1
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Chan AHY, Ho TCS, Fathoni I, Hamid R, Hirsch AKH, Saliba KJ, Leeper FJ. Evaluation of ketoclomazone and its analogues as inhibitors of 1-deoxy-d-xylulose 5-phosphate synthases and other thiamine diphosphate (ThDP)-dependent enzymes. RSC Med Chem 2024; 15:1773-1781. [PMID: 38784473 PMCID: PMC11110791 DOI: 10.1039/d4md00083h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 03/27/2024] [Indexed: 05/25/2024] Open
Abstract
Most pathogenic bacteria, apicomplexan parasites and plants rely on the methylerythritol phosphate (MEP) pathway to obtain precursors of isoprenoids. 1-Deoxy-d-xylulose 5-phosphate synthase (DXPS), a thiamine diphosphate (ThDP)-dependent enzyme, catalyses the first and rate-limiting step of the MEP pathway. Due to its absence in humans, DXPS is considered as an attractive target for the development of anti-infectious agents and herbicides. Ketoclomazone is one of the earliest reported inhibitors of DXPS and antibacterial and herbicidal activities have been documented. This study investigated the activity of ketoclomazone on DXPS from various species, as well as the broader ThDP-dependent enzyme family. To gain further insights into the inhibition, we have prepared analogues of ketoclomazone and evaluated their activity in biochemical and computational studies. Our findings support the potential of ketoclomazone as a selective antibacterial agent.
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Affiliation(s)
- Alex H Y Chan
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Terence C S Ho
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
| | - Imam Fathoni
- Research School of Biology, The Australian National University Canberra ACT 2601 Australia
| | - Rawia Hamid
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Anna K H Hirsch
- Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Kevin J Saliba
- Research School of Biology, The Australian National University Canberra ACT 2601 Australia
| | - Finian J Leeper
- Yusuf Hamied Department of Chemistry, University of Cambridge Lensfield Road Cambridge CB2 1EW UK
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2
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Coco L, Toci EM, Chen PYT, Drennan CL, Freel Meyers CL. Potent Inhibition of E. coli DXP Synthase by a gem-Diaryl Bisubstrate Analog. ACS Infect Dis 2024; 10:1312-1326. [PMID: 38513073 PMCID: PMC11019550 DOI: 10.1021/acsinfecdis.3c00734] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/27/2024] [Accepted: 03/01/2024] [Indexed: 03/23/2024]
Abstract
New antimicrobial strategies are needed to address pathogen resistance to currently used antibiotics. Bacterial central metabolism is a promising target space for the development of agents that selectively target bacterial pathogens. 1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) converts pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) to DXP, which is required for synthesis of essential vitamins and isoprenoids in bacterial pathogens. Thus, DXPS is a promising antimicrobial target. Toward this goal, our lab has demonstrated selective inhibition of Escherichia coli DXPS by alkyl acetylphosphonate (alkylAP)-based bisubstrate analogs that exploit the requirement for ternary complex formation in the DXPS mechanism. Here, we present the first DXPS structure with a bisubstrate analog bound in the active site. Insights gained from this cocrystal structure guided structure-activity relationship studies of the bisubstrate scaffold. A low nanomolar inhibitor (compound 8) bearing a gem-dibenzyl glycine moiety conjugated to the acetylphosphonate pyruvate mimic via a triazole-based linker emerged from this study. Compound 8 was found to exhibit slow, tight-binding inhibition, with contacts to E. coli DXPS residues R99 and R478 demonstrated to be important for this behavior. This work has discovered the most potent DXPS inhibitor to date and highlights a new role of R99 that can be exploited in future inhibitor designs toward the development of a novel class of antimicrobial agents.
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Affiliation(s)
- Lauren
B. Coco
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Eucolona M. Toci
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Percival Yang-Ting Chen
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
| | - Catherine L. Drennan
- Department
of Chemistry, Massachusetts Institute of
Technology, Cambridge, Massachusetts 02139, United States
- Howard
Hughes Medical Institute, Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Caren L. Freel Meyers
- Department
of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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3
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Toci EM, Austin SL, Majumdar A, Woodcock HL, Freel Meyers CL. Disruption of an Active Site Network Leads to Activation of C2α-Lactylthiamin Diphosphate on the Antibacterial Target 1-Deoxy-d-xylulose-5-phosphate Synthase. Biochemistry 2024; 63:671-687. [PMID: 38393327 PMCID: PMC11015862 DOI: 10.1021/acs.biochem.3c00735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2024]
Abstract
The bacterial metabolic enzyme 1-deoxy-d-xylulose-5-phosphate synthase (DXPS) catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde-3-phosphate (d-GAP). DXP is an essential bacteria-specific metabolite that feeds into the biosynthesis of isoprenoids, pyridoxal phosphate (PLP), and ThDP. DXPS catalyzes the activation of pyruvate to give the C2α-lactylThDP (LThDP) adduct that is long-lived on DXPS in a closed state in the absence of the cosubstrate. Binding of d-GAP shifts the DXPS-LThDP complex to an open state which coincides with LThDP decarboxylation. This gated mechanism distinguishes DXPS in ThDP enzymology. How LThDP persists on DXPS in the absence of cosubstrate, while other pyruvate decarboxylases readily activate LThDP for decarboxylation, is a long-standing question in the field. We propose that an active site network functions to prevent LThDP activation on DXPS until the cosubstrate binds. Binding of d-GAP coincides with a conformational shift and disrupts the network causing changes in the active site that promote LThDP activation. Here, we show that the substitution of putative network residues, as well as nearby residues believed to contribute to network charge distribution, predictably affects LThDP reactivity. Substitutions predicted to disrupt the network have the effect to activate LThDP for decarboxylation, resulting in CO2 and acetate production. In contrast, a substitution predicted to strengthen the network fails to activate LThDP and has the effect to shift DXPS toward the closed state. Network-disrupting substitutions near the carboxylate of LThDP also have a pronounced effect to shift DXPS to an open state. These results offer initial insights to explain the long-lived LThDP intermediate and its activation through disruption of an active site network, which is unique to DXPS. These findings have important implications for DXPS function in bacteria and its development as an antibacterial target.
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Affiliation(s)
- Eucolona M Toci
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Steven L Austin
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Ananya Majumdar
- Biomolecular NMR Center, Johns Hopkins University, Baltimore, Maryland 21218, United States
| | - H Lee Woodcock
- Department of Chemistry, University of South Florida, Tampa, Florida 33620, United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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4
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Hamid R, Adam S, Lacour A, Monjas L, Köhnke J, Hirsch AKH. 1-deoxy-D-xylulose-5-phosphate synthase from Pseudomonas aeruginosa and Klebsiella pneumoniae reveals conformational changes upon cofactor binding. J Biol Chem 2023; 299:105152. [PMID: 37567475 PMCID: PMC10504544 DOI: 10.1016/j.jbc.2023.105152] [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: 06/11/2023] [Revised: 08/01/2023] [Accepted: 08/03/2023] [Indexed: 08/13/2023] Open
Abstract
The ESKAPE bacteria are the six highly virulent and antibiotic-resistant pathogens that require the most urgent attention for the development of novel antibiotics. Detailed knowledge of target proteins specific to bacteria is essential to develop novel treatment options. The methylerythritol-phosphate (MEP) pathway, which is absent in humans, represents a potentially valuable target for the development of novel antibiotics. Within the MEP pathway, the enzyme 1-deoxy-D-xylulose-5-phosphate synthase (DXPS) catalyzes a crucial, rate-limiting first step and a branch point in the biosynthesis of the vitamins B1 and B6. We report the high-resolution crystal structures of DXPS from the important ESKAPE pathogens Pseudomonas aeruginosa and Klebsiella pneumoniae in both the co-factor-bound and the apo forms. We demonstrate that the absence of the cofactor thiamine diphosphate results in conformational changes that lead to disordered loops close to the active site that might be important for the design of potent DXPS inhibitors. Collectively, our results provide important structural details that aid in the assessment of DXPS as a potential target in the ongoing efforts to combat antibiotic resistance.
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Affiliation(s)
- Rawia Hamid
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Sebastian Adam
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
| | - Antoine Lacour
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany
| | - Leticia Monjas
- Stratingh Institute for Chemistry, University of Groningen, Groningen, The Netherlands
| | - Jesko Köhnke
- Institute of Food Chemistry, Leibniz University Hannover, Hannover, Germany; School of Chemistry, University of Glasgow, Glasgow, UK
| | - Anna K H Hirsch
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany.
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5
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Di X, Ortega-Alarcon D, Kakumanu R, Iglesias-Fernandez J, Diaz L, Baidoo EEK, Velazquez-Campoy A, Rodríguez-Concepción M, Perez-Gil J. MEP pathway products allosterically promote monomerization of deoxy-D-xylulose-5-phosphate synthase to feedback-regulate their supply. PLANT COMMUNICATIONS 2023; 4:100512. [PMID: 36575800 DOI: 10.1016/j.xplc.2022.100512] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/11/2022] [Accepted: 12/22/2022] [Indexed: 05/11/2023]
Abstract
Isoprenoids are a very large and diverse family of metabolites required by all living organisms. All isoprenoids derive from the double-bond isomers isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP), which are produced by the methylerythritol 4-phosphate (MEP) pathway in bacteria and plant plastids. It has been reported that IPP and DMAPP feedback-regulate the activity of deoxyxylulose 5-phosphate synthase (DXS), a dimeric enzyme that catalyzes the main flux-controlling step of the MEP pathway. Here we provide experimental insights into the underlying mechanism. Isothermal titration calorimetry and dynamic light scattering approaches showed that IPP and DMAPP can allosterically bind to DXS in vitro, causing a size shift. In silico ligand binding site analysis and docking calculations identified a potential allosteric site in the contact region between the two monomers of the active DXS dimer. Modulation of IPP and DMAPP contents in vivo followed by immunoblot analyses confirmed that high IPP/DMAPP levels resulted in monomerization and eventual aggregation of the enzyme in bacterial and plant cells. Loss of the enzymatically active dimeric conformation allows a fast and reversible reduction of DXS activity in response to a sudden increase or decrease in IPP/DMAPP supply, whereas aggregation and subsequent removal of monomers that would otherwise be available for dimerization appears to be a more drastic response in the case of persistent IPP/DMAPP overabundance (e.g., by a blockage in their conversion to downstream isoprenoids). Our results represent an important step toward understanding the regulation of the MEP pathway and rational design of biotechnological endeavors aimed at increasing isoprenoid contents in microbial and plant systems.
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Affiliation(s)
- Xueni Di
- Institute for Plant Molecular and Cell Biology (IBMCP), CSIC-Universitat Politècnica de València, 46022 Valencia, Spain; Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain
| | - David Ortega-Alarcon
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain
| | - Ramu Kakumanu
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | | | - Lucia Diaz
- Nostrum Biodiscovery SL, 08029 Barcelona, Spain
| | - Edward E K Baidoo
- Joint BioEnergy Institute, 5885 Hollis Street, Emeryville, CA 94608, USA; Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Adrian Velazquez-Campoy
- Institute for Biocomputation and Physics of Complex Systems (BIFI), Joint Unit GBsC-CSIC-BIFI, Universidad de Zaragoza, 50009 Zaragoza, Spain; Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, 50009 Zaragoza, Spain; Instituto de Investigación Sanitaria de Aragón (IIS Aragon), 50009 Zaragoza, Spain; Centro de Investigación Biomédica en Red en el Área Temática de Enfermedades Hepáticas y Digestivas (CIBERehd), 28029 Madrid, Spain
| | - Manuel Rodríguez-Concepción
- Institute for Plant Molecular and Cell Biology (IBMCP), CSIC-Universitat Politècnica de València, 46022 Valencia, Spain; Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
| | - Jordi Perez-Gil
- Centre for Research in Agricultural Genomics (CRAG), CSIC-IRTA-UAB-UB, Campus UAB Bellaterra, 08193 Barcelona, Spain.
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6
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Johnston ML, Bonett EM, DeColli AA, Freel Meyers CL. Antibacterial Target DXP Synthase Catalyzes the Cleavage of d-Xylulose 5-Phosphate: a Study of Ketose Phosphate Binding and Ketol Transfer Reaction. Biochemistry 2022; 61:1810-1823. [PMID: 35998648 PMCID: PMC9531112 DOI: 10.1021/acs.biochem.2c00274] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The bacterial enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) in a thiamin diphosphate (ThDP)-dependent manner. In addition to its role in isoprenoid biosynthesis, DXP is required for ThDP and pyridoxal phosphate biosynthesis. Due to its function as a branch-point enzyme and its demonstrated substrate and catalytic promiscuity, we hypothesize that DXPS could be key for bacterial adaptation in the dynamic metabolic landscape during infection. Prior work in the Freel Meyers laboratory has illustrated that DXPS displays relaxed specificity toward donor and acceptor substrates and varies acceptor specificity according to the donor used. We have reported that DXPS forms dihydroxyethyl (DHE)ThDP from ketoacid or aldehyde donor substrates via decarboxylation and deprotonation, respectively. Here, we tested other DHE donors and found that DXPS cleaves d-xylulose 5-phosphate (X5P) at C2-C3, producing DHEThDP through a third mechanism involving d-GAP elimination. We interrogated DXPS-catalyzed reactions using X5P as a donor substrate and illustrated (1) production of a semi-stable enzyme-bound intermediate and (2) O2, H+, and d-erythrose 4-phosphate act as acceptor substrates, highlighting a new transketolase-like activity of DXPS. Furthermore, we examined X5P binding to DXPS and suggest that the d-GAP binding pocket plays a crucial role in X5P binding and turnover. Overall, this study reveals a ketose-cleavage reaction catalyzed by DXPS, highlighting the remarkable flexibility for donor substrate usage by DXPS compared to other C-C bond-forming enzymes.
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Affiliation(s)
- Melanie L. Johnston
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Eucolona M. Bonett
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | | | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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7
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Prajapati S, Rabe von Pappenheim F, Tittmann K. Frontiers in the enzymology of thiamin diphosphate-dependent enzymes. Curr Opin Struct Biol 2022; 76:102441. [PMID: 35988322 DOI: 10.1016/j.sbi.2022.102441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2022] [Revised: 07/07/2022] [Accepted: 07/11/2022] [Indexed: 11/25/2022]
Abstract
Enzymes that use thiamin diphosphate (ThDP), the biologically active derivative of vitamin B1, as a cofactor play important roles in cellular metabolism in all domains of life. The analysis of ThDP enzymes in the past decades have provided a general framework for our understanding of enzyme catalysis of this protein family. In this review, we will discuss recent advances in the field that include the observation of "unusual" reactions and reaction intermediates that highlight the chemical versatility of the thiamin cofactor. Further topics cover the structural basis of cooperativity of ThDP enzymes, novel insights into the mechanism and structure of selected enzymes, and the discovery of "superassemblies" as reported, for example, acetohydroxy acid synthase. Finally, we summarize recent findings in the structural organisation and mode of action of 2-keto acid dehydrogenase multienzyme complexes and discuss future directions of this exciting research field.
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Affiliation(s)
- Sabin Prajapati
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
| | - Fabian Rabe von Pappenheim
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
| | - Kai Tittmann
- Department of Molecular Enzymology, Göttingen Center of Molecular Biosciences, Georg-August University Göttingen, Julia-Lermontowa-Weg 3, D-37077 Göttingen, Germany; Max-Planck-Institute for Multidisciplinary Sciences, Am Fassberg 11, D-37077 Göttingen, Germany.
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8
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Lu Z, Wang B, Qiu Z, Zhang R, Zheng J, Jia Z. YdfD, a Lysis Protein of the Qin Prophage, Is a Specific Inhibitor of the IspG-Catalyzed Step in the MEP Pathway of Escherichia coli. Int J Mol Sci 2022; 23:ijms23031560. [PMID: 35163484 PMCID: PMC8835842 DOI: 10.3390/ijms23031560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/26/2022] [Accepted: 01/27/2022] [Indexed: 11/22/2022] Open
Abstract
Bacterial cryptic prophage (defective prophage) genes are known to drastically influence host physiology, such as causing cell growth arrest or lysis, upon expression. Many phages encode lytic proteins to destroy the cell envelope. As natural antibiotics, only a few lysis target proteins were identified. ydfD is a lytic gene from the Qin cryptic prophage that encodes a 63-amino-acid protein, the ectopic expression of which in Escherichia coli can cause nearly complete cell lysis rapidly. The bacterial 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway is responsible for synthesizing the isoprenoids uniquely required for sustaining bacterial growth. In this study, we provide evidence that YdfD can interact with IspG, a key enzyme involved in the MEP pathway, both in vivo and in vitro. We show that intact YdfD is required for the interaction with IspG to perform its lysis function and that the mRNA levels of ydfD increase significantly under certain stress conditions. Crucially, the cell lysis induced by YdfD can be abolished by the overexpression of ispG or the complementation of the IspG enzyme catalysis product methylerythritol 2,4-cyclodiphosphate. We propose that YdfD from the Qin cryptic prophage inhibits IspG to block the MEP pathway, leading to a compromised cell membrane and cell wall biosynthesis and eventual cell lysis.
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Affiliation(s)
- Zhifang Lu
- College of Chemistry, Beijing Normal University, Beijing 100875, China; (Z.L.); (B.W.); (Z.Q.); (R.Z.)
| | - Biying Wang
- College of Chemistry, Beijing Normal University, Beijing 100875, China; (Z.L.); (B.W.); (Z.Q.); (R.Z.)
| | - Zhiyu Qiu
- College of Chemistry, Beijing Normal University, Beijing 100875, China; (Z.L.); (B.W.); (Z.Q.); (R.Z.)
| | - Ruiling Zhang
- College of Chemistry, Beijing Normal University, Beijing 100875, China; (Z.L.); (B.W.); (Z.Q.); (R.Z.)
| | - Jimin Zheng
- College of Chemistry, Beijing Normal University, Beijing 100875, China; (Z.L.); (B.W.); (Z.Q.); (R.Z.)
- Correspondence: (J.Z.); (Z.J.)
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, ON K7L 3N6, Canada
- Correspondence: (J.Z.); (Z.J.)
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9
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Jumde RP, Guardigni M, Gierse RM, Alhayek A, Zhu D, Hamid Z, Johannsen S, Elgaher WAM, Neusens PJ, Nehls C, Haupenthal J, Reiling N, Hirsch AKH. Hit-optimization using target-directed dynamic combinatorial chemistry: development of inhibitors of the anti-infective target 1-deoxy-d-xylulose-5-phosphate synthase. Chem Sci 2021; 12:7775-7785. [PMID: 34168831 PMCID: PMC8188608 DOI: 10.1039/d1sc00330e] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 04/21/2021] [Indexed: 01/12/2023] Open
Abstract
Target-directed dynamic combinatorial chemistry (tdDCC) enables identification, as well as optimization of ligands for un(der)explored targets such as the anti-infective target 1-deoxy-d-xylulose-5-phosphate synthase (DXPS). We report the use of tdDCC to first identify and subsequently optimize binders/inhibitors of the anti-infective target DXPS. The initial hits were also optimized for their antibacterial activity against E. coli and M. tuberculosis during subsequent tdDCC runs. Using tdDCC, we were able to generate acylhydrazone-based inhibitors of DXPS. The tailored tdDCC runs also provided insights into the structure-activity relationship of this novel class of DXPS inhibitors. The competition tdDCC runs provided important information about the mode of inhibition of acylhydrazone-based inhibitors. This approach holds the potential to expedite the drug-discovery process and should be applicable to a range of biological targets.
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Affiliation(s)
- Ravindra P Jumde
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
| | - Melissa Guardigni
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- D3-PharmaChemistry, Istituto Italiano di Tecnologia Via Morego 30 16163 Genoa Italy
| | - Robin M Gierse
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
- Stratingh Institute for Chemistry, University of Groningen Nijenborgh 7 9747 AG Groningen The Netherlands
| | - Alaa Alhayek
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Di Zhu
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
- Stratingh Institute for Chemistry, University of Groningen Nijenborgh 7 9747 AG Groningen The Netherlands
| | - Zhoor Hamid
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Sandra Johannsen
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Walid A M Elgaher
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
| | - Philipp J Neusens
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
| | - Christian Nehls
- RG Biophysics, Research Center Borstel, Leibniz Lung Center Borstel Germany
| | - Jörg Haupenthal
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
| | - Norbert Reiling
- RG Microbial Interface Biology, Research Center Borstel, Leibniz Lung Center Borstel Germany
- German Center for Infection Research (DZIF), Partner site Hamburg-Lübeck-Borstel-Riems Borstel Germany
| | - Anna K H Hirsch
- Department of Drug Design and Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS) - Helmholtz Centre for Infection Research (HZI) Campus Building E8.1 66123 Saarbrücken Germany
- Department of Pharmacy, Saarland University Campus Building E8.1 66123 Saarbrücken Germany
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10
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Johnston ML, Freel Meyers CL. Revealing Donor Substrate-Dependent Mechanistic Control on DXPS, an Enzyme in Bacterial Central Metabolism. Biochemistry 2021; 60:929-939. [PMID: 33660509 PMCID: PMC8015787 DOI: 10.1021/acs.biochem.1c00019] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Revised: 02/23/2021] [Indexed: 11/28/2022]
Abstract
The thiamin diphosphate-dependent enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the formation of DXP from pyruvate (donor) and d-glyceraldehyde 3-phosphate (d-GAP, acceptor). DXPS is essential in bacteria but absent in human metabolism, highlighting it as a potential antibacterial drug target. The enzyme possesses unique structural and mechanistic features that enable development of selective inhibition strategies and raise interesting questions about DXPS function in bacterial pathogens. DXPS distinguishes itself within the ThDP enzyme class by its exceptionally large active site and random sequential mechanism in DXP formation. In addition, DXPS displays catalytic promiscuity and relaxed acceptor substrate specificity, yet previous studies have suggested a preference for pyruvate as the donor substrate when d-GAP is the acceptor substrate. However, such donor specificity studies are potentially hindered by a lack of knowledge about specific, alternative donor-acceptor pairs. In this study, we exploited the promiscuous oxygenase activity of DXPS to uncover alternative donor substrates for DXPS. Characterization of glycolaldehyde, hydroxypyruvate, and ketobutyrate as donor substrates revealed differences in stabilization of enzyme-bound intermediates and acceptor substrate usage, illustrating the influence of the donor substrate on reaction mechanism and acceptor specificity. In addition, we found that DXPS prevents abortive acetyl-ThDP formation from a DHEThDP carbanion/enamine intermediate, similar to transketolase, supporting the potential physiological relevance of this intermediate on DXPS. Taken together, these results offer clues toward alternative roles for DXPS in bacterial pathogen metabolism.
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Affiliation(s)
- Melanie L. Johnston
- Department of Pharmacology and Molecular Sciences,
Johns Hopkins University School of Medicine, Baltimore,
Maryland 21205, United States
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences,
Johns Hopkins University School of Medicine, Baltimore,
Maryland 21205, United States
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11
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Pramastya H, Song Y, Elfahmi EY, Sukrasno S, Quax WJ. Positioning Bacillus subtilis as terpenoid cell factory. J Appl Microbiol 2020; 130:1839-1856. [PMID: 33098223 PMCID: PMC8247319 DOI: 10.1111/jam.14904] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 09/29/2020] [Accepted: 10/09/2020] [Indexed: 12/16/2022]
Abstract
Increasing demands for bioactive compounds have motivated researchers to employ micro‐organisms to produce complex natural products. Currently, Bacillus subtilis has been attracting lots of attention to be developed into terpenoids cell factories due to its generally recognized safe status and high isoprene precursor biosynthesis capacity by endogenous methylerythritol phosphate (MEP) pathway. In this review, we describe the up‐to‐date knowledge of each enzyme in MEP pathway and the subsequent steps of isomerization and condensation of C5 isoprene precursors. In addition, several representative terpene synthases expressed in B. subtilis and the engineering steps to improve corresponding terpenoids production are systematically discussed. Furthermore, the current available genetic tools are mentioned as along with promising strategies to improve terpenoids in B. subtilis, hoping to inspire future directions in metabolic engineering of B. subtilis for further terpenoid cell factory development.
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Affiliation(s)
- H Pramastya
- University of Groningen, Groningen, The Netherlands.,Pharmaceutical Biology Research Group, School of Pharmacy, Institut Teknologi Bandung, Bandung, Indonesia
| | - Y Song
- University of Groningen, Groningen, The Netherlands
| | - E Y Elfahmi
- Pharmaceutical Biology Research Group, School of Pharmacy, Institut Teknologi Bandung, Bandung, Indonesia
| | - S Sukrasno
- Pharmaceutical Biology Research Group, School of Pharmacy, Institut Teknologi Bandung, Bandung, Indonesia
| | - W J Quax
- University of Groningen, Groningen, The Netherlands
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12
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DeColli AA, Zhang X, Heflin KL, Jordan F, Freel Meyers CL. Active Site Histidines Link Conformational Dynamics with Catalysis on Anti-Infective Target 1-Deoxy-d-xylulose 5-Phosphate Synthase. Biochemistry 2019; 58:4970-4982. [PMID: 31724401 DOI: 10.1021/acs.biochem.9b00878] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The product of 1-deoxy-d-xyluose 5-phosphate (DXP) synthase, DXP, feeds into the bacterial biosynthesis of isoprenoids, thiamin diphosphate (ThDP), and pyridoxal phosphate. DXP is essential for human pathogens but not utilized by humans; thus, DXP synthase is an attractive anti-infective target. The unique ThDP-dependent mechanism and structure of DXP synthase offer ideal opportunities for selective targeting. Upon reaction with pyruvate, DXP synthase uniquely stabilizes the predecarboxylation intermediate, C2α-lactylThDP (LThDP), in a closed conformation. Subsequent binding of d-glyceraldehyde 3-phosphate induces an open conformation that is proposed to destabilize LThDP, triggering decarboxylation. Evidence for the closed and open conformations has been revealed by hydrogen-deuterium exchange mass spectrometry and X-ray crystallography, which indicate that H49 and H299 are involved in conformational dynamics and movement of the fork and spoon motifs away from the active site is important for the closed-to-open transition. Interestingly, H49 and H299 are critical for DXP formation and interact with the predecarboxylation intermediate in the closed conformation. H299 is removed from the active site in the open conformation of the postdecarboxylation state. In this study, we show that substitution at H49 and H299 negatively impacts LThDP formation by shifting the conformational equilibrium of DXP synthase toward an open conformation. We also present a method for monitoring the dynamics of the spoon motif that uncovered a previously undetected role for H49 in coordinating the closed conformation. Overall, our results suggest that H49 and H299 are critical for the closed, predecarboxylation state providing the first direct link between catalysis and conformational dynamics.
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Affiliation(s)
- Alicia A DeColli
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Xu Zhang
- Department of Chemistry , Rutgers University , Newark , New Jersey 07102 , United States
| | - Kathryn L Heflin
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Frank Jordan
- Department of Chemistry , Rutgers University , Newark , New Jersey 07102 , United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
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13
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Liang YF, Liu H, Li H, Gao WY. Determination of the Activity of 1-Deoxy-D-Xylulose 5-Phosphate Synthase by Pre-column Derivatization-HPLC Using 1,2-Diamino-4,5-Methylenedioxybenzene as a Derivatizing Reagent. Protein J 2019; 38:160-166. [PMID: 30707333 DOI: 10.1007/s10930-019-09816-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
α-Ketoacids can be determined by HPLC through pre-column derivatization with 1,2-diamino-4,5-methylenedioxybenzene (DMB) as a derivatizing reagent. Using this method, the specific activity and the steady-state kinetic of 1-deoxy-D-xylulose-5-phosphate synthase (DXS) were measured. Firstly, DXS substrate pyruvate was derivatized with DMB in acidic solution; then the corresponding quinoxalinone was elucidated by LC-ESI-MS and quantified by HPLC-UV. The optimum derivatization conditions were as follows: aqueous medium at pH 1.0, reaction temperature 80 °C, reaction time 60 min, molar ratio of DMB to pyruvate 10:1. The HPLC was run with isocratic elution using the mixture of methanol and water (60:40, v/v) as a mobile phase. The detective limit and the linear correlation range of the method were 0.05 µM and 0.002-1.0 mM (R = 0.994), respectively. The relative standard deviation (RSD) of six determinations was 2.48%. The steady-state kinetic parameters of DXS for pyruvate determined with the method were identical to the reported data. The established method is a practical route for evaluation of DXS activity, especially in the research and development of DXS inhibitors.
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Affiliation(s)
- Yan-Fei Liang
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, 710069, Shaanxi, China
| | - Hui Liu
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, 710069, Shaanxi, China
| | - Heng Li
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, 710069, Shaanxi, China
| | - Wen-Yun Gao
- National Engineering Research Center for Miniaturized Detection Systems and College of Life Sciences, Northwest University, 229 North Taibai Road, Xi'an, 710069, Shaanxi, China.
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14
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Chen PYT, DeColli AA, Freel Meyers CL, Drennan CL. X-ray crystallography-based structural elucidation of enzyme-bound intermediates along the 1-deoxy-d-xylulose 5-phosphate synthase reaction coordinate. J Biol Chem 2019; 294:12405-12414. [PMID: 31239351 PMCID: PMC6699841 DOI: 10.1074/jbc.ra119.009321] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 06/16/2019] [Indexed: 01/07/2023] Open
Abstract
1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) uses thiamine diphosphate (ThDP) to convert pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) into 1-deoxy-d-xylulose 5-phosphate (DXP), an essential bacterial metabolite. DXP is not utilized by humans; hence, DXPS has been an attractive antibacterial target. Here, we investigate DXPS from Deinococcus radiodurans (DrDXPS), showing that it has similar kinetic parameters Kmd-GAP and Kmpyruvate (54 ± 3 and 11 ± 1 μm, respectively) and comparable catalytic activity (kcat = 45 ± 2 min-1) with previously studied bacterial DXPS enzymes and employing it to obtain missing structural data on this enzyme family. In particular, we have determined crystallographic snapshots of DrDXPS in two states along the reaction coordinate: a structure of DrDXPS bound to C2α-phosphonolactylThDP (PLThDP), mimicking the native pre-decarboxylation intermediate C2α-lactylThDP (LThDP), and a native post-decarboxylation state with a bound enamine intermediate. The 1.94-Å-resolution structure of PLThDP-bound DrDXPS delineates how two active-site histidine residues stabilize the LThDP intermediate. Meanwhile, the 2.40-Å-resolution structure of an enamine intermediate-bound DrDXPS reveals how a previously unknown 17-Å conformational change removes one of the two histidine residues from the active site, likely triggering LThDP decarboxylation to form the enamine intermediate. These results provide insight into how the bi-substrate enzyme DXPS limits side reactions by arresting the reaction on the less reactive LThDP intermediate when its cosubstrate is absent. They also offer a molecular basis for previous low-resolution experimental observations that correlate decarboxylation of LThDP with protein conformational changes.
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Affiliation(s)
- Percival Yang-Ting Chen
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
| | - Alicia A. DeColli
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, To whom correspondence may be addressed:
Dept. of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205. Tel.:
410-502-4807; Fax:
410-955-3023; E-mail:
| | - Catherine L. Drennan
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139,Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, A Howard Hughes Medical Institute investigator and a senior fellow of the Bio-inspired Solar Energy Program, Canadian Institute for Advanced Research (CIFAR). To whom correspondence may be addressed:
Depts. of Biology and Chemistry, Massachusetts Institute of Technology, 31 Ames St., Bldg. 68-680, Cambridge, MA 02139. Tel.:
617-253-5622; Fax:
617-258-7847; E-mail:
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15
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Goryanova B, Amyes TL, Richard JP. Role of the Carboxylate in Enzyme-Catalyzed Decarboxylation of Orotidine 5'-Monophosphate: Transition State Stabilization Dominates Over Ground State Destabilization. J Am Chem Soc 2019; 141:13468-13478. [PMID: 31365243 PMCID: PMC6735427 DOI: 10.1021/jacs.9b04823] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
![]()
Kinetic
parameters kex (s–1)
and kex/Kd (M–1 s–1) are reported
for exchange
for deuterium in D2O of the C-6 hydrogen of 5-fluororotidine
5′-monophosphate (FUMP) catalyzed by the Q215A,
Y217F, and Q215A/Y217F variants of yeast orotidine 5′-monophosphate
decarboxylase (ScOMPDC) at pD 8.1, and by the Q215A
variant at pD 7.1–9.3. The pD rate profiles for wildtype ScOMPDC and the Q215A variant are identical, except for
a 2.5 log unit downward displacement in the profile for the Q215A
variant. The Q215A, Y217F and Q215A/Y217F substitutions cause 1.3–2.0
kcal/mol larger increases in the activation barrier for wildtype ScOMPDC-catalyzed deuterium exchange compared with decarboxylation,
because of the stronger apparent side chain interaction with the transition
state for the deuterium exchange reaction. The stabilization of the
transition state for the OMPDC-catalyzed deuterium exchange reaction
of FUMP is ca. 19 kcal/mol smaller than the transition
state for decarboxylation of OMP, and ca. 8 kcal/mol
smaller than for OMPDC-catalyzed deprotonation of FUMP to form the vinyl carbanion intermediate common to OMPDC-catalyzed
reactions OMP/FOMP and UMP/FUMP. We propose
that ScOMPDC shows similar stabilizing interactions
with the common portions of decarboxylation and deprotonation transition
states that lead to formation of this vinyl carbanion intermediate,
and that there is a large ca. (19–8) = 11 kcal/mol stabilization
of the former transition state from interactions with the nascent
CO2 of product. The effects of Q215A and Y217F substitutions
on kcat/Km for decarboxylation of OMP are expressed mainly as
an increase in Km for the reactions catalyzed
by the variant enzymes, while the effects on kex/Kd for deuterium exchange are
expressed mainly as an increase in kex. This shows that the Q215 and Y217 side chains stabilize the Michaelis
complex to OMP for the decarboxylation reaction, compared
with the complex to FUMP for the deuterium exchange reaction.
These results provide strong support for the conclusion that interactions
which stabilize the transition state for ScOMPDC-catalyzed
decarboxylation at a nonpolar enzyme active site dominate over interactions
that destabilize the ground-state Michaelis complex.
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Affiliation(s)
- Bogdana Goryanova
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 , United States
| | - Tina L Amyes
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 , United States
| | - John P Richard
- Department of Chemistry , University at Buffalo, SUNY , Buffalo , New York 14260-3000 , United States
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16
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Bartee D, Sanders S, Phillips PD, Harrison MJ, Koppisch AT, Freel Meyers CL. Enamide Prodrugs of Acetyl Phosphonate Deoxy-d-xylulose-5-phosphate Synthase Inhibitors as Potent Antibacterial Agents. ACS Infect Dis 2019; 5:406-417. [PMID: 30614674 DOI: 10.1021/acsinfecdis.8b00307] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To fight the growing threat of antibiotic resistance, new antibiotics are required that target essential bacterial processes other than protein, DNA/RNA, and cell wall synthesis, which constitute the majority of currently used antibiotics. 1-Deoxy-d-xylulose-5-phosphate (DXP) synthase is a vital enzyme in bacterial central metabolism, feeding into the de novo synthesis of thiamine diphosphate, pyridoxal phosphate, and essential isoprenoid precursors isopentenyl diphosphate and dimethylallyl diphosphate. While potent and selective inhibitors of DXP synthase in vitro activity have been discovered, their antibacterial activity is modest. To improve the antibacterial activity of selective alkyl acetylphosphonate (alkylAP) inhibitors of DXP synthase, we synthesized peptidic enamide prodrugs of alkylAPs inspired by the natural product dehydrophos, a prodrug of methyl acetylphosphonate. This prodrug strategy achieves dramatic increases in activity against Gram-negative pathogens for two alkylAPs, butyl acetylphosphonate and homopropargyl acetylphosphonate, decreasing minimum inhibitory concentrations against Escherichia coli by 33- and nearly 2000-fold, respectively. Antimicrobial studies and LC-MS/MS analysis of alkylAP-treated E. coli establish that the increased potency of prodrugs is due to increased accumulation of alkylAP inhibitors of DXP synthase via transport of the prodrug through the OppA peptide permease and subsequent amide hydrolysis. This work demonstrates the promise of targeting DXP synthase for the development of novel antibacterial agents.
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Affiliation(s)
- David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21205, United States
| | - Sara Sanders
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21205, United States
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, 700 South Osborne Drive, Flagstaff, Arizona 86011, United States
| | - Mackenzie J. Harrison
- Department of Chemistry, Northern Arizona University, 700 South Osborne Drive, Flagstaff, Arizona 86011, United States
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, 700 South Osborne Drive, Flagstaff, Arizona 86011, United States
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21205, United States
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17
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Human 2-Oxoglutarate Dehydrogenase and 2-Oxoadipate Dehydrogenase Both Generate Superoxide/H 2O 2 in a Side Reaction and Each Could Contribute to Oxidative Stress in Mitochondria. Neurochem Res 2019; 44:2325-2335. [PMID: 30847859 DOI: 10.1007/s11064-019-02765-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 02/25/2019] [Accepted: 02/26/2019] [Indexed: 12/30/2022]
Abstract
According to recent findings, the human 2-oxoglutarate dehydrogenase complex (hOGDHc) could be an important source of the reactive oxygen species in the mitochondria and could contribute to mitochondrial abnormalities associated with multiple neurodegenerative diseases, including Alzheimer's disease, Huntington disease, and Parkinson's disease. The human 2-oxoadipate dehydrogenase (hE1a) is a novel protein, which is encoded by the DHTKD1 gene. Both missence and nonsense mutations were identified in the DHTKD1 that lead to alpha-aminoadipic and alpha-oxoadipic aciduria, a metabolic disorder with a wide variety of the neurological abnormalities, and Charcot-Marie-Tooth disease type 2Q, an inherited neurological disorder affecting the peripheral nervous system. Recently, the rare pathogenic mutations in DHTKD1 and an increased H2O2 production were linked to the genetic ethiology of Eosinophilic Esophagitis (EoE), a chronic allergic inflammatory esophageal disorder. In view of the importance of hOGDHc in the tricarboxylic acid cycle (TCA cycle) and hE1a on the L-lysine, L-hydroxylysine and L-tryptophan degradation pathway in mitochondria, and to enhance our current understanding of the mechanism of superoxide/H2O2 generation by hOGDHc, and by human 2-oxoadipate dehydrogenase complex (hOADHc), this review focuses on several novel and unanticipated recent findings in vitro that emerged from the Jordan group's research. Most significantly, the hE1o and hE1a now join the hE3 as being able to generate the superoxide/H2O2 in mitochondria.
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18
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Planas F, McLeish MJ, Himo F. Computational characterization of enzyme-bound thiamin diphosphate reveals a surprisingly stable tricyclic state: implications for catalysis. Beilstein J Org Chem 2019; 15:145-159. [PMID: 30745990 PMCID: PMC6350894 DOI: 10.3762/bjoc.15.15] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/10/2018] [Indexed: 12/05/2022] Open
Abstract
Thiamin diphosphate (ThDP)-dependent enzymes constitute a large class of enzymes that catalyze a diverse range of reactions. Many are involved in stereospecific carbon–carbon bond formation and, consequently, have found increasing interest and utility as chiral catalysts in various biocatalytic applications. All ThDP-catalyzed reactions require the reaction of the ThDP ylide (the activated state of the cofactor) with the substrate. Given that the cofactor can adopt up to seven states on an enzyme, identifying the factors affecting the stability of the pre-reactant states is important for the overall understanding of the kinetics and mechanism of the individual reactions. In this paper we use density functional theory calculations to systematically study the different cofactor states in terms of energies and geometries. Benzoylformate decarboxylase (BFDC), which is a well characterized chiral catalyst, serves as the prototypical ThDP-dependent enzyme. A model of the active site was constructed on the basis of available crystal structures, and the cofactor states were characterized in the presence of three different ligands (crystallographic water, benzoylformate as substrate, and (R)-mandelate as inhibitor). Overall, the calculations reveal that the relative stabilities of the cofactor states are greatly affected by the presence and identity of the bound ligands. A surprising finding is that benzoylformate binding, while favoring ylide formation, provided even greater stabilization to a catalytically inactive tricyclic state. Conversely, the inhibitor binding greatly destabilized the ylide formation. Together, these observations have significant implications for the reaction kinetics of the ThDP-dependent enzymes, and, potentially, for the use of unnatural substrates in such reactions.
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Affiliation(s)
- Ferran Planas
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
| | - Michael J McLeish
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis, Indianapolis IN 46202, USA
| | - Fahmi Himo
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, SE-10691 Stockholm, Sweden
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19
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Two active site arginines are critical determinants of substrate binding and catalysis in MenD: a thiamine-dependent enzyme in menaquinone biosynthesis. Biochem J 2018; 475:3651-3667. [DOI: 10.1042/bcj20180548] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 10/10/2018] [Accepted: 10/17/2018] [Indexed: 11/17/2022]
Abstract
The bacterial enzyme MenD, or 2-succinyl-5-enolpyruvyl-6-hydroxy-3-cyclohexene-1-carboxylate (SEPHCHC) synthase, catalyzes an essential Stetter reaction in menaquinone (vitamin K2) biosynthesis via thiamine diphosphate (ThDP)-bound tetrahedral post-decarboxylation intermediates. The detailed mechanism of this intermediate chemistry, however, is still poorly understood, but of significant interest given that menaquinone is an essential electron transporter in many pathogenic bacteria. Here, we used site-directed mutagenesis, enzyme kinetic assays, and protein crystallography to reveal an active–inactive intermediate equilibrium in MenD catalysis and its modulation by two conserved active site arginine residues. We observed that these conserved residues play a key role in shifting the equilibrium to the active intermediate by orienting the C2-succinyl group of the intermediates through strong ionic hydrogen bonding. We found that when this interaction is moderately weakened by amino acid substitutions, the resulting proteins are catalytically competent with the C2-succinyl group taking either the active or the inactive orientation in the post-decarboxylation intermediate. When this hydrogen-bonding interaction was strongly weakened, the succinyl group was re-oriented by 180° relative to the native intermediate, resulting in the reversal of the stereochemistry at the reaction center that disabled catalysis. Interestingly, this inactive intermediate was formed with a distinct kinetic behavior, likely as a result of a non-native mode of enzyme–substrate interaction. The mechanistic insights gained from these findings improve our understanding of the new ThDP-dependent catalysis. More importantly, the non-native-binding site of the inactive MenD intermediate uncovered here provides a new target for the development of antibiotics.
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20
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Bartee D, Freel Meyers CL. Toward Understanding the Chemistry and Biology of 1-Deoxy-d-xylulose 5-Phosphate (DXP) Synthase: A Unique Antimicrobial Target at the Heart of Bacterial Metabolism. Acc Chem Res 2018; 51:2546-2555. [PMID: 30203647 DOI: 10.1021/acs.accounts.8b00321] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Antibiotics are the cornerstone of modern healthcare. The 20th century discovery of sulfonamides and β-lactam antibiotics altered human society immensely. Simple bacterial infections were no longer a leading cause of morbidity and mortality, and antibiotic prophylaxis greatly reduced the risk of infection from surgery. The current healthcare system requires effective antibiotics to function. However, antibiotic-resistant infections are becoming increasingly prevalent, threatening the emergence of a postantibiotic era. To prevent this public health crisis, antibiotics with novel modes of action are needed. Currently available antibiotics target just a few cellular processes to exert their activity: DNA, RNA, protein, and cell wall biosynthesis. Bacterial central metabolism is underexploited, offering a wealth of potential new targets that can be pursued toward expanding the armamentarium against microbial infections. Discovered in 1997 as the first enzyme in the methylerythritol phosphate (MEP) pathway, 1-deoxy-d-xylulose 5-phosphate (DXP) synthase is a thiamine diphosphate (ThDP)-dependent enzyme that catalyzes the decarboxylative condensation of pyruvate and d-glyceraldehyde 3-phosphate (d-GAP) to form DXP. This five-carbon metabolite feeds into three separate essential pathways for bacterial central metabolism: ThDP synthesis, pyridoxal phosphate (PLP) synthesis, and the MEP pathway for isoprenoid synthesis. While it has long been identified as a target for the development of antimicrobial agents, limited progress has been made toward developing selective inhibitors of the enzyme. This Account highlights advances from our lab over the past decade to understand this important and unique enzyme. Unlike all other known ThDP-dependent enzymes, DXP synthase uses a random-sequential mechanism that requires the formation of a ternary complex prior to decarboxylation of the lactyl-ThDP intermediate. Its large active site accommodates a variety of acceptor substrates, lending itself to a number of alternative activities, such as the production of α-hydroxy ketones, hydroxamates, amides, acetolactate, and peracetate. Knowledge gained from mechanistic and substrate-specificity studies has guided the development of selective inhibitors with antibacterial activity and provides a biochemical foundation toward understanding DXP synthase function in bacterial cells. Although it is a promising drug target, the centrality of DXP synthase in bacterial metabolism imparts specific challenges to assessing antibacterial activity of DXP synthase inhibitors, and the susceptibility of most bacteria to current DXP synthase inhibitors is remarkably culture-medium-dependent. Despite these challenges, the study of DXP synthase is poised to reveal the role of DXP synthase in bacterial metabolic adaptability during infection, ultimately providing a more complete picture of how inhibiting this crucial enzyme can be used to develop novel antibiotics.
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Affiliation(s)
- David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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21
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Bartee D, Freel Meyers CL. Targeting the Unique Mechanism of Bacterial 1-Deoxy-d-xylulose-5-phosphate Synthase. Biochemistry 2018; 57:4349-4356. [PMID: 29944345 DOI: 10.1021/acs.biochem.8b00548] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The bacterial metabolite 1-deoxy-d-xyulose 5-phosphate (DXP) is essential in bacterial central metabolism feeding into isoprenoid, thiamin diphosphate (ThDP), and pyridoxal phosphate de novo biosynthesis. Halting its production through the inhibition of DXP synthase is an attractive strategy for the development of novel antibiotics. Recent work has revealed that DXP synthase utilizes a unique random sequential mechanism that requires formation of a ternary complex among pyruvate-derived C2α-lactylthiamin diphosphate (LThDP), d-glyceraldehyde 3-phosphate (d-GAP), and enzyme, setting it apart from all other known ThDP-dependent enzymes. Herein, we describe the development of bisubstrate inhibitors bearing an acetylphosphonate (AP) pyruvate mimic and a distal negative charge mimicking the phosphoryl group of d-GAP, designed to target the unique form of DXP synthase that binds LThDP and d-GAP in a ternary complex. A d-phenylalanine-derived triazole acetylphosphonate (d-PheTrAP) emerged as the most potent inhibitor in this series, displaying slow, tight-binding inhibition with a Ki* of 90 ± 10 nM, forward ( k1) and reverse ( k2) isomerization rates of 1.1 and 0.14 min-1, respectively, and exquisite selectivity (>15000-fold) for DXP synthase over mammalian pyruvate dehydrogenase. d-PheTrAP is the most potent, selective DXP synthase inhibitor described to date and represents the first inhibitor class designed specifically to exploit the unique E-LThDP-GAP ternary complex in ThDP enzymology.
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Affiliation(s)
- David Bartee
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences , The Johns Hopkins University School of Medicine , Baltimore , Maryland 21205 , United States
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22
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Qin M, Song H, Dai X, Chan C, Chan W, Guo Z. Single‐Turnover Kinetics Reveal a Distinct Mode of Thiamine Diphosphate‐Dependent Catalysis in Vitamin K Biosynthesis. Chembiochem 2018; 19:1514-1522. [DOI: 10.1002/cbic.201800143] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Indexed: 01/09/2023]
Affiliation(s)
- Mingming Qin
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Haigang Song
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Present address: Division of Structural BiologyWellcome Trust Centre of Human GenomicsUniversity of Oxford Roosevelt Drive Oxford OX3 7BN UK
| | - Xin Dai
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Chi‐Kong Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Wan Chan
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
- Environmental Science ProgramThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Zhihong Guo
- Department of ChemistryThe Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
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23
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DeColli AA, Nemeria NS, Majumdar A, Gerfen GJ, Jordan F, Freel Meyers CL. Oxidative decarboxylation of pyruvate by 1-deoxy-d-xyulose 5-phosphate synthase, a central metabolic enzyme in bacteria. J Biol Chem 2018; 293:10857-10869. [PMID: 29784878 DOI: 10.1074/jbc.ra118.001980] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 05/17/2018] [Indexed: 01/06/2023] Open
Abstract
The underexploited antibacterial target 1-deoxy-d-xyluose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate (d-GAP). DXP is an essential intermediate in the biosynthesis of ThDP, pyridoxal phosphate, and isoprenoids in many pathogenic bacteria. DXP synthase catalyzes a distinct mechanism in ThDP decarboxylative enzymology in which the first enzyme-bound pre-decarboxylation intermediate, C2α-lactyl-ThDP (LThDP), is stabilized by DXP synthase in the absence of d-GAP, and d-GAP then induces efficient LThDP decarboxylation. Despite the observed LThDP accumulation and lack of evidence for C2α-carbanion formation in the absence of d-GAP, CO2 is released at appreciable levels under these conditions. Here, seeking to resolve these conflicting observations, we show that DXP synthase catalyzes the oxidative decarboxylation of pyruvate under conditions in which LThDP accumulates. O2-dependent LThDP decarboxylation led to one-electron transfer from the C2α-carbanion/enamine to O2, with intermediate ThDP-enamine radical formation, followed by peracetic acid formation en route to acetate. Thus, LThDP formation and decarboxylation and DXP formation were studied under anaerobic conditions. Our results support a model in which O2-dependent LThDP decarboxylation and peracetic acid formation occur in the absence of d-GAP, decreasing the levels of pyruvate and O2 in solution. The relative pyruvate and O2 concentrations then dictate the extent of LThDP accumulation, and its buildup can be observed when [pyruvate] > [O2]. The finding that O2 acts as a structurally distinct trigger of LThDP decarboxylation supports the hypothesis that a mechanism involving small molecule-dependent LThDP decarboxylation equips DXP synthase for diverse, yet uncharacterized cellular functions.
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Affiliation(s)
| | - Natalia S Nemeria
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
| | - Ananya Majumdar
- Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Gary J Gerfen
- the Department of Physiology and Biophysics, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Frank Jordan
- the Department of Chemistry, Rutgers University, Newark, New Jersey 07102, and
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24
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Sanders S, Bartee D, Harrison MJ, Phillips PD, Koppisch AT, Freel Meyers CL. Growth medium-dependent antimicrobial activity of early stage MEP pathway inhibitors. PLoS One 2018; 13:e0197638. [PMID: 29771999 PMCID: PMC5957436 DOI: 10.1371/journal.pone.0197638] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2018] [Accepted: 05/04/2018] [Indexed: 01/01/2023] Open
Abstract
The in vivo microenvironment of bacterial pathogens is often characterized by nutrient limitation. Consequently, conventional rich in vitro culture conditions used widely to evaluate antibacterial agents are often poorly predictive of in vivo activity, especially for agents targeting metabolic pathways. In one such pathway, the methylerythritol phosphate (MEP) pathway, which is essential for production of isoprenoids in bacterial pathogens, relatively little is known about the influence of growth environment on antibacterial properties of inhibitors targeting enzymes in this pathway. The early steps of the MEP pathway are catalyzed by 1-deoxy-d-xylulose 5-phosphate (DXP) synthase and reductoisomerase (IspC). The in vitro antibacterial efficacy of the DXP synthase inhibitor butylacetylphosphonate (BAP) was recently reported to be strongly dependent upon growth medium, with high potency observed under nutrient limitation and exceedingly weak activity in nutrient-rich conditions. In contrast, the well-known IspC inhibitor fosmidomycin has potent antibacterial activity in nutrient-rich conditions, but to date, its efficacy had not been explored under more relevant nutrient-limited conditions. The goal of this work was to thoroughly characterize the effects of BAP and fosmidomycin on bacterial cells under varied growth conditions. In this work, we show that activities of both inhibitors, alone and in combination, are strongly dependent upon growth medium, with differences in cellular uptake contributing to variance in potency of both agents. Fosmidomycin is dissimilar to BAP in that it displays relatively weaker activity in nutrient-limited compared to nutrient-rich conditions. Interestingly, while it has been generally accepted that fosmidomycin activity depends upon expression of the GlpT transporter, our results indicate for the first time that fosmidomycin can enter cells by an alternative mechanism under nutrient limitation. Finally, we show that the potency and relationship of the BAP-fosmidomycin combination also depends upon the growth medium, revealing a striking loss of BAP-fosmidomycin synergy under nutrient limitation. This change in BAP-fosmidomycin relationship suggests a shift in the metabolic and/or regulatory networks surrounding DXP accompanying the change in growth medium, the understanding of which could significantly impact targeting strategies against this pathway. More generally, our findings emphasize the importance of considering physiologically relevant growth conditions for predicting the antibacterial potential MEP pathway inhibitors and for studies of their intracellular targets.
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Affiliation(s)
- Sara Sanders
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
| | - Mackenzie J. Harrison
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Paul D. Phillips
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Andrew T. Koppisch
- Department of Chemistry, Northern Arizona University, Flagstaff, AZ, United States of America
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD, United States of America
- * E-mail:
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25
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Wang X, Dowd CS. The Methylerythritol Phosphate Pathway: Promising Drug Targets in the Fight against Tuberculosis. ACS Infect Dis 2018; 4:278-290. [PMID: 29390176 DOI: 10.1021/acsinfecdis.7b00176] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Tuberculosis (TB), caused by Mycobacterium tuberculosis (Mtb), is a severe infectious disease in need of new chemotherapies especially for drug-resistant cases. To meet the urgent requirement of new TB drugs with novel modes of action, the TB research community has been validating numerous targets from several biosynthetic pathways. The methylerythritol phosphate (MEP) pathway is utilized by Mtb for the biosynthesis of isopentenyl pyrophosphate (IPP) and its isomer dimethylallyl pyrophosphate (DMAPP), the universal five-carbon building blocks of isoprenoids. While being a common biosynthetic pathway in pathogens, the MEP pathway is completely absent in humans. Due to its unique presence in pathogens as well as the essentiality of the MEP pathway in Mtb, the enzymes in this pathway are promising targets for the development of new drugs against tuberculosis. In this Review, we discuss three enzymes in the MEP pathway: 1-deoxy-d-xylulose-5-phosphate synthase (DXS), 1-deoxy-d-xylulose-5-phosphate reductoisomerase (IspC/DXR), and 2 C-methyl-d-erythritol 2,4-cyclodiphosphate synthase (IspF), which appear to be the most promising antitubercular drug targets. Structural and mechanistic features of these enzymes are reviewed, as well as selected inhibitors that show promise as antitubercular agents.
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Affiliation(s)
- Xu Wang
- Department of Chemistry, George Washington University, 800 22nd Street NW, Washington, D.C. 20052, United States
| | - Cynthia S. Dowd
- Department of Chemistry, George Washington University, 800 22nd Street NW, Washington, D.C. 20052, United States
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26
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Handa S, Dempsey DR, Ramamoorthy D, Cook N, Guida WC, Spradling TJ, White JK, Woodcock HL, Merkler DJ. Mechanistic Studies of 1-Deoxy-D-Xylulose-5-Phosphate Synthase from Deinococcus radiodurans. ACTA ACUST UNITED AC 2018; 4. [PMID: 29552677 PMCID: PMC5851014 DOI: 10.21767/2471-8084.100051] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The non-mevalonate dependent (NMVA) pathway for the biosynthesis of isopentenyl pyrophosphate and dimethylallyl pyrophosphate is the sole source of these terpenoids for the production of isoprenoids in the apicomplexan parasites, in many eubacteria, and in plants. The absence of this pathway in higher organisms has opened a new platform for the development of novel antibiotics and anti-malarials. The enzyme catalyzing the first step of the NMVA pathway is 1-deoxy-D-xylulose-5-phosphate synthase (DXPS). DXPS catalyzes the thiamine pyrophosphate- and Mg (II)-dependent conjugation of pyruvate and D-glyceraldehyde-3-phosphate to form 1-deoxy-D-xylulose-5-phosphate and CO2. The kinetic mechanism of DXPS from Deinococcus radiodurans most consistent with our data is random sequential as shown using a combination of kinetic analysis and product and dead-end inhibition studies. The role of active site amino acids, identified by sequence alignment to other DXPS proteins, was probed by constructing and analyzing the catalytic efficacy of a set of targeted site-directed mutants.
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Affiliation(s)
- Sumit Handa
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Daniel R Dempsey
- Departments of Medicine, Biological Chemistry and Molecular Pharmacology, Harvard Medical School and Brigham and Women's Hospital, Boston, UK
| | | | - Nanci Cook
- Department of Chemistry, University of South Florida, USA
| | - Wayne C Guida
- Department of Chemistry, University of South Florida, USA
| | | | - Justin K White
- Department of Chemistry, University of South Florida, USA
| | - H Lee Woodcock
- Department of Chemistry, University of South Florida, USA
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27
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Conformational dynamics of 1-deoxy-d-xylulose 5-phosphate synthase on ligand binding revealed by H/D exchange MS. Proc Natl Acad Sci U S A 2017; 114:9355-9360. [PMID: 28808005 DOI: 10.1073/pnas.1619981114] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The enzyme 1-deoxy-d-xylulose 5-phosphate synthase (DXPS) is a key enzyme in the methylerythritol 4-phosphate pathway and is a target for the development of antibiotics, herbicides, and antimalarial drugs. DXPS catalyzes the formation of 1-deoxy-d-xylulose 5-phosphate (DXP), a branch point metabolite in isoprenoid biosynthesis, and is also used in the biosynthesis of thiamin (vitamin B1) and pyridoxal (vitamin B6). Previously, we found that DXPS is unique among the superfamily of thiamin diphosphate (ThDP)-dependent enzymes in stabilizing the predecarboxylation intermediate, C2-alpha-lactyl-thiamin diphosphate (LThDP), which has subsequent decarboxylation that is triggered by d-glyceraldehyde 3-phosphate (GAP). Herein, we applied hydrogen-deuterium (H/D) exchange MS (HDX-MS) of full-length Escherichia coli DXPS to provide a snapshot of the conformational dynamics of this enzyme, leading to the following conclusions. (i) The high sequence coverage of DXPS allowed us to monitor structural changes throughout the entire enzyme, including two segments (spanning residues 183-238 and 292-317) not observed by X-ray crystallography. (ii) Three regions of DXPS (spanning residues 42-58, 183-199, and 278-298) near the active center displayed both EX1 (monomolecular) and EX2 (bimolecuar) H/D exchange (HDX) kinetic behavior in both ligand-free and ligand-bound states. All other peptides behaved according to the common EX2 kinetic mechanism. (iii) The observation of conformational changes on DXPS provides support for the role of conformational dynamics in the DXPS mechanism: The closed conformation of DXPS is critical for stabilization of LThDP, whereas addition of GAP converts DXPS to the open conformation that coincides with decarboxylation of LThDP and DXP release.
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28
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Sanders S, Vierling RJ, Bartee D, DeColli AA, Harrison MJ, Aklinski JL, Koppisch AT, Freel Meyers CL. Challenges and Hallmarks of Establishing Alkylacetylphosphonates as Probes of Bacterial 1-Deoxy-d-xylulose 5-Phosphate Synthase. ACS Infect Dis 2017. [PMID: 28636325 DOI: 10.1021/acsinfecdis.6b00168] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
1-Deoxy-d-xylulose 5-phosphate (DXP) synthase catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate and d-glyceraldehyde 3-phosphate. DXP is at a metabolic branch point in bacteria, feeding into the methylerythritol phosphate pathway to indispensable isoprenoids and acting as a precursor for biosynthesis of essential cofactors in central metabolism, pyridoxal phosphate and ThDP, the latter of which is also required for DXP synthase catalysis. DXP synthase follows a unique random sequential mechanism and possesses an unusually large active site. These features have guided the design of sterically demanding alkylacetylphosphonates (alkylAPs) toward the development of selective DXP synthase inhibitors. alkylAPs studied here display selective, low μM inhibitory activity against DXP synthase. They are weak inhibitors of bacterial growth in standard nutrient rich conditions. However, bacteria are significantly sensitized to most alkylAPs in defined minimal growth medium, with minimal inhibitory concentrations (MICs) ranging from low μM to low mM and influenced by alkyl-chain length. The longest analog (C8) displays the weakest antimicrobial activity and is a substrate for efflux via AcrAB-TolC. The dependence of inhibitor potency on growth environment emphasizes the need for antimicrobial screening conditions that are relevant to the in vivo microbial microenvironment during infection. DXP synthase expression and thiamin supplementation studies offer support for DXP synthase as an intracellular target for some alkylAPs and reveal both the challenges and intriguing aspects of these approaches to study target engagement.
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Affiliation(s)
- Sara Sanders
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Ryan J. Vierling
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - David Bartee
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Alicia A. DeColli
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
| | - Mackenzie J. Harrison
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Joseph L. Aklinski
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Andrew T. Koppisch
- Department
of Chemistry, Northern Arizona University, Flagstaff, Arizona 86011, United States
| | - Caren L. Freel Meyers
- Department of Pharmacology
and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, United States
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29
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White JK, Handa S, Vankayala SL, Merkler DJ, Woodcock HL. Thiamin Diphosphate Activation in 1-Deoxy-d-xylulose 5-Phosphate Synthase: Insights into the Mechanism and Underlying Intermolecular Interactions. J Phys Chem B 2016; 120:9922-34. [PMID: 27537621 PMCID: PMC5379999 DOI: 10.1021/acs.jpcb.6b07248] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
1-Deoxy-d-xylulose 5-phosphate synthase (DXS) is a thiamin diphosphate (TDP) dependent enzyme that marks the beginning of the methylerythritol 4-phosphate isoprenoid biosynthesis pathway. The mechanism of action for DXS is still poorly understood and begins with the formation of a thiazolium ylide. This TDP activation step is thought to proceed through an intramolecular deprotonation by the 4'-aminopyrimidine ring of TDP; however, this step would occur only after an initial deprotonation of its own 4'-amino group. The mechanism of the initial deprotonation has been hypothesized, by analogy to transketolases, to occur via a histidine or an active site water molecule. Results from hybrid quantum mechanical/molecular mechanical (QM/MM) reaction path calculations reveal an ∼10 kcal/mol difference in transition state energies, favoring a water mediated mechanism over direct deprotonation by histidine. This difference was determined to be largely governed by electrostatic changes induced by conformational variations in the active site. Additionally, mutagenesis studies reveal DXS to be an evolutionarily resilient enzyme. Particularly, we hypothesize that residues H82 and H304 may act in a compensatory fashion if the other is lost due to mutation. Further, nucleus-independent chemical shifts (NICSs) and aromatic stabilization energy (ASE) calculations suggest that reduction in TDP aromaticity also serves as a factor for regulating ylide formation and controlling reactivity.
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Affiliation(s)
- Justin K. White
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - Sumit Handa
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093-0332, United States
| | - Sai Lakshmana Vankayala
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - David J. Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
| | - H. Lee Woodcock
- Department of Chemistry, University of South Florida, 4202 E. Fowler Avenue, CHE205, Tampa, Florida 33620-5250, United States
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30
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Banerjee A, Preiser AL, Sharkey TD. Engineering of Recombinant Poplar Deoxy-D-Xylulose-5-Phosphate Synthase (PtDXS) by Site-Directed Mutagenesis Improves Its Activity. PLoS One 2016; 11:e0161534. [PMID: 27548482 PMCID: PMC4993486 DOI: 10.1371/journal.pone.0161534] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/08/2016] [Indexed: 12/28/2022] Open
Abstract
Deoxyxylulose 5-phosphate synthase (DXS), a thiamine diphosphate (ThDP) dependent enzyme, plays a regulatory role in the methylerythritol 4-phosphate (MEP) pathway. Isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), the end products of this pathway, inhibit DXS by competing with ThDP. Feedback inhibition of DXS by IDP and DMADP constitutes a significant metabolic regulation of this pathway. The aim of this work was to experimentally test the effect of key residues of recombinant poplar DXS (PtDXS) in binding both ThDP and IDP. This work also described the engineering of PtDXS to improve the enzymatic activity by reducing its inhibition by IDP and DMADP. We have designed and tested modifications of PtDXS in an attempt to reduce inhibition by IDP. This could possibly be valuable by removing a feedback that limits the usefulness of the MEP pathway in biotechnological applications. Both ThDP and IDP use similar interactions for binding at the active site of the enzyme, however, ThDP being a larger molecule has more anchoring sites at the active site of the enzyme as compared to the inhibitors. A predicted enzyme structure was examined to find ligand-enzyme interactions, which are relatively more important for inhibitor-enzyme binding than ThDP-enzyme binding, followed by their modifications so that the binding of the inhibitors can be selectively affected compared to ThDP. Two alanine residues important for binding ThDP and the inhibitors were mutated to glycine. In two of the cases, both the IDP inhibition and the overall activity were increased. In another case, both the IDP inhibition and the overall activity were reduced. This provides proof of concept that it is possible to reduce the feedback from IDP on DXS activity.
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Affiliation(s)
- Aparajita Banerjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States of America
| | - Alyssa L. Preiser
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States of America
| | - Thomas D. Sharkey
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States of America
- * E-mail:
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31
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Nemeria NS, Shome B, DeColli AA, Heflin K, Begley TP, Meyers CF, Jordan F. Competence of Thiamin Diphosphate-Dependent Enzymes with 2'-Methoxythiamin Diphosphate Derived from Bacimethrin, a Naturally Occurring Thiamin Anti-vitamin. Biochemistry 2016; 55:1135-48. [PMID: 26813608 PMCID: PMC4852132 DOI: 10.1021/acs.biochem.5b01300] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Bacimethrin (4-amino-5-hydroxymethyl-2-methoxypyrimidine), a natural product isolated from some bacteria, has been implicated as an inhibitor of bacterial and yeast growth, as well as in inhibition of thiamin biosynthesis. Given that thiamin biosynthetic enzymes could convert bacimethrin to 2'-methoxythiamin diphosphate (MeOThDP), it is important to evaluate the effect of this coenzyme analogue on thiamin diphosphate (ThDP)-dependent enzymes. The potential functions of MeOThDP were explored on five ThDP-dependent enzymes: the human and Escherichia coli pyruvate dehydrogenase complexes (PDHc-h and PDHc-ec, respectively), the E. coli 1-deoxy-D-xylulose 5-phosphate synthase (DXPS), and the human and E. coli 2-oxoglutarate dehydrogenase complexes (OGDHc-h and OGDHc-ec, respectively). Using several mechanistic tools (fluorescence, circular dichroism, kinetics, and mass spectrometry), it was demonstrated that MeOThDP binds in the active centers of ThDP-dependent enzymes, however, with a binding mode different from that of ThDP. While modest activities resulted from addition of MeOThDP to E. coli PDHc (6-11%) and DXPS (9-14%), suggesting that MeOThDP-derived covalent intermediates are converted to the corresponding products (albeit with rates slower than that with ThDP), remarkably strong activity (up to 75%) resulted upon addition of the coenzyme analogue to PDHc-h. With PDHc-ec and PDHc-h, the coenzyme analogue could support all reactions, including communication between components in the complex. No functional substitution of MeOThDP for ThDP was in evidence with either OGDH-h or OGDH-ec, shown to be due to tight binding of ThDP.
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Affiliation(s)
- Natalia S. Nemeria
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States
| | - Brateen Shome
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Alicia A. DeColli
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Kathryn Heflin
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Tadhg P. Begley
- Department of Chemistry, Texas A&M University, College Station, Texas 77842, United States
| | - Caren Freel Meyers
- Department of Pharmacology and Molecular Sciences, Johns Hopkins School of Medicine, Baltimore, Maryland 21205, United States
| | - Frank Jordan
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102, United States
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32
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Battistini MR, Shoji C, Handa S, Breydo L, Merkler DJ. Mechanistic binding insights for 1-deoxy-D-Xylulose-5-Phosphate synthase, the enzyme catalyzing the first reaction of isoprenoid biosynthesis in the malaria-causing protists, Plasmodium falciparum and Plasmodium vivax. Protein Expr Purif 2015; 120:16-27. [PMID: 26699947 DOI: 10.1016/j.pep.2015.12.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 12/04/2015] [Accepted: 12/09/2015] [Indexed: 11/30/2022]
Abstract
We have successfully truncated and recombinantly-expressed 1-deoxy-D-xylulose-5-phosphate synthase (DXS) from both Plasmodium vivax and Plasmodium falciparum. We elucidated the order of substrate binding for both of these ThDP-dependent enzymes using steady-state kinetic analyses, dead-end inhibition, and intrinsic tryptophan fluorescence titrations. Both enzymes adhere to a random sequential mechanism with respect to binding of both substrates: pyruvate and D-glyceraldehyde-3-phosphate. These findings are in contrast to other ThDP-dependent enzymes, which exhibit classical ordered and/or ping-pong kinetic mechanisms. A better understanding of the kinetic mechanism for these two Plasmodial enzymes could aid in the development of novel DXS-specific inhibitors that might prove useful in treatment of malaria.
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Affiliation(s)
- Matthew R Battistini
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Christopher Shoji
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA
| | - Sumit Handa
- Department of Chemistry and Biochemistry, University of California San Diego, 9500 Gilman Dr., La Jolla, CA 92093, USA
| | - Leonid Breydo
- College of Medicine and Molecular Medicine, University of South Florida Health, 12901 Bruce B. Downs Blvd., MDC 3529, Tampa, FL 33612, USA
| | - David J Merkler
- Department of Chemistry, University of South Florida, 4202 E. Fowler Ave., Tampa, FL 33620, USA.
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Tong Y, Su P, Zhao Y, Zhang M, Wang X, Liu Y, Zhang X, Gao W, Huang L. Molecular Cloning and Characterization of DXS and DXR Genes in the Terpenoid Biosynthetic Pathway of Tripterygium wilfordii. Int J Mol Sci 2015; 16:25516-35. [PMID: 26512659 PMCID: PMC4632813 DOI: 10.3390/ijms161025516] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 10/08/2015] [Accepted: 10/13/2015] [Indexed: 11/18/2022] Open
Abstract
1-Deoxy-d-xylulose-5-phosphate synthase (DXS) and 1-deoxy-d-xylulose-5-phosphate reductoisomerase (DXR) genes are the key enzyme genes of terpenoid biosynthesis but still unknown in Tripterygium wilfordii Hook. f. Here, three full-length cDNA encoding DXS1, DXS2 and DXR were cloned from suspension cells of T. wilfordii with ORF sizes of 2154 bp (TwDXS1, GenBank accession no.KM879187), 2148 bp (TwDXS2, GenBank accession no.KM879186), 1410 bp (TwDXR, GenBank accession no.KM879185). And, the TwDXS1, TwDXS2 and TwDXR were characterized by color complementation in lycopene accumulating strains of Escherichia coli, which indicated that they encoded functional proteins and promoted lycopene pathway flux. TwDXS1 and TwDXS2 are constitutively expressed in the roots, stems and leaves and the expression level showed an order of roots > stems > leaves. After the suspension cells were induced by methyl jasmonate, the mRNA expression level of TwDXS1, TwDXS2, and TwDXR increased, and triptophenolide was rapidly accumulated to 149.52 µg·g−1, a 5.88-fold increase compared with the control. So the TwDXS1, TwDXS2, and TwDXR could be important genes involved in terpenoid biosynthesis in Tripterygium wilfordii Hook. f.
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Affiliation(s)
- Yuru Tong
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Ping Su
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Yujun Zhao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Meng Zhang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Xiujuan Wang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Yujia Liu
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Xianan Zhang
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Wei Gao
- School of Traditional Chinese Medicine, Capital Medical University, Beijing 100069, China.
| | - Luqi Huang
- National Resource Center for Chinese Materia Medica, China Academy of Chinese Medical Sciences, Beijing 100700, China.
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34
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Li H, Ma D, Jin Y, Tu Y, Liu L, Leng C, Dong J, Wang T. Helper component-proteinase enhances the activity of 1-deoxy-D-xylulose-5-phosphate synthase and promotes the biosynthesis of plastidic isoprenoids in Potato virus Y-infected tobacco. PLANT, CELL & ENVIRONMENT 2015; 38:2023-34. [PMID: 25736930 DOI: 10.1111/pce.12526] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Accepted: 02/20/2015] [Indexed: 06/04/2023]
Abstract
Virus-infected plants show strong morphological and physiological alterations. Many physiological processes in chloroplast are affected, including the plastidic isoprenoid biosynthetic pathway [the 2C-methyl-D-erythritol-4-phosphate (MEP) pathway]; indeed, isoprenoid contents have been demonstrated to be altered in virus-infected plants. In this study, we found that the levels of photosynthetic pigments and abscisic acid (ABA) were altered in Potato virus Y (PVY)-infected tobacco. Using yeast two-hybrid assays, we demonstrated an interaction between virus protein PVY helper component-proteinase (HC-Pro) and tobacco chloroplast protein 1-deoxy-D-xylulose-5-phosphate synthase (NtDXS). This interaction was confirmed using bimolecular fluorescence complementation (BiFC) assays and pull-down assays. The Transket_pyr domain (residues 394-561) of NtDXS was required for interaction with HC-Pro, while the N-terminal region of HC-Pro (residues 1-97) was necessary for interaction with NtDXS. Using in vitro enzyme activity assays, PVY HC-Pro was found to promote the synthase activity of NtDXS. We observed increases in photosynthetic pigment contents and ABA levels in transgenic plants with HC-Pro accumulating in the chloroplasts. During virus infection, the enhancement of plastidic isoprenoid biosynthesis was attributed to the enhancement of DXS activity by HC-Pro. Our study reveals a new role of HC-Pro in the host plant metabolic system and will contribute to the study of host-virus relationships.
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Affiliation(s)
- Heng Li
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Dongyuan Ma
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yongsheng Jin
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Yayi Tu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Liping Liu
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chunxu Leng
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jiangli Dong
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Tao Wang
- State Key Laboratory of Agro-Biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
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35
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Bartee D, Morris F, Al-Khouja A, Freel Meyers CL. Hydroxybenzaldoximes Are D-GAP-Competitive Inhibitors of E. coli 1-Deoxy-D-Xylulose-5-Phosphate Synthase. Chembiochem 2015; 16:1771-81. [PMID: 26174207 PMCID: PMC4609000 DOI: 10.1002/cbic.201500119] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Indexed: 11/05/2022]
Abstract
1-Deoxy-D-xylulose 5-phosphate (DXP) synthase is the first enzyme in the methylerythritol phosphate pathway to essential isoprenoids in pathogenic bacteria and apicomplexan parasites. In bacterial pathogens, DXP lies at a metabolic branch point, serving also as a precursor in the biosynthesis of vitamins B1 and B6, which are critical for central metabolism. In an effort to identify new bisubstrate analogue inhibitors that exploit the large active site and distinct mechanism of DXP synthase, a library of aryl mixed oximes was prepared and evaluated. Trihydroxybenzaldoximes emerged as reversible, low-micromolar inhibitors, competitive against D-glyceraldehyde 3-phosphate (D-GAP) and either uncompetitive or noncompetitive against pyruvate. Hydroxybenzaldoximes are the first class of D-GAP-competitive DXP synthase inhibitors, offering new tools for mechanistic studies of DXP synthase and a new direction for the development of antimicrobial agents targeting isoprenoid biosynthesis.
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Affiliation(s)
- David Bartee
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205 (USA)
| | - Francine Morris
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205 (USA)
- Present address: Albert Einstein College of Medicine, Department of Biochemistry, 1301 Morris Park Avenue, Bronx, NY 10461 (USA)
| | - Amer Al-Khouja
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205 (USA)
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe Street, Baltimore, MD 21205 (USA).
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36
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Masini T, Lacy B, Monjas L, Hawksley D, de Voogd AR, Illarionov B, Iqbal A, Leeper FJ, Fischer M, Kontoyianni M, Hirsch AKH. Validation of a homology model of Mycobacterium tuberculosis DXS: rationalization of observed activities of thiamine derivatives as potent inhibitors of two orthologues of DXS. Org Biomol Chem 2015; 13:11263-77. [DOI: 10.1039/c5ob01666e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We present the a homology model ofM. tuberculosisDXS that we validated by identifying thiamine and thiamine diphosphate analogues as potent inhibitors of DXS.
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Jordan F, Nemeria NS. Progress in the experimental observation of thiamin diphosphate-bound intermediates on enzymes and mechanistic information derived from these observations. Bioorg Chem 2014; 57:251-262. [PMID: 25228115 DOI: 10.1016/j.bioorg.2014.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 08/11/2014] [Indexed: 11/26/2022]
Abstract
Thiamin diphosphate (ThDP), the vitamin B1 coenzyme is an excellent representative of coenzymes, which carry out electrophilic catalysis by forming a covalent complex with their substrates. The function of ThDP is to greatly increase the acidity of two carbon acids by stabilizing their conjugate bases, the ylide/carbene/C2-carbanion of the thiazolium ring and the C2α-carbanion/enamine, once the substrate binds to ThDP. In recent years, several ThDP-bound intermediates on such pathways have been characterized by both solution and solid-state methods. Prominent among these advances are X-ray crystallographic results identifying both oxidative and non-oxidative intermediates, rapid chemical quench followed by NMR detection of several intermediates which are stable under acidic conditions, solid-state NMR and circular dichroism detection of the states of ionization and tautomerization of the 4'-aminopyrimidine moiety of ThDP in some of the intermediates. These methods also enabled in some cases determination of the rate-limiting step in the complex series of steps. This review is an update of a review with the same title published by the authors in 2005 in this Journal. Much progress has been made in the intervening decade in the identification of the intermediates and their application to gain additional mechanistic insight.
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Affiliation(s)
- Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ 07102, USA.
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38
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Basta LAB, Patel H, Kakalis L, Jordan F, Meyers CLF. Defining critical residues for substrate binding to 1-deoxy-D-xylulose 5-phosphate synthase--active site substitutions stabilize the predecarboxylation intermediate C2α-lactylthiamin diphosphate. FEBS J 2014; 281:2820-2837. [PMID: 24767541 PMCID: PMC4065394 DOI: 10.1111/febs.12823] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2013] [Revised: 04/06/2014] [Accepted: 04/18/2014] [Indexed: 10/25/2022]
Abstract
1-Deoxy-D-xylulose 5-phosphate (DXP) synthase catalyzes the formation of DXP from pyruvate and D-glyceraldehyde 3-phosphate (GraP) in a thiamin diphosphate-dependent manner, and is the first step in the essential pathway to isoprenoids in human pathogens. Understanding the mechanism of this unique enzyme is critical for developing new anti-infective agents that selectively target isoprenoid biosynthesis. The present study used mutagenesis and a combination of protein fluorescence, CD and kinetics experiments to investigate the roles of Arg420, Arg478 and Tyr392 in substrate binding and catalysis. The results support a random sequential, preferred order mechanism, and predict that Arg420 and Arg478 are involved in binding of the acceptor substrate, GraP. D-Glyceraldehyde, an alternative acceptor substrate lacking the phosphoryl group predicted to interact with Arg420 and Arg478, also accelerates decarboxylation of the predecarboxylation intermediate C2α-lactylthiamin diphosphate (LThDP) on DXP synthase, indicating that this binding interaction is not absolutely required, and that the hydroxyaldehyde sufficiently triggers decarboxylation. Unexpectedly, Tyr392 contributes to GraP affinity, and is not required for LThDP formation or its GraP-promoted decarboxylation. Time-resolved CD spectroscopy and NMR experiments indicate that LThDP is significantly stabilized on R420A and Y392F variants as compared with wild-type DXP synthase in the absence of acceptor substrate, but these substitutions do not appear to affect the rate of GraP-promoted LThDP decarboxylation in the presence of high levels of GraP, and LThDP formation remains the rate-limiting step. These results suggest a role of these residues in promoting GraP binding, which in turn facilitates decarboxylation, and also highlight interesting differences between DXP synthase and other thiamin diphosphate-dependent enzymes.
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Affiliation(s)
- Leighanne A. Brammer Basta
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Hetalben Patel
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Lazaros Kakalis
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Frank Jordan
- Department of Chemistry, Rutgers University, Newark, New Jersey 07102
| | - Caren L. Freel Meyers
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
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39
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Patel H, Nemeria NS, Andrews FH, McLeish MJ, Jordan F. Identification of charge transfer transitions related to thiamin-bound intermediates on enzymes provides a plethora of signatures useful in mechanistic studies. Biochemistry 2014; 53:2145-52. [PMID: 24628377 PMCID: PMC3985856 DOI: 10.1021/bi4015743] [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: 11/28/2022]
Abstract
![]()
Identification
of enzyme-bound intermediates via their spectroscopic
signatures, which then allows direct monitoring of the kinetic fate
of these intermediates, poses a continuing challenge. As an electrophilic
covalent catalyst, the thiamin diphosphate (ThDP) coenzyme forms a
number of noncovalent and covalent intermediates along its reaction
pathways, and multiple UV–vis and circular dichroism (CD) bands
have been identified at Rutgers pertinent to several among them. These
electronic transitions fall into two classes: those for which the
conjugated system provides a reasonable guide to the observed λmax and others in which there is no corresponding conjugated
system and the observed CD bands are best ascribed to charge transfer
(CT) transitions. Herein is reported the reaction of four ThDP enzymes
with alternate substrates: (a) acetyl pyruvate, its methyl ester,
and fluoropyruvate, these providing the shortest side chains attached
at the thiazolium C2 atom and leading to CT bands with λmax values of >390 nm, not pertinent to any on-pathway conjugated
systems (estimated λmax values of <330 nm), and
(b) (E)-4-(4-chlorophenyl)-2-oxo-3-butenoic acid
displaying both a conjugated enamine (430 nm) and a CT transition
(480 nm). We suggest that the CT transitions result from an interaction
of the π bond on the ThDP C2 side chain as a donor, and the
positively charged thiazolium ring as an acceptor, and correspond
to covalent ThDP-bound intermediates. Time resolution of these bands
allows the rate constants for individual steps to be determined. These
CD methods can be applied to the entire ThDP superfamily of enzymes
and should find applications with other enzymes.
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Affiliation(s)
- Hetalben Patel
- Department of Chemistry, Rutgers, the State University of New Jersey , Newark, New Jersey 07102, United States
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40
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Smith JM, Warrington NV, Vierling RJ, Kuhn ML, Anderson WF, Koppisch AT, Freel Meyers CL. Targeting DXP synthase in human pathogens: enzyme inhibition and antimicrobial activity of butylacetylphosphonate. J Antibiot (Tokyo) 2014; 67:77-83. [PMID: 24169798 PMCID: PMC3946878 DOI: 10.1038/ja.2013.105] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 09/20/2013] [Accepted: 09/30/2013] [Indexed: 11/24/2022]
Abstract
The unique methylerythritol phosphate pathway for isoprenoid biosynthesis is essential in most bacterial pathogens. The first enzyme in this pathway, 1-deoxy-D-xylulose 5-phosphate (DXP) synthase, catalyzes a distinct thiamin diphosphate (ThDP)-dependent reaction to form DXP from D-glyceraldehyde 3-phosphate (D-GAP) and pyruvate and represents a potential anti-infective drug target. We have previously demonstrated that the unnatural bisubstrate analog, butylacetylphosphonate (BAP), exhibits selective inhibition of Escherichia coli DXP synthase over mammalian ThDP-dependent enzymes. Here, we report the selective inhibition by BAP against recombinant DXP synthase homologs from Mycobacterium tuberculosis, Yersinia pestis and Salmonella enterica. We also demonstrate antimicrobial activity of BAP against both Gram-negative and Gram-positive strains (including E. coli, S. enterica and Bacillus anthracis), and several clinically isolated pathogens. Our results suggest a mechanism of action involving inhibition of DXP synthase and show that BAP acts synergistically with established antimicrobial agents, highlighting a potential strategy to combat emerging resistance in bacterial pathogens.
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Affiliation(s)
- Jessica M Smith
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Nicole V Warrington
- Deptartment of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, AZ, USA
| | - Ryan J Vierling
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Misty L Kuhn
- Center for Structural Genomics of Infectious Diseases, Northwestern Feinberg School of Medicine, Department of Molecular Pharmacology and Biological Chemistry, Chicago, IL, USA
| | - Wayne F Anderson
- Center for Structural Genomics of Infectious Diseases, Northwestern Feinberg School of Medicine, Department of Molecular Pharmacology and Biological Chemistry, Chicago, IL, USA
| | - Andrew T Koppisch
- Deptartment of Chemistry and Biochemistry, Northern Arizona University, Flagstaff, AZ, USA
| | - Caren L Freel Meyers
- Department of Pharmacology and Molecular Sciences, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
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41
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Banerjee A, Sharkey TD. Methylerythritol 4-phosphate (MEP) pathway metabolic regulation. Nat Prod Rep 2014; 31:1043-55. [DOI: 10.1039/c3np70124g] [Citation(s) in RCA: 156] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The methylerythritol 4-phosphate pathway provides precursors for isoprenoids in bacteria, some eukaryotic parasites, and chloroplasts of plants. Metabolic regulatory mechanisms control flux through the pathway and the concentration of a central intermediate, methylerythritol cyclodiphosphate.
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Affiliation(s)
- A. Banerjee
- Department of Biochemistry and Molecular Biology
- Michigan State University
- East Lansing, 48824 USA
| | - T. D. Sharkey
- Department of Biochemistry and Molecular Biology
- Michigan State University
- East Lansing, 48824 USA
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42
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Masini T, Pilger J, Kroezen BS, Illarionov B, Lottmann P, Fischer M, Griesinger C, Hirsch AKH. De novo fragment-based design of inhibitors of DXS guided by spin-diffusion-based NMR spectroscopy. Chem Sci 2014. [DOI: 10.1039/c4sc00588k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
A ligand-based NMR methodology (STI) enabled de novo fragment-based design of inhibitors of the enzyme DXS present in the non-mevalonate pathway in the absence of X-ray co-crystal structures.
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Affiliation(s)
- T. Masini
- Stratingh Institute for Chemistry
- University of Groningen
- NL-9747 AG Groningen, The Netherlands
| | - J. Pilger
- Max-Planck-Institute for Biophysical Chemisty
- 37077 Göttingen, Germany
| | - B. S. Kroezen
- Stratingh Institute for Chemistry
- University of Groningen
- NL-9747 AG Groningen, The Netherlands
| | - B. Illarionov
- Hamburg School of Food Science
- Institute of Food Chemistry
- Hamburg, Germany
| | - P. Lottmann
- Max-Planck-Institute for Biophysical Chemisty
- 37077 Göttingen, Germany
| | - M. Fischer
- Hamburg School of Food Science
- Institute of Food Chemistry
- Hamburg, Germany
| | - C. Griesinger
- Max-Planck-Institute for Biophysical Chemisty
- 37077 Göttingen, Germany
| | - A. K. H. Hirsch
- Stratingh Institute for Chemistry
- University of Groningen
- NL-9747 AG Groningen, The Netherlands
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43
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Patel H, Shim DJ, Farinas ET, Jordan F. Investigation of the donor and acceptor range for chiral carboligation catalyzed by the E1 component of the 2-oxoglutarate dehydrogenase complex. ACTA ACUST UNITED AC 2013; 98. [PMID: 24277992 DOI: 10.1016/j.molcatb.2013.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The potential of thiamin diphosphate (ThDP)-dependent enzymes to catalyze C-C bond forming (carboligase) reactions with high enantiomeric excess has been recognized for many years. Here we report the application of the E1 component of the Escherichia coli 2-oxoglutarate dehydrogenase multienzyme complex in the synthesis of chiral compounds with multiple functional groups in good yield and high enantiomeric excess, by varying both the donor substrate (different 2-oxo acids) and the acceptor substrate (glyoxylate, ethyl glyoxylate and methyl glyoxal). Major findings include the demonstration that the enzyme can accept 2-oxovalerate and 2-oxoisovalerate in addition to its natural substrate 2-oxoglutarate, and that the tested acceptors are also acceptable in the carboligation reaction, thereby very much expanding the repertory of the enzyme in chiral synthesis.
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Affiliation(s)
- Hetalben Patel
- Department of Chemistry, Rutgers University, Newark, NJ 07102
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44
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Jordan F, Patel H. Catalysis in Enzymatic Decarboxylations: Comparison of Selected Cofactor-dependent and Cofactor-independent Examples. ACS Catal 2013; 3:1601-1617. [PMID: 23914308 DOI: 10.1021/cs400272x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
This review is focused on three types of enzymes decarboxylating very different substrates: (1) Thiamin diphosphate (ThDP)-dependent enzymes reacting with 2-oxo acids; (2) Pyridoxal phosphate (PLP)-dependent enzymes reacting with α-amino acids; and (3) An enzyme with no known co-factors, orotidine 5'-monophosphate decarboxylase (OMPDC). While the first two classes have been much studied for many years, during the past decade studies of both classes have revealed novel mechanistic insight challenging accepted understanding. The enzyme OMPDC has posed a challenge to the enzymologist attempting to explain a 1017-fold rate acceleration in the absence of cofactors or even metal ions. A comparison of the available evidence on the three types of decarboxylases underlines some common features and more differences. The field of decarboxylases remains an interesting and challenging one for the mechanistic enzymologist notwithstanding the large amount of information already available.
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Affiliation(s)
- Frank Jordan
- Department of Chemistry, Rutgers, The State University of New Jersey, 73 Warren Street, Newark,
New Jersey 07102, United States
| | - Hetalben Patel
- Department of Chemistry, Rutgers, The State University of New Jersey, 73 Warren Street, Newark,
New Jersey 07102, United States
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45
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Morris F, Vierling R, Boucher L, Bosch J, Freel Meyers CL. DXP synthase-catalyzed C-N bond formation: nitroso substrate specificity studies guide selective inhibitor design. Chembiochem 2013; 14:1309-15. [PMID: 23824585 DOI: 10.1002/cbic.201300187] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Indexed: 11/12/2022]
Abstract
1-Deoxy-D-xylulose 5-phosphate (DXP) synthase catalyzes the first step in the nonmammalian isoprenoid biosynthetic pathway to form DXP from pyruvate and D-glyceraldehyde 3-phosphate (D-GAP) in a thiamin diphosphate-dependent manner. Its unique structure and mechanism distinguish DXP synthase from its homologues and suggest that it should be pursued as an anti-infective drug target. However, few reports describe any development of selective inhibitors of this enzyme. Here, we reveal that DXP synthase catalyzes C-N bond formation and exploit aromatic nitroso substrates as active site probes. Substrate specificity studies reveal a high affinity of DXP synthase for aromatic nitroso substrates compared to the related ThDP-dependent enzyme pyruvate dehydrogenase (PDH). Results from inhibition and mutagenesis studies indicate that nitroso substrates bind to E. coli DXP synthase in a manner distinct from that of D-GAP. Our results suggest that the incorporation of aryl acceptor substrate mimics into unnatural bisubstrate analogues will impart selectivity to DXP synthase inhibitors. As a proof of concept, we show selective inhibition of DXP synthase by benzylacetylphosphonate (BnAP).
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Affiliation(s)
- Francine Morris
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, 725 North Wolfe St, Baltimore, MD 21205, USA
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46
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Balakrishnan A, Jordan F, Nathan CF. Influence of allosteric regulators on individual steps in the reaction catalyzed by Mycobacterium tuberculosis 2-hydroxy-3-oxoadipate synthase. J Biol Chem 2013; 288:21688-702. [PMID: 23760263 DOI: 10.1074/jbc.m113.465419] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Allosteric regulation often controls key branch points in metabolic processes. Mycobacterium tuberculosis 2-hydroxy-3-oxoadipate synthase (HOAS), a thiamin diphosphate (ThDP)-dependent enzyme, produces 2-hydroxy-3-oxoadipate using 2-ketoglutarate and glyoxylate. The proposed chemical mechanism in analogy with other ThDP-dependent carboligases involves multiple ThDP-bound covalent intermediates. Acetyl coenzyme A is an activator, and GarA, a forkhead association domain-containing protein known to regulate glutamate metabolism, is an allosteric inhibitor of HOAS. Steady state kinetics using assays to study the first half and the full catalytic cycle suggested that the regulators act at different steps in the overall mechanism. To explore the modes of regulation and to test the effects on individual catalytic steps, we performed circular dichroism (CD) studies using a non-decarboxylatable 2-ketoglutarate analog and determined the distribution of ThDP-bound covalent intermediates during the steady state of the HOAS reaction using one-dimensional (1)H gradient carbon heteronuclear single quantum coherence NMR. The results suggest that acetyl coenzyme A acts as a mixed V and K type activator and predominantly affects the predecarboxylation steps. GarA does not inhibit the formation of the predecarboxylation analog and does not affect the accumulation of the postdecarboxylation covalent intermediate derived from 2-ketoglutarate; however, it decreases the abundance of the product ThDP adduct in the HOAS pathway. Thus, the two regulators act on different halves of the catalytic cycle in an unusual regulatory regime.
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Affiliation(s)
- Anand Balakrishnan
- Department of Microbiology and Immunology, Weill Cornell Medical College, New York, New York 10065, USA
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Banerjee A, Wu Y, Banerjee R, Li Y, Yan H, Sharkey TD. Feedback inhibition of deoxy-D-xylulose-5-phosphate synthase regulates the methylerythritol 4-phosphate pathway. J Biol Chem 2013; 288:16926-16936. [PMID: 23612965 DOI: 10.1074/jbc.m113.464636] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway leads to the biosynthesis of isopentenyl diphosphate (IDP) and dimethylallyl diphosphate (DMADP), the precursors for isoprene and higher isoprenoids. Isoprene has significant effects on atmospheric chemistry, whereas other isoprenoids have diverse roles ranging from various biological processes to applications in commercial uses. Understanding the metabolic regulation of the MEP pathway is important considering the numerous applications of this pathway. The 1-deoxy-D-xylulose-5-phosphate synthase (DXS) enzyme was cloned from Populus trichocarpa, and the recombinant protein (PtDXS) was purified from Escherichia coli. The steady-state kinetic parameters were measured by a coupled enzyme assay. An LC-MS/MS-based assay involving the direct quantification of the end product of the enzymatic reaction, 1-deoxy-D-xylulose 5-phosphate (DXP), was developed. The effect of different metabolites of the MEP pathway on PtDXS activity was tested. PtDXS was inhibited by IDP and DMADP. Both of these metabolites compete with thiamine pyrophosphate for binding with the enzyme. An atomic structural model of PtDXS in complex with thiamine pyrophosphate and Mg(2+) was built by homology modeling and refined by molecular dynamics simulations. The refined structure was used to model the binding of IDP and DMADP and indicated that IDP and DMADP might bind with the enzyme in a manner very similar to the binding of thiamine pyrophosphate. The feedback inhibition of PtDXS by IDP and DMADP constitutes an important mechanism of metabolic regulation of the MEP pathway and indicates that thiamine pyrophosphate-dependent enzymes may often be affected by IDP and DMADP.
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Affiliation(s)
- Aparajita Banerjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Yan Wu
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Rahul Banerjee
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Yue Li
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824
| | - Honggao Yan
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824.
| | - Thomas D Sharkey
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, Michigan 48824.
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Avoiding CO2 in Catalysis of Decarboxylation. ADVANCES IN PHYSICAL ORGANIC CHEMISTRY 2013. [DOI: 10.1016/b978-0-12-407754-6.00002-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register]
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Jordan F, Nemeria NS. Experimental observation of thiamin diphosphate-bound intermediates on enzymes and mechanistic information derived from these observations. Bioorg Chem 2005; 33:190-215. [PMID: 15888311 PMCID: PMC4189838 DOI: 10.1016/j.bioorg.2005.02.001] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2004] [Revised: 02/08/2005] [Accepted: 02/10/2005] [Indexed: 11/27/2022]
Abstract
Thiamin diphosphate (ThDP), the vitamin B1 coenzyme, is an excellent representative of coenzymes, which carry out electrophilic catalysis by forming a covalent complex with their substrates. The function of ThDP is to greatly increase the acidity of two carbon acids by stabilizing their conjugate bases, the ylide/C2-carbanion of the thiazolium ring and the C2alpha-carbanion (or enamine) once the substrate binds to ThDP. In recent years, several ThDP-bound intermediates on such pathways have been characterized by both solution and solid-state (X-ray) methods. Prominent among these advances are X-ray crystallographic results identifying both oxidative and non-oxidative intermediates, rapid chemical quench followed by NMR detection of a several intermediates which are stable under acidic conditions, and circular dichroism detection of the 1',4'-imino tautomer of ThDP in some of the intermediates. Some of these methods also enable the investigator to determine the rate-limiting step in the complex series of steps.
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Affiliation(s)
- Frank Jordan
- Department of Chemistry, Rutgers University, Newark, NJ 07102, USA
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