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Cheng D, Zinker BA, Luo Y, Shipkova P, De Oliveira CH, Krishna G, Brown EA, Boehm SL, Tirucherai GS, Gu H, Ma Z, Chu CH, Onorato JM, Kopcho LM, Ammar R, Smith J, Devasthale P, Lawrence RM, Stryker SA, Dierks EA, Azzara AV, Carayannopoulos L, Charles ED, Lentz KA, Gordon DA. MGAT2 inhibitor decreases liver fibrosis and inflammation in murine NASH models and reduces body weight in human adults with obesity. Cell Metab 2022; 34:1732-1748.e5. [PMID: 36323235 DOI: 10.1016/j.cmet.2022.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 06/14/2022] [Accepted: 10/12/2022] [Indexed: 11/07/2022]
Abstract
Monoacylglycerol acyltransferase 2 (MGAT2) is an important enzyme highly expressed in the human small intestine and liver for the regulation of triglyceride absorption and homeostasis. We report that treatment with BMS-963272, a potent and selective MGAT2 inhibitor, decreased inflammation and fibrosis in CDAHFD and STAM, two murine nonalcoholic steatohepatitis (NASH) models. In high-fat-diet-treated cynomolgus monkeys, in contrast to a selective diacylglycerol acyltransferase 1 (DGAT1) inhibitor, BMS-963272 did not cause diarrhea. In a Phase 1 multiple-dose trial of healthy human adults with obesity (NCT04116632), BMS-963272 was safe and well tolerated with no treatment discontinuations due to adverse events. Consistent with the findings in rodent models, BMS-963272 elevated plasma long-chain dicarboxylic acid, indicating robust pharmacodynamic biomarker modulation; increased gut hormones GLP-1 and PYY; and decreased body weight in human subjects. These data suggest MGAT2 inhibition is a promising therapeutic opportunity for NASH, a disease with high unmet medical needs.
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Affiliation(s)
- Dong Cheng
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA.
| | - Bradley A Zinker
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Yi Luo
- Translational Medicine, Bristol Myers Squibb, Lawrenceville, NJ 08543, USA
| | - Petia Shipkova
- Pharmaceutical Candidate Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | | | - Gopal Krishna
- ICF Early Clinical Development, Bristol Myers Squibb, Summit, NJ 07901, USA
| | - Elizabeth A Brown
- Translational Bioinformatics, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Stephanie L Boehm
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | | | - Huidong Gu
- Translational Medicine, Bristol Myers Squibb, Lawrenceville, NJ 08543, USA
| | - Zhengping Ma
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Ching-Hsuen Chu
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Joelle M Onorato
- Pharmaceutical Candidate Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Lisa M Kopcho
- Leads Discovery and Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Ron Ammar
- Translational Bioinformatics, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Julia Smith
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Pratik Devasthale
- Small Molecule Drug Discovery, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - R Michael Lawrence
- Small Molecule Drug Discovery, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Steven A Stryker
- Pharmaceutical Candidate Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Elizabeth A Dierks
- Pharmaceutical Candidate Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - Anthony V Azzara
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | | | - Edgar D Charles
- Global Drug Development, Bristol Myers Squibb, Lawrenceville, NJ 08543, USA
| | - Kimberley A Lentz
- Pharmaceutical Candidate Optimization, Bristol Myers Squibb, Princeton, NJ 08543, USA
| | - David A Gordon
- Departments of Discovery Biology Cardiovascular and Fibrosis, Bristol Myers Squibb, Princeton, NJ 08543, USA
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Malik R, Park PK, Barbieri CM, Blat Y, Sheriff S, Weigelt CA, Kopcho LM, Celiktas M, Ruzanov M, Naglich JG, Price JL, Harner M, Omalley KM, Deng JI, Schmitz W, Li G, Ruan Z, Qin LY, Duke GJ, Rodrigo I, Witmer MR, Harden DG, Demes S, Arey BJ, Soars M, Fink BE, Gavai AV, Vite GD, Voliva CF. Abstract 1140: A novel MTA non-competitive PRMT5 inhibitor. Cancer Res 2021. [DOI: 10.1158/1538-7445.am2021-1140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
The chromosome 9p21 (chr9p21) locus is deleted in almost 10% of all cancer types. This locus includes the CDKN2A gene that encodes the critical tumor suppressors p19-ARF and p16-INK4a. Methylthioadenosine phosphorylase (MTAP), a gene proximal to CDKN2A, is co-deleted in 80%-90% of tumors with CDKN2A deletion. MTAP plays a critical role in the methionine salvage pathway, and the deletion of MTAP results in the accumulation of its substrate methythioadenosine (MTA). Accumulation of MTA partially inhibits the activity of the arginine methyltransferase PRMT5, causing MTAP deficient cancer cells to be more sensitive to the genetic knockdown of PRMT5. In contrast to genetic knockdown, sensitivity to pharmacological inhibition of PRMT5 does not appear to stratify with MTAP status. However, currently known PRMT5 inhibitors all possess SAM competitive or uncompetitive MOIs, which generally require displacement of MTA from the active site for binding. We hypothesize that leveraging the high MTA state induced by MTAP deficiency will require an inhibitor that can bind PRMT5 without disrupting bound MTA. Here we report the discovery of a PRMT5 inhibitor with a novel binding mode that is compatible with MTA binding. While this compound possesses the desired MOI, it shows only modestly increased potency toward MTAP-null cells. Mathematical simulations of different inhibitor mechanisms indicate that the degree of selectivity that can be achieved depends on the difference in MTA levels between MTAP-null and WT cells. Our in vitro data suggest that the elevation in intracellular MTA concentrations that occurs with MTAP deletion is not sufficient to confer significantly increased sensitivity to PRMT5 inhibition. We anticipate that the therapeutic index that can be achieved between MTAP-null tumor cells and PRMT5-sensitive normal tissues will be similarly limited in vivo.
Citation Format: Rohit Malik, Peter K. Park, Christopher M. Barbieri, Yuval Blat, Steven Sheriff, Carolyn A. Weigelt, Lisa M. Kopcho, Muge Celiktas, Max Ruzanov, Joseph G. Naglich, Jennifer L. Price, Mary Harner, Kevin M. Omalley, JIngjing Deng, William Schmitz, Guo Li, Zheming Ruan, Lan-ying Qin, Gerald J. Duke, Iyoncy Rodrigo, Mark R. Witmer, David G. Harden, Shilpa Demes, Brian J. Arey, Matt Soars, Brian E. Fink, Ashvinikumar V. Gavai, Gregory D. Vite, Charles F. Voliva. A novel MTA non-competitive PRMT5 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 1140.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | - Guo Li
- Bristol Myers Squibb, Princeton, NJ
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3
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Xiao HY, Li N, Duan JJW, Jiang B, Lu Z, Ngu K, Tino J, Kopcho LM, Lu H, Chen J, Tebben AJ, Sheriff S, Chang CY, Yanchunas J, Calambur D, Gao M, Shuster DJ, Susulic V, Xie JH, Guarino VR, Wu DR, Gregor KR, Goldstine CB, Hynes J, Macor JE, Salter-Cid L, Burke JR, Shaw PJ, Dhar TGM. Biologic-like In Vivo Efficacy with Small Molecule Inhibitors of TNFα Identified Using Scaffold Hopping and Structure-Based Drug Design Approaches. J Med Chem 2020; 63:15050-15071. [DOI: 10.1021/acs.jmedchem.0c01732] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Hai-Yun Xiao
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Ning Li
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - James J.-W. Duan
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Bin Jiang
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Zhonghui Lu
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Khehyong Ngu
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Joseph Tino
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Lisa M. Kopcho
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Hao Lu
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Jing Chen
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Andrew J. Tebben
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Steven Sheriff
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - ChiehYing Y. Chang
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Joseph Yanchunas
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Deepa Calambur
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Mian Gao
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - David J. Shuster
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Vojkan Susulic
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Jenny H. Xie
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Victor R. Guarino
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Dauh-Rurng Wu
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Kurt R. Gregor
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Christine B. Goldstine
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - John Hynes
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - John E. Macor
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Luisa Salter-Cid
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - James R. Burke
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - Patrick J. Shaw
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
| | - T. G. Murali Dhar
- Research and Early Development, Bristol Myers Squibb, 3551 Lawrenceville Road, Princeton, New Jersey 08540, United States
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Shaw SA, Vokits BP, Dilger AK, Viet A, Clark CG, Abell LM, Locke GA, Duke G, Kopcho LM, Dongre A, Gao J, Krishnakumar A, Jusuf S, Khan J, Spronk SA, Basso MD, Zhao L, Cantor GH, Onorato JM, Wexler RR, Duclos F, Kick EK. Discovery and structure activity relationships of 7-benzyl triazolopyridines as stable, selective, and reversible inhibitors of myeloperoxidase. Bioorg Med Chem 2020; 28:115723. [PMID: 33007547 DOI: 10.1016/j.bmc.2020.115723] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 08/17/2020] [Accepted: 08/18/2020] [Indexed: 01/15/2023]
Abstract
Myeloperoxidase (MPO) is a heme peroxidase found in neutrophils, monocytes and macrophages that efficiently catalyzes the oxidation of endogenous chloride into hypochlorous acid for antimicrobial activity. Chronic MPO activation can lead to indiscriminate protein modification causing tissue damage, and has been associated with chronic inflammatory diseases, atherosclerosis, and acute cardiovascular events. Triazolopyrimidine 5 is a reversible MPO inhibitor; however it suffers from poor stability in acid, and is an irreversible inhibitor of the DNA repair protein methyl guanine methyl transferase (MGMT). Structure-based drug design was employed to discover benzyl triazolopyridines with improved MPO potency, as well as acid stability, no reactivity with MGMT, and selectivity against thyroid peroxidase (TPO). Structure-activity relationships, a crystal structure of the MPO-inhibitor complex, and acute in vivo pharmacodynamic data are described herein.
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Affiliation(s)
- Scott A Shaw
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States.
| | - Benjamin P Vokits
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Andrew K Dilger
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Andrew Viet
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Charles G Clark
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lynn M Abell
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Gregory A Locke
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Gerald Duke
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lisa M Kopcho
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ashok Dongre
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ji Gao
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Arathi Krishnakumar
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Sutjano Jusuf
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Javed Khan
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Steven A Spronk
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Michael D Basso
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Lei Zhao
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Glenn H Cantor
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Joelle M Onorato
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ruth R Wexler
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Franck Duclos
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
| | - Ellen K Kick
- Bristol Myers Squibb Company, P.O. Box 5400, Princeton, NJ 08543-5400, United States
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5
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Meng W, Adam LP, Behnia K, Zhao L, Yang R, Kopcho LM, Locke GA, Taylor DS, Yin X, Wexler RR, Finlay H. Benzothiazole-based compounds as potent endothelial lipase inhibitors. Bioorg Med Chem Lett 2019; 29:126673. [DOI: 10.1016/j.bmcl.2019.126673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Revised: 09/03/2019] [Accepted: 09/04/2019] [Indexed: 10/26/2022]
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Tebben AJ, Ruzanov M, Gao M, Xie D, Kiefer SE, Yan C, Newitt JA, Zhang L, Kim K, Lu H, Kopcho LM, Sheriff S. Crystal structures of apo and inhibitor-bound TGFβR2 kinase domain: insights into TGFβR isoform selectivity. Acta Crystallogr D Struct Biol 2016; 72:658-74. [PMID: 27139629 DOI: 10.1107/s2059798316003624] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 03/01/2016] [Indexed: 11/10/2022]
Abstract
The cytokine TGF-β modulates a number of cellular activities and plays a critical role in development, hemostasis and physiology, as well as in diseases including cancer and fibrosis. TGF-β signals through two transmembrane serine/threonine kinase receptors: TGFβR1 and TGFβR2. Multiple structures of the TGFβR1 kinase domain are known, but the structure of TGFβR2 remains unreported. Wild-type TGFβR2 kinase domain was refractory to crystallization, leading to the design of two mutated constructs: firstly, a TGFβR1 chimeric protein with seven ATP-site residues mutated to their counterparts in TGFβR2, and secondly, a reduction of surface entropy through mutation of six charged residues on the surface of the TGFβR2 kinase domain to alanines. These yielded apo and inhibitor-bound crystals that diffracted to high resolution (<2 Å). Comparison of these structures with those of TGFβR1 reveal shared ligand contacts as well as differences in the ATP-binding sites, suggesting strategies for the design of pan and selective TGFβR inhibitors.
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Affiliation(s)
- Andrew J Tebben
- Molecular Structure and Design, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Maxim Ruzanov
- Molecular Structure and Design, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Mian Gao
- Protein Science, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Dianlin Xie
- Protein Science, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Susan E Kiefer
- Protein Science, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Chunhong Yan
- Protein Science, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - John A Newitt
- Protein Science, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Liping Zhang
- Discovery Chemistry Oncology, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Kyoung Kim
- Discovery Chemistry Oncology, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
| | - Hao Lu
- Mechanistic Biochemistry, Bristol-Myers Squibb R & D, 311 Pennington Rocky Hill Road, Pennington, NJ 08534, USA
| | - Lisa M Kopcho
- Mechanistic Biochemistry, Bristol-Myers Squibb R & D, 311 Pennington Rocky Hill Road, Pennington, NJ 08534, USA
| | - Steven Sheriff
- Molecular Structure and Design, Bristol-Myers Squibb R & D, PO Box 4000, Princeton, NJ 08543-4000, USA
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Onorato JM, Chu CH, Ma Z, Kopcho LM, Chao HJ, Lawrence RM, Cheng D. Cell-based assay of MGAT2-driven diacylglycerol synthesis for profiling inhibitors: use of a stable isotope-labeled substrate and high-resolution LC/MS. J Lipid Res 2015; 56:747-753. [PMID: 25598079 DOI: 10.1194/jlr.d055020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To demonstrate monoacylglycerol acyltransferase 2 (MGAT2)-mediated enzyme activity in a cellular context, cells of the murine secretin tumor cell-1 line of enteroendocrine origin were used to construct human MGAT2-expressing recombinant cell lines. Low throughput and utilization of radiolabeled substrate in a traditional TLC technique were circumvented by development of a high-resolution LC/MS platform. Monitoring incorporation of stable isotope-labeled D31-palmitate into diacylglycerol (DAG) allowed selective tracing of the cellular DAG synthesis activity. This assay format dramatically reduced background interference and increased the sensitivity and the signal window compared with the TLC method. Using this assay, several MGAT2 inhibitors from different chemotypes were characterized. The described cell-based assay adds a new methodology for the development and evaluation of MGAT2 inhibitors for the treatment of obesity and type 2 diabetes.
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Affiliation(s)
- Joelle M Onorato
- Departments of Bioanalytical and Discovery Analytical Science, Bristol-Myers Squibb Company, Princeton, NJ
| | - Ching-Hsuen Chu
- Fibrosis Discovery, Bristol-Myers Squibb Company, Princeton, NJ
| | - Zhengping Ma
- Fibrosis Discovery, Bristol-Myers Squibb Company, Princeton, NJ
| | - Lisa M Kopcho
- Mechanistic Biochemistry, Bristol-Myers Squibb Company, Princeton, NJ
| | - Hannguang J Chao
- Discovery Chemistry, Research and Development, Bristol-Myers Squibb Company, Princeton, NJ
| | - R Michael Lawrence
- Discovery Chemistry, Research and Development, Bristol-Myers Squibb Company, Princeton, NJ
| | - Dong Cheng
- Fibrosis Discovery, Bristol-Myers Squibb Company, Princeton, NJ.
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Marcin LR, Higgins MA, Zusi FC, Zhang Y, Dee MF, Parker MF, Muckelbauer JK, Camac DM, Morin PE, Ramamurthy V, Tebben AJ, Lentz KA, Grace JE, Marcinkeviciene JA, Kopcho LM, Burton CR, Barten DM, Toyn JH, Meredith JE, Albright CF, Bronson JJ, Macor JE, Thompson LA. Synthesis and SAR of indole-and 7-azaindole-1,3-dicarboxamide hydroxyethylamine inhibitors of BACE-1. Bioorg Med Chem Lett 2011; 21:537-41. [DOI: 10.1016/j.bmcl.2010.10.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2010] [Revised: 10/13/2010] [Accepted: 10/15/2010] [Indexed: 11/17/2022]
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Kim YB, Kopcho LM, Kirby MS, Hamann LG, Weigelt CA, Metzler WJ, Marcinkeviciene J. Mechanism of Gly-Pro-pNA cleavage catalyzed by dipeptidyl peptidase-IV and its inhibition by saxagliptin (BMS-477118). Arch Biochem Biophys 2005; 445:9-18. [PMID: 16364232 DOI: 10.1016/j.abb.2005.11.010] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2005] [Revised: 11/17/2005] [Accepted: 11/17/2005] [Indexed: 12/17/2022]
Abstract
Dipeptidyl peptidase-IV (DPP-IV) is a serine protease with a signature Asp-His-Ser motif at the active site. Our pH data suggest that Gly-Pro-pNA cleavage catalyzed by DPP-IV is facilitated by an ionization of a residue with a pK of 7.2 +/- 0.1. By analogy to other serine proteases this pK is suggestive of His-Asp assisted Ser addition to the P1 carbonyl carbon of the substrate to form a tetrahedral intermediate. Solvent kinetic isotope effect studies yielded a D2Okcat/Km=2.9+/-0.2 and a D2Okcat=1.7+/-0.2 suggesting that kinetically significant proton transfers contribute to rate limitation during acyl intermediate formation (leaving group release) and hydrolysis. A "burst" of product release during pre steady-state Gly-Pro-pNA cleavage indicated rate limitation in the deacylation half-reaction. Nevertheless, the amplitude of the burst exceeded the enzyme concentration significantly (approximately 15-fold), which is consistent with a branching deacylation step. All of these data allowed us to better understand DPP-IV inhibition by saxagliptin (BMS-477118). We propose a two-step inhibition mechanism wherein an initial encounter complex is followed by covalent intermediate formation. Final inhibitory complex assembly (kon) depends upon the ionization of an enzyme residue with a pK of 6.2 +/- 0.1, and we assigned it to the catalytic His-Asp pair which enhances Ser nucleophilicity for covalent addition. An ionization with a pK of 7.9 +/- 0.2 likely reflects the P2 terminal amine of the inhibitor hydrogen bonding to Glu205/Glu206 in the enzyme active site. The formation of the covalent enzyme-inhibitor complex was reversible and dissociated with a koff of (5.5 +/- 0.4) x 10(-5) s(-1), thus yielding a Ki* (as koff/kon) of 0.35 nM, which is in good agreement with the value of 0.6 nM obtained from steady-state inhibition studies. Proton NMR spectra of DPP-IV showed a downfield resonance at 16.1 ppm. Two additional peaks in the 1H NMR spectra at 17.4 and 14.1 ppm were observed upon mixing the enzyme with saxagliptin. Fractionation factors (phi) of 0.6 and 0.5 for the 17.4 and 14.1 ppm peaks, respectively, are suggestive of short strong hydrogen bonds in the enzyme-inhibitor complex.
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Affiliation(s)
- Young B Kim
- Department of Chemical Enzymology, Bristol Myers-Squibb Pharmaceutical Company, Pharmaceutical Research Institute, P.O. Box 5400, Princeton, NJ 08543-5400, USA
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Kopcho LM, Kim YB, Wang A, Liu MA, Kirby MS, Marcinkeviciene J. Probing prime substrate binding sites of human dipeptidyl peptidase-IV using competitive substrate approach. Arch Biochem Biophys 2005; 436:367-76. [PMID: 15797249 DOI: 10.1016/j.abb.2005.02.015] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2005] [Revised: 02/08/2005] [Indexed: 10/25/2022]
Abstract
Dipeptidyl peptidase-IV is a cell surface protease which plays an important role in glucose homeostasis through proteolytic inactivation of incretin hormones, primarily glucagon like peptide-1 (GLP-1). Substrate N-terminal amino acid (S2-S1) specificity is rather clearly defined, while no substantial information is available on the significance of amino acid interactions towards the C-terminus after the scissile bond (so called prime S1'-S4' or distant S5'-S28' sites). In the present study the increasing length of the peptide towards prime sites (S1'-S4') resulted in approximately 7-fold decrease in Km. Moreover, the Km for GLP-1 cleavage was comparable to that of an S2-S4' peptide, suggesting that few, if any, important enzyme-substrate interactions occur beyond the active site. Effect of substrate length on kcat was less obvious, but kcat/Km showed an increasing trend when His-Ala-pNA (representing the natural two N-terminal residues) was compared to GLP-1. To probe the impact of increasing substrate length on the free energy of activation (as has been suggested for elastase and chymotrypsin) we performed temperature studies. To adequately interpret thermodynamic data we sought to understand what steps limit the kcat expression. Steady-state parameters of the reactions catalyzed by serine proteases are composed of microscopic constants describing binding, acylation, and deacylation steps. Viscosity and pre-steady-state studies suggested that His-Ala-pNA cleavage is limited in the deacylation half-reaction, most likely the product release step. Thus, the free energy of activation, as calculated from the Eyring equation, is underestimated (at least for His-Ala-pNA) and the effect of substrate length on the acylation step (and transition-state stabilization) could not be unambiguously assessed.
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Affiliation(s)
- Lisa M Kopcho
- Department of Chemical Enzymology, Pharmaceutical Research Institute, Bristol-Myers Squibb Pharmaceutical Company, P.O. Box 5400, Princeton, NJ 08543-5400, USA
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11
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Kopcho LM, Ma J, Marcinkeviciene J, Lai Z, Witmer MR, Cheng J, Yanchunas J, Tredup J, Corbett M, Calambur D, Wittekind M, Paruchuri M, Kothari D, Lee G, Ganguly S, Ramamurthy V, Morin PE, Camac DM, King RW, Lasut AL, Ross OH, Hillman MC, Fish B, Shen K, Dowling RL, Kim YB, Graciani NR, Collins D, Combs AP, George H, Thompson LA, Copeland RA. Comparative studies of active site-ligand interactions among various recombinant constructs of human beta-amyloid precursor protein cleaving enzyme. Arch Biochem Biophys 2003; 410:307-16. [PMID: 12573291 DOI: 10.1016/s0003-9861(02)00690-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Amyloid precursor protein (APP) cleaving enzyme (BACE) is the enzyme responsible for beta-site cleavage of APP, leading to the formation of the amyloid-beta peptide that is thought to be pathogenic in Alzheimer's disease (AD). Hence, BACE is an attractive pharmacological target, and numerous research groups have begun searching for potent and selective inhibitors of this enzyme as a potential mechanism for therapeutic intervention in AD. The mature enzyme is composed of a globular catalytic domain that is N-linked glycosylated in mammalian cells, a single transmembrane helix that anchors the enzyme to an intracellular membrane, and a short C-terminal domain that extends outside the phospholipid bilayer of the membrane. Here we have compared the substrate and active site-directed inhibitor binding properties of several recombinant constructs of human BACE. The constructs studied here address the importance of catalytic domain glycosylation state, inclusion of domains other than the catalytic domain, and incorporation into a membrane bilayer on the interactions of the enzyme active site with peptidic ligands. We find no significant differences in ligand binding properties among these various constructs. These data demonstrate that the nonglycosylated, soluble catalytic domain of BACE faithfully reflects the ligand binding properties of the full-length mature enzyme in its natural membrane environment. Thus, the use of the nonglycosylated, soluble catalytic domain of BACE is appropriate for studies aimed at understanding the determinants of ligand recognition by the enzyme active site.
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Affiliation(s)
- Lisa M Kopcho
- Department of Chemical Enzymology, Hopewell, NJ, USA
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12
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Haque TS, Tadesse S, Marcinkeviciene J, Rogers MJ, Sizemore C, Kopcho LM, Amsler K, Ecret LD, Zhan DL, Hobbs F, Slee A, Trainor GL, Stern AM, Copeland RA, Combs AP. Parallel synthesis of potent, pyrazole-based inhibitors of Helicobacter pylori dihydroorotate dehydrogenase. J Med Chem 2002; 45:4669-78. [PMID: 12361393 DOI: 10.1021/jm020112w] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The identification of several potent pyrazole-based inhibitors of bacterial dihydroorotate dehydrogenase (DHODase) via a directed parallel synthetic approach is described below. The initial pyrazole-containing lead compounds were optimized for potency against Helicobacter pylori DHODase. Using three successive focused libraries, inhibitors were rapidly identified with the following characteristics: K(i) < 10 nM against H. pylori DHODase, sub-microg/mL H. pylori minimum inhibitory concentration activity, low molecular weight, and >10 000-fold selectivity over human DHODase.
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Affiliation(s)
- Tasir S Haque
- Department of Medicinal Chemistry, Bristol-Myers Squibb Company, Experimental Station, Route 141 and Henry Clay Road, Wilmington, Delaware 19880, USA.
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13
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Marcinkeviciene J, Kopcho LM, Yang T, Copeland RA, Glass BM, Combs AP, Falahatpisheh N, Thompson L. Novel inhibition of porcine pepsin by a substituted piperidine. Preference for one of the enzyme conformers. J Biol Chem 2002; 277:28677-82. [PMID: 12029090 DOI: 10.1074/jbc.m203120200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Pepsin inhibition by 3-alkoxy-4-arylpiperidine (substituted piperidine; (3R,4R)-3-(4-bromobenzyloxy)-4-[4-(2-naphthalen-1-yl-2-oxo-ethoxy)phenyl]piperidine) has been studied using steady-state kinetic and pre-equilibrium binding methods. Data were compared with pepstatin A, a well known competitive inhibitor of pepsin. Steady-state analysis reveals that the substituted piperidine likewise behaves as a competitive inhibitor. Pre-equilibrium binding studies indicate that the substituted piperidine can displace a fluorescently labeled statine inhibitor from the enzyme active site. Simulation of the stopped-flow fluorescence transients provided estimates of the K(d) values of 1.4 +/- 0.2 microm and 39 +/- 2 nm for the piperidine and the fluorescently labeled statine, respectively. The effects of combinations of these two inhibitors resulted in a series of parallel lines when plotted by the method of Yonetani and Theorell (Yonetani, T., and Theorell, H. (1964) Arch. Biochem. Biophys. 106, 234-251), suggesting that the two inhibitors bind in a mutually exclusive fashion to pepsin. Fitting of the entire data set to the appropriate equation yielded an alpha factor of 8 +/- 1. The magnitude of this factor ( infinity > alpha > 1) can be explained by a conformational distinction between the enzyme species that bind each inhibitor. The effects of pH on the inhibition constants for pepstatin A and the substituted piperidine also suggest that the inhibitors bind to distinct conformational forms of the enzyme. No inhibition by the piperidine was observed at acidic pH, while pepstatin A inhibition is maximal at low pH values. Inhibition by the piperidine was maximal when a group with pK 4.8 +/- 0.2 was deprotonated and another group with pK 5.9 +/- 0.2 was protonated. Most likely these two groups are the catalytic aspartates with perturbed ionization properties as a result of a significant and unique conformational change. Taken together, these data suggest that the enzyme can readily interconvert between two conformers, one capable of binding substrate and pepstatin A and the other capable of binding the substituted piperidine.
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Affiliation(s)
- Jovita Marcinkeviciene
- Department of Chemical Enzymology, Bristol-Myers Squibb Pharmaceutical Company, Wilmington, Delaware 19880-0400, USA.
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Marcinkeviciene J, Jiang W, Kopcho LM, Locke G, Luo Y, Copeland RA. Enoyl-ACP Reductase (FabI) of Haemophilus influenzae: Steady-State Kinetic Mechanism and Inhibition by Triclosan and Hexachlorophene. Arch Biochem Biophys 2001. [DOI: 10.1006/abbi.2001.2706] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Marcinkeviciene J, Jiang W, Kopcho LM, Locke G, Luo Y, Copeland RA. Enoyl-ACP reductase (FabI) of Haemophilus influenzae: steady-state kinetic mechanism and inhibition by triclosan and hexachlorophene. Arch Biochem Biophys 2001; 390:101-8. [PMID: 11368521 DOI: 10.1006/abbi.2001.2349] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Steady-state kinetics, equilibrium binding, and primary substrate kinetic isotope effect studies revealed that the reduction of crotonyl-CoA by NADH, catalyzed by Haemophilus influenzae enoyl-ACP reductase (FabI), follows a rapid equilibrium random kinetic mechanism with negative interaction among the substrates. Two biphenyl inhibitors, triclosan and hexachlorophene, were studied in the context of the kinetic mechanism. IC(50) values for triclosan in the presence and absence of NAD(+) were 0.1 +/- 0.02 and 2.4 +/- 0.02 microM, respectively, confirming previous observations that the E-NAD(+) complex binds triclosan more tightly than the free enzyme. Preincubation of the enzyme with triclosan and NADH suggested that the E-NADH complex is the active triclosan binding species as well. These results were reinforced by measurement of binding kinetic transients. Intrinsic protein fluorescence changes induced by binding of 20 microM triclosan to E, E-NADH, E-NAD(+), and E-crotonyl-CoA occur at rates of 0.0124 +/- 0.001, 0.0663 +/- 0.002, 0.412 +/- 0.01, and 0.0069 +/- 0.0001 s(-1), respectively. The rate of binding decreased with increasing crotonyl-CoA concentrations in the E-crotonyl-CoA complex, and the extrapolated rate at zero concentration of crotonyl-CoA corresponded to the rate observed for the binding to the free enzyme. This suggests that triclosan and the acyl substrate share a common binding site. Hexachlorophene inhibition, on the other hand, was NAD(+)- and time-independent; and the calculated IC(50) value was 2.5 +/- 0.4 microM. Steady-state inhibition patterns did not allow the mode of inhibition to be unambiguously determined, but binding kinetics suggested that free enzyme, E-NAD(+), and E-crotonyl-CoA have similar affinity for hexachlorophene, since the k(obs)s were in the same range of 20-24 s(-1). When the E-NADH complex was mixed with hexachlorophene ligand, concentration-independent fluorescence quenching at 480 nm was observed, suggesting at least partial competition between NADH and hexachlorophene for the same binding site. Mutual exclusivity studies, together with the above-discussed results, indicate that triclosan and hexachlorophene bind at different sites of H. influenzae FabI.
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Affiliation(s)
- J Marcinkeviciene
- Department of Chemical Enzymology, Dupont Pharmaceutical Company, Wilmington, Delaware 19880-0400, USA.
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Mallender WD, Yager D, Onstead L, Nichols MR, Eckman C, Sambamurti K, Kopcho LM, Marcinkeviciene J, Copeland RA, Rosenberry TL. Characterization of recombinant, soluble beta-secretase from an insect cell expression system. Mol Pharmacol 2001; 59:619-26. [PMID: 11179458 DOI: 10.1124/mol.59.3.619] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The beta-site amyloid precursor protein-cleaving enzyme (BACE) cleaves the amyloid precursor protein to produce the N terminus of the amyloid beta peptide, a major component of the plaques found in the brains of Alzheimer's disease patients. Sequence analysis of BACE indicates that the protein contains the consensus sequences found in most known aspartyl proteases, but otherwise has only modest homology with aspartyl proteases of known three-dimensional structure (i.e., pepsin, renin, or cathepsin D). Because BACE has been shown to be one of the two proteolytic activities responsible for the production of the Abeta peptide, this enzyme is a prime target for the design of therapeutic agents aimed at reducing Abeta for the treatment of Alzheimer's disease. Toward this ultimate goal, we have expressed a recombinant, truncated human BACE in a Drosophila melanogaster S2 cell expression system to generate high levels of secreted BACE protein. The protein was convenient to purify and was enzymatically active and specific for cleaving the beta-secretase site of human APP, as demonstrated with soluble APP as the substrate in novel sandwich enzyme-linked immunosorbent assay and Western blot assays. Further kinetic analysis revealed no catalytic differences between this recombinant, secreted BACE, and brain BACE. Both showed a strong preference for substrates that contained the Swedish mutation, where NL is substituted for KM immediately upstream of the cleavage site, relative to the wild-type sequence, and both showed the same extent of inhibition by a peptide-based inhibitor. The capability to produce large quantities of BACE enzyme will facilitate protein structure determination and inhibitor development efforts that may lead to the evolution of useful Alzheimer's disease treatments.
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Affiliation(s)
- W D Mallender
- Department of Pharmacology, Mayo Foundation for Medical Education and Research, Mayo Clinic Jacksonville, Jacksonville, Florida, USA
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Copeland RA, Marcinkeviciene J, Haque TS, Kopcho LM, Jiang W, Wang K, Ecret LD, Sizemore C, Amsler KA, Foster L, Tadesse S, Combs AP, Stern AM, Trainor GL, Slee A, Rogers MJ, Hobbs F. Helicobacter pylori-selective antibacterials based on inhibition of pyrimidine biosynthesis. J Biol Chem 2000; 275:33373-8. [PMID: 10938275 DOI: 10.1074/jbc.m004451200] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
We report the discovery of a class of pyrazole-based compounds that are potent inhibitors of the dihydroorotate dehydrogenase of Helicobacter pylori but that do not inhibit the cognate enzymes from Gram-positive bacteria or humans. In culture these compounds inhibit the growth of H. pylori selectively, showing no effect on other Gram-negative or Gram-positive bacteria or human cell lines. These compounds represent the first examples of H. pylori-specific antibacterial agents. Cellular activity within this structural class appears to be due to dihydroorotate dehydrogenase inhibition. Minor structural changes that abrogate in vitro inhibition of the enzyme likewise eliminate cellular activity. Furthermore, the minimum inhibitory concentrations of these compounds increase upon addition of orotate to the culture medium in a concentration-dependent manner, consistent with dihydroorotate dehydrogenase inhibition as the mechanism of cellular inhibition. The data presented here suggest that targeted inhibition of de novo pyrimidine biosynthesis may be a valuable mechanism for the development of antimicrobial agents selective for H. pylori.
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Affiliation(s)
- R A Copeland
- Department of Chemical Enzymology, the Department of Chemical and Physical Sciences, and the Antimicrobials Group, DuPont Pharmaceuticals Company, Wilmington, Delaware 19880-0400, USA
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Marcinkeviciene J, Jiang W, Locke G, Kopcho LM, Rogers MJ, Copeland RA. A second dihydroorotate dehydrogenase (Type A) of the human pathogen Enterococcus faecalis: expression, purification, and steady-state kinetic mechanism. Arch Biochem Biophys 2000; 377:178-86. [PMID: 10775458 DOI: 10.1006/abbi.2000.1769] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We report the identification, expression, and characterization of a second Dihydroorotate dehydrogenase (DHODase A) from the human pathogen Enterococcus faecalis. The enzyme consists of a polypeptide chain of 322 amino acids that shares 68% identity with the cognate type A enzyme from the bacterium Lactococcus lactis. E. faecalis DHODase A catalyzed the oxidation of l-dihydroorotate while reducing a number of substrates, including fumarate, coenzyme Q(0), and menadione. The steady-state kinetic mechanism has been determined with menadione as an oxidizing substrate at pH 7.5. Initial velocity and product inhibition data suggest that the enzyme follows a two-site nonclassical ping-pong kinetic mechanism. The absorbance of the active site FMN cofactor is quenched in a concentration-dependent manner by titration with orotate and barbituric acid, two competitive inhibitors with respect to dihydroorotate. In contrast, titration of the enzyme with menadione had no effect on FMN absorbance, consistent with nonoverlapping binding sites for dihyroorotate and menadione, as suggested from the kinetic mechanism. The reductive half-reaction has been shown to be only partially rate limiting, and an attempt to evaluate the slow step in the overall reaction has been made by simulating orotate production under steady-state conditions. Our data indicate that the oxidative half-reaction is a rate-limiting segment, while orotate, most likely, retains significant affinity for the reduced enzyme, as suggested by the product inhibition pattern.
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Affiliation(s)
- J Marcinkeviciene
- Department of Chemical Enzymology, DuPont Pharmaceutical Co., Wilmington, Delaware 19880-0400, USA.
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