape
Town, Rondebosch 7701, South Africa
| | - Christopher J. Schofield
- Department
of Chemistry and the Ineos Oxford Institute of Antimicrobial Research, Chemistry Research Laboratory, 12 Mansfield Road, Oxford OX1 3TA, U.K.
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9
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Cheng Q, DeYonker NJ. Acylation and deacylation mechanism and kinetics of penicillin G reaction with Streptomyces R61 DD-peptidase. J Comput Chem 2020; 41:1685-1697. [PMID: 32323874 DOI: 10.1002/jcc.26210] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 02/26/2020] [Accepted: 04/05/2020] [Indexed: 12/20/2022]
Abstract
Two quantum mechanical (QM)-cluster models are built for studying the acylation and deacylation mechanism and kinetics of Streptomyces R61 DD-peptidase with the penicillin G at atomic level detail. DD-peptidases are bacterial enzymes involved in the cross-linking of peptidoglycan to form the cell wall, necessary for bacterial survival. The cross-linking can be inhibited by antibiotic beta-lactam derivatives through acylation, preventing the acyl-enzyme complex from undergoing further deacylation. The deacylation step was predicted to be rate-limiting. Transition state and intermediate structures are found using density functional theory in this study, and thermodynamic and kinetic properties of the proposed mechanism are evaluated. The acyl-enzyme complex is found lying in a deep thermodynamic sink, and deacylation is indeed the severely rate-limiting step, leading to suicide inhibition of the peptidoglycan cross-linking. The usage of QM-cluster models is a promising technique to understand, improve, and design antibiotics to disrupt function of the Streptomyces R61 DD-peptidase.
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Affiliation(s)
- Qianyi Cheng
- Department of Chemistry, University of Memphis, Memphis, Tennessee, USA
| | - Nathan J DeYonker
- Department of Chemistry, University of Memphis, Memphis, Tennessee, USA
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10
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Boronic Acid Transition State Inhibitors Active against KPC and Other Class A β-Lactamases: Structure-Activity Relationships as a Guide to Inhibitor Design. Antimicrob Agents Chemother 2016; 60:1751-9. [PMID: 26729496 DOI: 10.1128/aac.02641-15] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 12/27/2015] [Indexed: 11/20/2022] Open
Abstract
Boronic acid transition state inhibitors (BATSIs) are competitive, reversible β-lactamase inhibitors (BLIs). In this study, a series of BATSIs with selectively modified regions (R1, R2, and amide group) were strategically designed and tested against representative class A β-lactamases of Klebsiella pneumoniae, KPC-2 and SHV-1. Firstly, the R1 group of compounds 1a to 1c and 2a to 2e mimicked the side chain of cephalothin, whereas for compounds 3a to 3c, 4a, and 4b, the thiophene ring was replaced by a phenyl, typical of benzylpenicillin. Secondly, variations in the R2 groups which included substituted aryl side chains (compounds 1a, 1b, 1c, 3a, 3b, and 3c) and triazole groups (compounds 2a to 2e) were chosen to mimic the thiazolidine and dihydrothiazine ring of penicillins and cephalosporins, respectively. Thirdly, the amide backbone of the BATSI, which corresponds to the amide at C-6 or C-7 of β-lactams, was also changed to the following bioisosteric groups: urea (compound 3b), thiourea (compound 3c), and sulfonamide (compounds 4a and 4b). Among the compounds that inhibited KPC-2 and SHV-1 β-lactamases, nine possessed 50% inhibitory concentrations (IC50s) of ≤ 600 nM. The most active compounds contained the thiopheneacetyl group at R1 and for the chiral BATSIs, a carboxy- or hydroxy-substituted aryl group at R2. The most active sulfonamido derivative, compound 4b, lacked an R2 group. Compound 2b (S02030) was the most active, with acylation rates (k2/K) of 1.2 ± 0.2 × 10(4) M(-1) s(-1) for KPC-2 and 4.7 ± 0.6 × 10(3) M(-1) s(-1) for SHV-1, and demonstrated antimicrobial activity against Escherichia coli DH10B carrying blaSHV variants and blaKPC-2 or blaKPC-3 and against clinical strains of Klebsiella pneumoniae and E. coli producing different class A β-lactamase genes. At most, MICs decreased from 16 to 0.5 mg/liter.
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11
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Dzhekieva L, Adediran SA, Pratt RF. Interactions of "bora-penicilloates" with serine β-lactamases and DD-peptidases. Biochemistry 2014; 53:6530-8. [PMID: 25302576 PMCID: PMC4204886 DOI: 10.1021/bi500970f] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Specific
boronic acids are generally powerful tetrahedral intermediate/transition
state analogue inhibitors of serine amidohydrolases. This group of
enzymes includes bacterial β-lactamases and DD-peptidases where
there has been considerable development of boronic acid inhibitors.
This paper describes the synthesis, determination of the inhibitory
activity, and analysis of the results from two α-(2-thiazolidinyl)
boronic acids that are closer analogues of particular tetrahedral
intermediates involved in β-lactamase and DD-peptidase catalysis
than those previously described. One of them, 2-[1-(dihydroxyboranyl)(2-phenylacetamido)methyl]-5,5-dimethyl-1,3-thiazolidine-4-carboxylic
acid, is a direct analogue of the deacylation tetrahedral intermediates
of these enzymes. These compounds are micromolar inhibitors of class
C β-lactamases but, very unexpectedly, not inhibitors of class
A β-lactamases. We rationalize the latter result on the basis
of a new mechanism of boronic acid inhibition of the class A enzymes.
A stable inhibitory complex is not accessible because of the instability
of an intermediate on its pathway of formation. The new boronic acids
also do not inhibit bacterial DD-peptidases (penicillin-binding proteins).
This result strongly supports a central feature of a previously proposed
mechanism of action of β-lactam antibiotics, where deacylation
of β-lactam-derived acyl-enzymes is not possible because of
unfavorable steric interactions.
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Affiliation(s)
- Liudmila Dzhekieva
- Department of Chemistry, Wesleyan University , Lawn Avenue, Middletown, Connecticut 06459, United States
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12
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Penicillin-binding proteins: evergreen drug targets. Curr Opin Pharmacol 2014; 18:112-9. [DOI: 10.1016/j.coph.2014.09.012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2014] [Accepted: 09/12/2014] [Indexed: 02/07/2023]
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13
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Draganov A, Wang D, Wang B. The Future of Boron in Medicinal Chemistry: Therapeutic and Diagnostic Applications. TOPICS IN MEDICINAL CHEMISTRY 2014. [DOI: 10.1007/7355_2014_65] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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14
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Structural analysis of the role of Pseudomonas aeruginosa penicillin-binding protein 5 in β-lactam resistance. Antimicrob Agents Chemother 2013; 57:3137-46. [PMID: 23629710 DOI: 10.1128/aac.00505-13] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Penicillin-binding protein 5 (PBP5) is one of the most abundant PBPs in Pseudomonas aeruginosa. Although its main function is that of a cell wall dd-carboxypeptidase, it possesses sufficient β-lactamase activity to contribute to the ability of P. aeruginosa to resist the antibiotic activity of the β-lactams. The study of these dual activities is important for understanding the mechanisms of antibiotic resistance by P. aeruginosa, an important human pathogen, and to the understanding of the evolution of β-lactamase activity from the PBP enzymes. We purified a soluble version of P. aeruginosa PBP5 (designated Pa sPBP5) by deletion of its C-terminal membrane anchor. Under in vitro conditions, Pa sPBP5 demonstrates both dd-carboxypeptidase and expanded-spectrum β-lactamase activities. Its crystal structure at a 2.05-Å resolution shows features closely resembling those of the class A β-lactamases, including a shortened loop spanning residues 74 to 78 near the active site and with respect to the conformations adopted by two active-site residues, Ser101 and Lys203. These features are absent in the related PBP5 of Escherichia coli. A comparison of the two Pa sPBP5 monomers in the asymmetric unit, together with molecular dynamics simulations, revealed an active-site flexibility that may explain its carbapenemase activity, a function that is absent in the E. coli PBP5 enzyme. Our functional and structural characterizations underscore the versatility of this PBP5 in contributing to the β-lactam resistance of P. aeruginosa while highlighting how broader β-lactamase activity may be encoded in the structural folds shared by the PBP and serine β-lactamase classes.
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15
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Dzhekieva L, Adediran SA, Herman R, Kerff F, Duez C, Charlier P, Sauvage E, Pratt RF. Inhibition of DD-peptidases by a specific trifluoroketone: crystal structure of a complex with the Actinomadura R39 DD-peptidase. Biochemistry 2013; 52:2128-38. [PMID: 23484909 DOI: 10.1021/bi400048s] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Inhibitors of bacterial DD-peptidases represent potential antibiotics. In the search for alternatives to β-lactams, we have investigated a series of compounds designed to generate transition state analogue structures upon reaction with DD-peptidases. The compounds contain a combination of a peptidoglycan-mimetic specificity handle and a warhead capable of delivering a tetrahedral anion to the enzyme active site. The latter includes a boronic acid, two alcohols, an aldehyde, and a trifluoroketone. The compounds were tested against two low-molecular mass class C DD-peptidases. As expected from previous observations, the boronic acid was a potent inhibitor, but rather unexpectedly from precedent, the trifluoroketone [D-α-aminopimelyl(1,1,1-trifluoro-3-amino)butan-2-one] was also very effective. Taking into account competing hydration, we found the trifluoroketone was the strongest inhibitor of the Actinomadura R39 DD-peptidase, with a subnanomolar (free ketone) inhibition constant. A crystal structure of the complex between the trifluoroketone and the R39 enzyme showed that a tetrahedral adduct had indeed formed with the active site serine nucleophile. The trifluoroketone moiety, therefore, should be considered along with boronic acids and phosphonates as a warhead that can be incorporated into new and effective DD-peptidase inhibitors and therefore, perhaps, antibiotics.
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Affiliation(s)
- Liudmila Dzhekieva
- Department of Chemistry, Wesleyan University , Lawn Avenue, Middletown, Connecticut 06459, United States
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16
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Abstract
The synthesis of the bacterial peptidoglycan has been recognized for over 50 years as fertile ground for antibacterial discovery. Initially, empirical screening of natural products for inhibition of bacterial growth detected many chemical classes of antibiotics whose specific mechanisms of action were eventually dissected and defined. Of the nontoxic antibiotics discovered, most were found to be inhibitors of either protein synthesis or cell wall synthesis, which led to more directed screening for inhibitors of these pathways. Directed screening and design programs for cell wall inhibitors have been undertaken since the 1960s. In that time it has become clear that, while certain steps and intermediates have yielded selective inhibitors and are established targets, other potential targets have not yielded inhibitors whose antibacterial activity is proven to be solely due to that inhibition. Why has this search been so problematic? Are the established targets still worth pursuing? This review will attempt to answer these and other questions and evaluate the viability of targets related to peptidoglycan synthesis.
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Affiliation(s)
- Lynn L Silver
- LL Silver Consulting, LLC, Springfield, New Jersey 07081, USA.
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17
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Development of new drugs for an old target: the penicillin binding proteins. Molecules 2012; 17:12478-505. [PMID: 23095893 PMCID: PMC6268044 DOI: 10.3390/molecules171112478] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 10/05/2012] [Accepted: 10/17/2012] [Indexed: 11/16/2022] Open
Abstract
The widespread use of β-lactam antibiotics has led to the worldwide appearance of drug-resistant strains. Bacteria have developed resistance to β-lactams by two main mechanisms: the production of β-lactamases, sometimes accompanied by a decrease of outer membrane permeability, and the production of low-affinity, drug resistant Penicillin Binding Proteins (PBPs). PBPs remain attractive targets for developing new antibiotic agents because they catalyse the last steps of the biosynthesis of peptidoglycan, which is unique to bacteria, and lies outside the cytoplasmic membrane. Here we summarize the “current state of the art” of non-β-lactam inhibitors of PBPs, which have being developed in an attempt to counter the emergence of β-lactam resistance. These molecules are not susceptible to hydrolysis by β-lactamases and thus present a real alternative to β-lactams. We present transition state analogs such as boronic acids, which can covalently bind to the active serine residue in the catalytic site. Molecules containing ring structures different from the β-lactam-ring like lactivicin are able to acylate the active serine residue. High throughput screening methods, in combination with virtual screening methods and structure based design, have allowed the development of new molecules. Some of these novel inhibitors are active against major pathogens, including methicillin-resistant Staphylococcus aureus (MRSA) and thus open avenues new for the discovery of novel antibiotics.
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18
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Fedarovich A, Djordjevic KA, Swanson SM, Peterson YK, Nicholas RA, Davies C. High-throughput screening for novel inhibitors of Neisseria gonorrhoeae penicillin-binding protein 2. PLoS One 2012; 7:e44918. [PMID: 23049763 PMCID: PMC3458020 DOI: 10.1371/journal.pone.0044918] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2012] [Accepted: 08/09/2012] [Indexed: 11/18/2022] Open
Abstract
The increasing prevalence of N. gonorrhoeae strains exhibiting decreased susceptibility to third-generation cephalosporins and the recent isolation of two distinct strains with high-level resistance to cefixime or ceftriaxone heralds the possible demise of β-lactam antibiotics as effective treatments for gonorrhea. To identify new compounds that inhibit penicillin-binding proteins (PBPs), which are proven targets for β-lactam antibiotics, we developed a high-throughput assay that uses fluorescence polarization (FP) to distinguish the fluorescent penicillin, Bocillin-FL, in free or PBP-bound form. This assay was used to screen a 50,000 compound library for potential inhibitors of N. gonorrhoeae PBP 2, and 32 compounds were identified that exhibited >50% inhibition of Bocillin-FL binding to PBP 2. These included a cephalosporin that provided validation of the assay. After elimination of compounds that failed to exhibit concentration-dependent inhibition, the antimicrobial activity of the remaining 24 was tested. Of these, 7 showed antimicrobial activity against susceptible and penicillin- or cephalosporin-resistant strains of N. gonorrhoeae. In molecular docking simulations using the crystal structure of PBP 2, two of these inhibitors docked into the active site of the enzyme and each mediate interactions with the active site serine nucleophile. This study demonstrates the validity of a FP-based assay to find novel inhibitors of PBPs and paves the way for more comprehensive high-throughput screening against highly resistant strains of N. gonorrhoeae. It also provides a set of lead compounds for optimization of anti-gonococcal agents.
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Affiliation(s)
- Alena Fedarovich
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail: (AF); (CD)
| | - Kevin A. Djordjevic
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Shauna M. Swanson
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Yuri K. Peterson
- Department of Pharmaceutical and Biomedical Sciences, Medical University of South Carolina, Charleston, South Carolina, United States of America
| | - Robert A. Nicholas
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Christopher Davies
- Department of Biochemistry & Molecular Biology, Medical University of South Carolina, Charleston, South Carolina, United States of America
- * E-mail: (AF); (CD)
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19
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Smoum R, Rubinstein A, Dembitsky VM, Srebnik M. Boron containing compounds as protease inhibitors. Chem Rev 2012; 112:4156-220. [PMID: 22519511 DOI: 10.1021/cr608202m] [Citation(s) in RCA: 303] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Affiliation(s)
- Reem Smoum
- The School of Pharmacy, Institute for Drug Research, The Hebrew University of Jerusalem, Faculty of Medicine, Jerusalem, Israel.
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20
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Zervosen A, Bouillez A, Herman A, Amoroso A, Joris B, Sauvage E, Charlier P, Luxen A. Synthesis and evaluation of boronic acids as inhibitors of Penicillin Binding Proteins of classes A, B and C. Bioorg Med Chem 2012; 20:3915-24. [PMID: 22579615 DOI: 10.1016/j.bmc.2012.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 04/05/2012] [Accepted: 04/07/2012] [Indexed: 10/28/2022]
Abstract
In response to the widespread use of β-lactam antibiotics bacteria have evolved drug resistance mechanisms that include the production of resistant Penicillin Binding Proteins (PBPs). Boronic acids are potent β-lactamase inhibitors and have been shown to display some specificity for soluble transpeptidases and PBPs, but their potential as inhibitors of the latter enzymes is yet to be widely explored. Recently, a (2,6-dimethoxybenzamido)methylboronic acid was identified as being a potent inhibitor of Actinomadura sp. R39 transpeptidase (IC(50): 1.3 μM). In this work, we synthesized and studied the potential of a number of acylaminomethylboronic acids as inhibitors of PBPs from different classes. Several derivatives inhibited PBPs of classes A, B and C from penicillin sensitive strains. The (2-nitrobenzamido)methylboronic acid was identified as a good inhibitor of a class A PBP (PBP1b from Streptococcus pneumoniae, IC(50) = 26 μM), a class B PBP (PBP2xR6 from Streptococcus pneumoniae, IC(50) = 138 μM) and a class C PBP (R39 from Actinomadura sp., IC(50) = 0.6 μM). This work opens new avenues towards the development of molecules that inhibit PBPs, and eventually display bactericidal effects, on distinct bacterial species.
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Affiliation(s)
- Astrid Zervosen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart-Tilman, B-4000 Liège, Belgium.
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21
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Dzhekieva L, Kumar I, Pratt RF. Inhibition of Bacterial DD-Peptidases (Penicillin-Binding Proteins) in Membranes and in Vivo by Peptidoglycan-Mimetic Boronic Acids. Biochemistry 2012; 51:2804-11. [DOI: 10.1021/bi300148v] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Liudmila Dzhekieva
- Department of Chemistry, Wesleyan University, Lawn Avenue, Middletown, Connecticut 06459,
United
States
| | - Ish Kumar
- School of Natural
Sciences, Fairleigh Dickinson University, Teaneck, New Jersey 07666, United States
| | - R. F. Pratt
- Department of Chemistry, Wesleyan University, Lawn Avenue, Middletown, Connecticut 06459,
United
States
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22
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Putty S, Rai A, Jamindar D, Pagano P, Quinn CL, Mima T, Schweizer HP, Gutheil WG. Characterization of d-boroAla as a novel broad-spectrum antibacterial agent targeting d-Ala-d-Ala ligase. Chem Biol Drug Des 2011; 78:757-63. [PMID: 21827632 DOI: 10.1111/j.1747-0285.2011.01210.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
d-boroAla was previously characterized as an inhibitor of bacterial alanine racemase and d-Ala-d-Ala ligase enzymes (Biochemistry, 28, 1989, 3541). In this study, d-boroAla was identified and characterized as an antibacterial agent. d-boroAla has activity against both Gram-positive and Gram-negative organisms, with minimal inhibitory concentrations down to 8 μg / mL. A structure-function study on the alkyl side chain (NH(2) -CHR-B(OR')(2) ) revealed that d-boroAla is the most effective agent in a series including boroGly, d-boroHomoAla, and d-boroVal. l-boroAla was much less active, and N-acetylation completely abolished activity. An LC-MS / MS assay was used to demonstrate that d-boroAla exerts its antibacterial activity by inhibition of d-Ala-d-Ala ligase. d-boroAla is bactericidal at 1× minimal inhibitory concentration against Staphylococcus aureus and Bacillus subtilis, which each encode one copy of d-Ala-d-Ala ligase, and at 4× minimal inhibitory concentration against Escherichia coli and Salmonella enterica serovar Typhimurium, which each encode two copies of d-Ala-d-Ala ligase. d-boroAla demonstrated a frequency of resistance of 8 × 10(-8) at 4× minimal inhibitory concentration in S. aureus. These results demonstrate that d-boroAla has promising antibacterial activity and could serve as the lead agent in a new class of d-Ala-d-Ala ligase targeted antibacterial agents. This study also demonstrates d-boroAla as a possible probe for d-Ala-d-Ala ligase function.
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Affiliation(s)
- Sandeep Putty
- Division of Pharmaceutical Sciences, University of Missouri, Kansas City, 2464 Charlotte Street, Kansas City, MO 64108, USA
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23
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Contreras-Martel C, Amoroso A, Woon ECY, Zervosen A, Inglis S, Martins A, Verlaine O, Rydzik AM, Job V, Luxen A, Joris B, Schofield CJ, Dessen A. Structure-guided design of cell wall biosynthesis inhibitors that overcome β-lactam resistance in Staphylococcus aureus (MRSA). ACS Chem Biol 2011; 6:943-51. [PMID: 21732689 DOI: 10.1021/cb2001846] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
β-Lactam antibiotics have long been a treatment of choice for bacterial infections since they bind irreversibly to Penicillin-Binding Proteins (PBPs), enzymes that are vital for cell wall biosynthesis. Many pathogens express drug-insensitive PBPs rendering β-lactams ineffective, revealing a need for new types of PBP inhibitors active against resistant strains. We have identified alkyl boronic acids that are active against pathogens including methicillin-resistant S. aureus (MRSA). The crystal structures of PBP1b complexed to 11 different alkyl boronates demonstrate that in vivo efficacy correlates with the mode of inhibitor side chain binding. Staphylococcal membrane analyses reveal that the most potent alkyl boronate targets PBP1, an autolysis system regulator, and PBP2a, a low β-lactam affinity enzyme. This work demonstrates the potential of boronate-based PBP inhibitors for circumventing β-lactam resistance and opens avenues for the development of novel antibiotics that target Gram-positive pathogens.
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Affiliation(s)
| | - Ana Amoroso
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Esther C. Y. Woon
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | - Astrid Zervosen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Steven Inglis
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | | | - Olivier Verlaine
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Anna M. Rydzik
- Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, U.K
| | | | - André Luxen
- Centre de Recherches du Cyclotron, B30, Université de Liège, Sart Tilman, B4000 Liège, Belgium
| | - Bernard Joris
- Centre d'Ingénierie des Protéines, Institut de Chimie, B6a, Université de Liège, Sart Tilman, B4000 Liège, Belgium
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24
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Bobba S, Gutheil WG. Multivariate geometrical analysis of catalytic residues in the penicillin-binding proteins. Int J Biochem Cell Biol 2011; 43:1490-9. [PMID: 21740978 DOI: 10.1016/j.biocel.2011.06.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 05/04/2011] [Accepted: 06/22/2011] [Indexed: 12/11/2022]
Abstract
Penicillin-binding proteins (PBPs) are bacterial enzymes involved in the final stages of cell wall biosynthesis, and are targets of the β-lactam antibiotics. They can be subdivided into essential high-molecular-mass (HMM) and non-essential low-molecular-mass (LMM) PBPs, and further divided into subclasses based on sequence homologies. PBPs can catalyze transpeptidase or hydrolase (carboxypeptidase and endopeptidase) reactions. The PBPs are of interest for their role in bacterial cell wall biosynthesis, and as mechanistically interesting enzymes which can catalyze alternative reaction pathways using the same catalytic machinery. A global catalytic residue comparison seemed likely to provide insight into structure-function correlations within the PBPs. More than 90 PBP structures were aligned, and a number (40) of active site geometrical parameters extracted. This dataset was analyzed using both univariate and multivariate statistical methods. Several interesting relationships were observed. (1) Distribution of the dihedral angle for the SXXK-motif Lys side chain (DA_1) was bimodal, and strongly correlated with HMM/transpeptidase vs LMM/hydrolase classification/activity (P<0.001). This structural feature may therefore be associated with the main functional difference between the HMM and LMM PBPs. (2) The distance between the SXXK-motif Lys-NZ atom and the Lys/His-nitrogen atom of the (K/H)T(S)G-motif was highly conserved, suggesting importance for PBP function, and a possibly conserved role in the catalytic mechanism of the PBPs. (3) Principal components-based cluster analysis revealed several distinct clusters, with the HMM Class A and B, LMM Class C, and LMM Class A K15 PBPs forming one "Main" cluster, and demonstrating a globally similar arrangement of catalytic residues within this group.
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Affiliation(s)
- Sudheer Bobba
- Division of Pharmaceutical Sciences, University of Missouri-Kansas City, Kansas City, MO 64108, United States
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25
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Zervosen A, Herman R, Kerff F, Herman A, Bouillez A, Prati F, Pratt RF, Frère JM, Joris B, Luxen A, Charlier P, Sauvage E. Unexpected Tricovalent Binding Mode of Boronic Acids within the Active Site of a Penicillin-Binding Protein. J Am Chem Soc 2011; 133:10839-48. [DOI: 10.1021/ja200696y] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | | | - Fabio Prati
- Department of Chemistry, University of Modena and Reggio Emilia, via Campi 183, 41125 Modena, Italy
| | - R. F. Pratt
- Department of Chemistry, Wesleyan University, Middletown, Connecticut 06459, United States
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26
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Woon ECY, Zervosen A, Sauvage E, Simmons KJ, Živec M, Inglis SR, Fishwick CWG, Gobec S, Charlier P, Luxen A, Schofield CJ. Structure guided development of potent reversibly binding penicillin binding protein inhibitors. ACS Med Chem Lett 2011; 2:219-23. [PMID: 24900305 DOI: 10.1021/ml100260x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 12/29/2010] [Indexed: 11/28/2022] Open
Abstract
Following from the evaluation of different types of electrophiles, combined modeling and crystallographic analyses are used to generate potent boronic acid based inhibitors of a penicillin binding protein. The results suggest that a structurally informed approach to penicillin binding protein inhibition will be useful for the development of both improved reversibly binding inhibitors, including boronic acids, and acylating inhibitors, such as β-lactams.
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Affiliation(s)
- Esther C. Y. Woon
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | - Astrid Zervosen
- Centre de Recherches du Cyclotron, B30, Universite de Liège, Sart-Tilman, B-4000 Liège, Belgium
| | - Eric Sauvage
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5, B-4000 Liège, Belgium
| | - Katie J. Simmons
- School of Chemistry, University of Leeds, Leeds LS2 9JT, United Kingdom
| | - Matej Živec
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Steven R. Inglis
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
| | | | - Stanislav Gobec
- Faculty of Pharmacy, University of Ljubljana, Aškerčeva 7, 1000 Ljubljana, Slovenia
| | - Paulette Charlier
- Centre d’Ingénierie des Protéines, Université de Liège, Institut de Physique B5, B-4000 Liège, Belgium
| | - André Luxen
- Centre de Recherches du Cyclotron, B30, Universite de Liège, Sart-Tilman, B-4000 Liège, Belgium
| | - Christopher J. Schofield
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford OX1 3TA, United Kingdom
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27
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Molander GA, Hiebel MA. Synthesis of amidomethyltrifluoroborates and their use in cross-coupling reactions. Org Lett 2011; 12:4876-9. [PMID: 20879742 DOI: 10.1021/ol102039c] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Amidomethyltrifluoroborates were successfully synthesized in a one-pot fashion and used in cross-coupling reactions with a wide variety of aryl and heteroaryl chlorides.
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Affiliation(s)
- Gary A Molander
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States.
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28
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Natural and synthetic small boron-containing molecules as potential inhibitors of bacterial and fungal quorum sensing. Chem Rev 2010; 111:209-37. [PMID: 21171664 DOI: 10.1021/cr100093b] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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29
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Inglis SR, Woon ECY, Thompson AL, Schofield CJ. Observations on the deprotection of pinanediol and pinacol boronate esters via fluorinated intermediates. J Org Chem 2010; 75:468-71. [PMID: 20014787 DOI: 10.1021/jo901930v] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methods for the deprotection of pinanediol and pinacol esters of various boronic acids via fluoroborane intermediates were evaluated. Treatment of the boronate esters with potassium hydrogen difluoride normally gives trifluoroborate salts; in the case of alpha-amido alkyl or o-amido phenyl boronate esters, aqueous workup gives difluoroboranes. Procedures for transformation of both trifluoroborates and difluoroboranes to free boronic acids are described.
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Affiliation(s)
- Steven R Inglis
- The Department of Chemistry, Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, United Kingdom
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30
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Trippier PC, McGuigan C. Boronic acids in medicinal chemistry: anticancer, antibacterial and antiviral applications. MEDCHEMCOMM 2010. [DOI: 10.1039/c0md00119h] [Citation(s) in RCA: 218] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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31
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Inglis SR, Zervosen A, Woon ECY, Gerards T, Teller N, Fischer DS, Luxen A, Schofield CJ. Synthesis and evaluation of 3-(dihydroxyboryl)benzoic acids as D,D-carboxypeptidase R39 inhibitors. J Med Chem 2009; 52:6097-106. [PMID: 19731939 DOI: 10.1021/jm9009718] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Penicillin binding proteins (PBPs) catalyze steps in the biosynthesis of bacterial cell walls and are the targets for the beta-lactam antibiotics. Non-beta-lactam based antibiotics that target PBPs are of interest because bacteria have evolved resistance to the beta-lactam antibiotics. Boronic acids have been developed as inhibitors of the mechanistically related serine beta-lactamases and serine proteases; however, they have not been explored extensively as PBP inhibitors. Here we report aromatic boronic acid inhibitors of the D,D-carboxypeptidase R39 from Actinomadura sp. strain. Analogues of an initially identified inhibitor [3-(dihydroxyboryl)benzoic acid 1, IC(50) 400 microM] were prepared via routes involving pinacol boronate esters, which were deprotected via a two-stage procedure involving intermediate trifluorborate salts that were hydrolyzed to provide the free boronic acids. 3-(Dihydroxyboryl)benzoic acid analogues containing an amide substituent in the meta, but not ortho position were up to 17-fold more potent inhibitors of the R39 PBP and displayed some activity against other PBPs. These compounds may be useful for the development of even more potent boronic acid based PBP inhibitors with a broad spectrum of antibacterial activity.
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32
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Morandi S, Morandi F, Caselli E, Shoichet BK, Prati F. Structure-based optimization of cephalothin-analogue boronic acids as beta-lactamase inhibitors. Bioorg Med Chem 2007; 16:1195-205. [PMID: 17997318 DOI: 10.1016/j.bmc.2007.10.075] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2007] [Revised: 10/11/2007] [Accepted: 10/23/2007] [Indexed: 11/25/2022]
Abstract
Boronic acids have proved to be promising selective inhibitors of beta-lactamases, acting as transition state analogues. Starting from a previously described nanomolar inhibitor of AmpC beta-lactamase, three new inhibitors were designed to gain interactions with highly conserved residues, such as Asn343, and to bind more tightly to the enzyme. Among these, one was obtained by stereoselective synthesis and succeeded in placing its anionic group into the carboxylate binding site of the enzyme, as revealed by X-ray crystallography of the complex inhibitor/AmpC. Nevertheless, it failed at improving affinity, when compared to the lead from which it was derived. The origins of this structural and energetic discrepancy are discussed.
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Affiliation(s)
- Stefania Morandi
- Dipartimento di Chimica, Università degli studi di Modena e Reggio Emilia, via Campi 183, 41100 Modena, Italy
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33
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Lai JH, Wu W, Zhou Y, Maw HH, Liu Y, Milo LJ, Poplawski SE, Henry GD, Sudmeier JL, Sanford DG, Bachovchin WW. Synthesis and Characterization of Constrained Peptidomimetic Dipeptidyl Peptidase IV Inhibitors: Amino-Lactam boroAlanines. J Med Chem 2007; 50:2391-8. [PMID: 17458948 DOI: 10.1021/jm061321+] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe here the epimerization-free synthesis and characterization of a new class of conformationally constrained lactam aminoboronic acid inhibitors of dipeptidyl peptidase IV (DPP IV; E.C. 3.4.14.5). These compounds have the advantage that they cannot undergo the pH-dependent cyclization prevalent in most dipeptidyl boronic acids that attenuates their potency at physiological pH. For example, D-3-amino-1-[L-1-boronic-ethyl]-pyrrolidine-2-one (amino-D-lactam-L-boroAla), one of the best lactam inhibitors of DPP IV, is several orders of magnitude less potent than L-Ala-L-boroPro, as measured by Ki values (2.3 nM vs 30 pM, respectively). At physiological pH, however, it is actually more potent than L-Ala-L-boroPro, as measured by IC50 values (4.2 nM vs 1400 nM), owing to the absence of the potency-attenuating cyclization. In an interesting and at first sight surprising reversal of the relationship between stereochemistry and potency observed with the conformationally unrestrained Xaa-boroPro class of inhibitors, the L-L diastereomers of the lactams are orders of magnitude less effective than the D-L lactams. However, this interesting reversal and the unexpected potency of the D-L lactams as DPP IV inhibitors can be understood in structural terms, which is explained and discussed here.
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Affiliation(s)
- Jack H Lai
- Contribution from the Department of Biochemistry, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA
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Malde AK, Khedkar SA, Coutinho EC. Isosteres of peptides: boron analogs as dipolar forms of α-amino acids – a theoretical study. J PHYS ORG CHEM 2007. [DOI: 10.1002/poc.1139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Yoshida T, Lepp Z, Kadota Y, Satoh Y, Itoh K, Chuman H. Comparative analysis of binding energy of chymostatin with human cathepsin A and its homologous proteins by molecular orbital calculation. J Chem Inf Model 2006; 46:2093-103. [PMID: 16995740 DOI: 10.1021/ci060093p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cathepsin A is a mammalian lysosomal enzyme that catalyzes the hydrolysis of the carboxy-terminal amino acids of polypeptides and also regulates beta-galactosidase and neuraminidase-1 activities through the formation of a multienzymic complex in lysosomes. Human cathepsin A (hCathA), yeast carboxypeptidase (CPY), and wheat carboxypeptidase II (CPW) belong to the alpha/beta-hydrolase fold family. They have structurally similar active-site clefts, but there are small differences in the amino acid residues comprising their active sites that might determine the substrate specificity and sensitivity to microbial inhibitors including chymostatin. To examine the selectivity and binding mechanism of chymostatin as to hCathA, CPY, and CPW at the atomic level, we analyzed the interaction energy between chymostatin and each protein quantitatively by semiempirical molecular orbital calculation AM1 with the continuum solvent model. We predicted the electrostatic repulsion between the P3 cyclic arginine residue of the inhibitor and the Arg344 in the S3 active subsite of hCathA. Genetic conversion of Arg344 of the wild-type hCathA to Ile also caused an increase in its sensitivity to chymostatin, which was correlated with the decrease in the interaction energy calculated with the molecular orbital method. The present results suggest that such molecular calculation should be useful for evaluating the interactions between ligands, including inhibitors and homologous enzymes, in their docking models.
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Affiliation(s)
- Tatsusada Yoshida
- Institute of Health Biosciences, The University of Tokushima Graduate School, 1-78 Shomachi, Tokushima 770-8505, Japan
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Macheboeuf P, Contreras-Martel C, Job V, Dideberg O, Dessen A. Penicillin binding proteins: key players in bacterial cell cycle and drug resistance processes. FEMS Microbiol Rev 2006; 30:673-91. [PMID: 16911039 DOI: 10.1111/j.1574-6976.2006.00024.x] [Citation(s) in RCA: 313] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Bacterial cell division and daughter cell formation are complex mechanisms whose details are orchestrated by at least a dozen different proteins. Penicillin-binding proteins (PBPs), membrane-associated macromolecules which play key roles in the cell wall synthesis process, have been exploited for over 70 years as the targets of the highly successful beta-lactam antibiotics. The increasing incidence of beta-lactam resistant microorganisms, coupled to progress made in genomics, genetics and immunofluorescence microscopy techniques, have encouraged the intensive study of PBPs from a variety of bacterial species. In addition, the recent publication of high-resolution structures of PBPs from pathogenic organisms have shed light on the complex intertwining of drug resistance and cell division processes. In this review, we discuss structural, functional and biological features of such enzymes which, albeit having initially been identified several decades ago, are now being aggressively pursued as highly attractive targets for the development of novel antibiotherapies.
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Affiliation(s)
- Pauline Macheboeuf
- Institut de Biologie Structurale Jean-Pierre Ebel (CNRS/CEA/UJF), UMR 5075, Laboratoire des Protéines Membranaires, Grenoble, France
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Lai JH, Liu Y, Wu W, Zhou Y, Maw HH, Bachovchin WW, Bhat KL, Bock CW. Synthesis and Structural Investigation of Internally Coordinated α-Amidoboronic Acids. J Org Chem 2005; 71:512-9. [PMID: 16408958 DOI: 10.1021/jo051757h] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
[structure: see text] Six new N-acyl-boroGly derivatives, along with their N-acyl-boroSar analogues, have been synthesized by modification of conventional procedures. Structural characterization of these alpha-amidoboronic acids was accomplished by extensive use of 11B and 1H NMR spectroscopy. These compounds were prepared to determine the extent of intramolecular B-O dative bond formation within the context of a five-membered (:O=C-N-C-B) ring motif. It is shown that the formation of such dative bonds depends on the nature of the substituents at both the acyl carbon and the nitrogen atoms. Computational evidence from second-order Møller-Plesset perturbation theory is provided in support of these findings.
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Affiliation(s)
- Jack H Lai
- Department of Biochemistry, Tufts University School of Medicine, 136 Harrison Avenue, Boston, Massachusetts 02111, USA
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Sasubilli R, Gutheil WG. General Inverse Solid-Phase Synthesis Method for C-Terminally Modified Peptide Mimetics. ACTA ACUST UNITED AC 2004; 6:911-5. [PMID: 15530118 DOI: 10.1021/cc049912d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peptide mimetics are of considerable interest as bioactive agents and drugs. C-terminally modified peptide mimetics are of particular interest given the synthetic versatility of the carboxyl group and its derivatives. A general approach to C-terminally modified peptide mimetics, based on a urethane attachment strategy and amino acid t-butyl ester-based N-to-C peptide synthesis, is described. This approach is compatible with the reaction conditions generally employed for solution-phase peptide mimetic synthesis. To develop and demonstrate this approach, it was employed for the solid-phase synthesis of peptide trifluoromethyl ketones, peptide boronic acids, and peptide hydroxamic acids. The development of a versatile general approach to C-terminally modified peptides using readily available starting materials provides a basis for the combinatorial and parallel solid-phase synthesis of these peptide mimetic classes for bioactive agent screening and also provides a basis for the further development of solid-phase C-terminal functional group elaboration strategies.
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Affiliation(s)
- Ramakrishna Sasubilli
- Division of Pharmaceutical Sciences, School of Pharmacy, University of Missouri-Kansas City, Kansas City, Missouri 64110, USA
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Abstract
Over the past forty years, efforts to discover antibacterials have yielded a wide variety of chemical structures, almost exclusively natural products, which inhibit many steps in cell wall synthesis. Although screening for new cell wall inhibitors has been continuous during that period, there have been few reports of new drugs. With the advent of genomics, high resolution X-ray crystallography and the recognition of the need for new antibiotics to combat resistant organisms, there has been a resurgence in interest in this validated target area.
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Affiliation(s)
- Lynn L Silver
- Department of Human and Animal Infectious Diseases, Merck & Co., Rahway, NJ 07065, USA.
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Stefanova ME, Tomberg J, Davies C, Nicholas RA, Gutheil WG. Overexpression and enzymatic characterization of Neisseria gonorrhoeae penicillin-binding protein 4. ACTA ACUST UNITED AC 2003; 271:23-32. [PMID: 14686916 DOI: 10.1046/j.1432-1033.2003.03886.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The penicillin-binding proteins (PBPs) are ubiquitous bacterial enzymes involved in cell wall biosynthesis, and are the targets of the beta-lactam antibiotics. The low molecular mass Neisseria gonorrhoeae PBP 4 (NG PBP 4) is the fourth PBP revealed in the gonococcal genome. NG PBP 4 was cloned, overexpressed, purified, and characterized for beta-lactam binding, DD-carboxypeptidase activity, acyl-donor substrate specificity, transpeptidase activity, inhibition by a number of active site directed reagents, and pH profile. NG PBP 4 was efficiently acylated by penicillin (30,000 m-1.s-1). Against a set of five alpha- and epsilon-substituted l-Lys-D-Ala-D-Ala substrates, NG PBP 4 exhibited wide variation in specificity with a preference for N epsilon-acylated substrates, suggesting a possible preference for crosslinked pentapeptide substrates in the cell wall. Substrates with an N epsilon-Cbz group demonstrated pronounced substrate inhibition. NG PBP 4 showed 30-fold higher activity against the depsipeptide Lac-ester substrate than against the analogous peptide substrate, an indication that k2 (acylation) is rate determining for carboxypeptidase activity. No transpeptidase activity was apparent in a model transpeptidase reaction. Among a number of active site-directed agents, N-chlorosuccinimide, elastinal, iodoacetamide, iodoacetic acid, and phenylglyoxal gave substantial inhibition, and methyl boronic acid gave modest inhibition. The pH profile for activity against Ac2-l-Lys-D-Ala-d-Ala (kcat/Km) was bell-shaped, with pKa values at 6.9 and 10.1. Comparison of the enzymatic properties of NG PBP 4 with other DD-carboxypeptidases highlights both similarities and differences within these enzymes, and suggests the possibility of common mechanistic roles for the two highly conserved active site lysines in Class A and C low molecular mass PBPs.
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Affiliation(s)
- Miglena E Stefanova
- Division of Pharmaceutical Sciences, University of Missouri-Kansas City 64110, USA
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