1
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Jaroensuk J, Chuaboon L, Kesornpun C, Chaiyen P. Enzymes in riboflavin biosynthesis: Potential antibiotic drug targets. Arch Biochem Biophys 2023; 748:109762. [PMID: 37739114 DOI: 10.1016/j.abb.2023.109762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 09/13/2023] [Accepted: 09/19/2023] [Indexed: 09/24/2023]
Abstract
The rapid resistance of pathogens to antibiotics has emerged as a major threat to global health. Identification of new antibiotic targets is thus needed for developing alternative drugs. Genes encoding enzymes involved in the biosynthesis of riboflavin and flavin cofactors (FMN/FAD) are attractive targets because these enzymatic reactions are necessary for most bacteria to synthesize flavin cofactors for use in their central metabolic reactions. Moreover, humans lack most of these enzymes because we uptake riboflavin from our diet. This review discusses the current knowledge of enzymes involved in bacterial biosynthesis of riboflavin and other flavin cofactors, as well as the functions of the FMN riboswitch. Here, we highlight recent progress in the structural and mechanistic characterization, and inhibition of GTP cyclohydrolase II (GCH II), lumazine synthase (LS), riboflavin synthase (RFS), FAD synthetase (FADS), and FMN riboswitch, which have been identified as plausible antibiotic targets. As the structures and functions of these enzymes and regulatory systems are not completely understood, they are attractive as subjects for future in-depth biochemical and biophysical analysis.
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Affiliation(s)
- Juthamas Jaroensuk
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand
| | - Litavadee Chuaboon
- School of Pharmacy and Biomass and Oil Palm Center of Excellence, Walailak University, Nakhon Si Thammarat, 80160, Thailand
| | - Chatchai Kesornpun
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand
| | - Pimchai Chaiyen
- School of Biomolecular Science and Engineering, Vidyasirimedhi Institute of Science and Technology (VISTEC), Wangchan Valley, Wangchan, Rayong, 21210, Thailand.
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2
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Islam Z, Kumar P. Inhibitors of riboflavin biosynthetic pathway enzymes as potential antibacterial drugs. Front Mol Biosci 2023; 10:1228763. [PMID: 37496776 PMCID: PMC10366380 DOI: 10.3389/fmolb.2023.1228763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Accepted: 07/03/2023] [Indexed: 07/28/2023] Open
Abstract
Multiple drug resistance is the main obstacle in the treatment of bacterial diseases. Resistance against antibiotics demands the exploration of new antimicrobial drug targets. A variety of in silico and genetic approaches show that the enzymes of the riboflavin biosynthetic pathway are crucial for the survival of bacteria. This pathway is absent in humans thus enzymes of the riboflavin biosynthetic pathway are emerging drug targets for resistant pathogenic bacterial strains. Exploring the structural details, their mechanism of action, intermediate elucidation, and interaction analysis would help in designing suitable inhibitors of these enzymes. The riboflavin biosynthetic pathway consists of seven distinct enzymes, namely, 3,4-dihydroxy-2-butanone 4-phosphate synthase, GTP cyclohydrolase II, pyrimidine deaminase/reductase, phosphatase, lumazine synthase, and riboflavin synthase. The present review summarizes the research work that has been carried out on these enzymes in terms of their structures, active site architectures, and molecular mechanism of catalysis. This review also walks through small molecule inhibitors that have been developed against several of these enzymes.
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Affiliation(s)
- Zeyaul Islam
- Qatar Biomedical Research Institute (QBRI), Qatar Foundation, Hamad Bin Khalifa University, Doha, Qatar
| | - Pankaj Kumar
- Department of Biochemistry, Jamia Hamdard, New Delhi, India
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3
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Shingare RD, MacMillan JB, Reddy DS. Antibiotic natural product hunanamycin A: Lead identification towards anti-Salmonella agents. Eur J Med Chem 2022; 236:114245. [DOI: 10.1016/j.ejmech.2022.114245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/10/2022] [Accepted: 02/26/2022] [Indexed: 11/30/2022]
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4
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Daniels BJ, Li FF, Furkert DP, Brimble MA. Naturally Occurring Lumazines. JOURNAL OF NATURAL PRODUCTS 2019; 82:2054-2065. [PMID: 31317731 DOI: 10.1021/acs.jnatprod.9b00351] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Natural products containing a lumazine motif were first isolated from natural sources in 1940. These natural products are relatively rare, with fewer than 100 lumazines known to occur in Nature. This review discusses the isolation of lumazines, their biological activity, and their biosynthesis, where known.
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Affiliation(s)
- Benjamin J Daniels
- School of Chemical Sciences , The University of Auckland , 23 Symonds Street , Auckland 1010 , New Zealand
| | - Freda F Li
- School of Chemical Sciences , The University of Auckland , 23 Symonds Street , Auckland 1010 , New Zealand
| | - Daniel P Furkert
- School of Chemical Sciences , The University of Auckland , 23 Symonds Street , Auckland 1010 , New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , 3 Symonds Street , Auckland 1010 , New Zealand
| | - Margaret A Brimble
- School of Chemical Sciences , The University of Auckland , 23 Symonds Street , Auckland 1010 , New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery , The University of Auckland , 3 Symonds Street , Auckland 1010 , New Zealand
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5
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Marín-Valls R, Hernández K, Bolte M, Joglar J, Bujons J, Clapés P. Chemoenzymatic Hydroxymethylation of Carboxylic Acids by Tandem Stereodivergent Biocatalytic Aldol Reaction and Chemical Decarboxylation. ACS Catal 2019. [DOI: 10.1021/acscatal.9b01646] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Roser Marín-Valls
- Instituto de Química Avanzada de Cataluña IQAC−CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Karel Hernández
- Instituto de Química Avanzada de Cataluña IQAC−CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Michael Bolte
- Institut für Anorganische Chemie, J.-W.-Goethe-Universität, D-60438 Frankfurt/Main, Germany
| | - Jesús Joglar
- Instituto de Química Avanzada de Cataluña IQAC−CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Jordi Bujons
- Instituto de Química Avanzada de Cataluña IQAC−CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
| | - Pere Clapés
- Instituto de Química Avanzada de Cataluña IQAC−CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain
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6
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Serer MI, Carrica MDC, Trappe J, López Romero S, Bonomi HR, Klinke S, Cerutti ML, Goldbaum FA. A high-throughput screening for inhibitors of riboflavin synthase identifies novel antimicrobial compounds to treat brucellosis. FEBS J 2019; 286:2522-2535. [PMID: 30927485 DOI: 10.1111/febs.14829] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/26/2019] [Accepted: 03/29/2019] [Indexed: 10/27/2022]
Abstract
Brucella spp. are pathogenic intracellular Gram-negative bacteria adapted to life within cells of several mammals, including humans. These bacteria are the causative agent of brucellosis, one of the zoonotic infections with the highest incidence in the world and for which a human vaccine is still unavailable. Current therapeutic treatments against brucellosis are based on the combination of two or more antibiotics for prolonged periods, which may lead to antibiotic resistance in the population. Riboflavin (vitamin B2) is biosynthesized by microorganisms and plants but mammals, including humans, must obtain it from dietary sources. Owing to the absence of the riboflavin biosynthetic enzymes in animals, this pathway is nowadays regarded as a rich resource of targets for the development of new antimicrobial agents. In this work, we describe a high-throughput screening approach to identify inhibitors of the enzymatic activity of riboflavin synthase, the last enzyme in this pathway. We also provide evidence for their subsequent validation as potential drug candidates in an in vitro brucellosis infection model. From an initial set of 44 000 highly diverse low molecular weight compounds with drug-like properties, we were able to identify ten molecules with 50% inhibitory concentrations in the low micromolar range. Further Brucella culture and intramacrophagic replication experiments showed that the most effective bactericidal compounds share a 2-Phenylamidazo[2,1-b][1,3]benzothiazole chemical scaffold. Altogether, these findings set up the basis for the subsequent lead optimization process and represent a promising advancement in the pursuit of novel and effective antimicrobial compounds against brucellosis.
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Affiliation(s)
- María Inés Serer
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | | | - Jörg Trappe
- Novartis Institutes for BioMedical Research, Basel, Switzerland
| | | | | | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
| | - María Laura Cerutti
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
| | - Fernando Alberto Goldbaum
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina.,Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires, Argentina
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7
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Kundu B, Sarkar D, Ray N, Talukdar A. Understanding the riboflavin biosynthesis pathway for the development of antimicrobial agents. Med Res Rev 2019; 39:1338-1371. [PMID: 30927319 DOI: 10.1002/med.21576] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2018] [Revised: 02/14/2019] [Accepted: 03/08/2019] [Indexed: 12/13/2022]
Abstract
Life on earth depends on the biosynthesis of riboflavin, which plays a vital role in biological electron transport processes. Higher mammals obtain riboflavin from dietary sources; however, various microorganisms, including Gram-negative pathogenic bacteria and yeast, lack an efficient riboflavin-uptake system and are dependent on endogenous riboflavin biosynthesis. Consequently, the inhibition of enzymes in the riboflavin biosynthesis pathway would allow selective toxicity to a pathogen and not the host. Thus, the riboflavin biosynthesis pathway is an attractive target for designing novel antimicrobial drugs, which are urgently needed to address the issue of multidrug resistance seen in various pathogens. The enzymes involved in riboflavin biosynthesis are lumazine synthase (LS) and riboflavin synthase (RS). Understanding the details of the mechanisms of the enzyme-catalyzed reactions and the structural changes that occur in the enzyme active sites during catalysis can facilitate the design and synthesis of suitable analogs that can specifically inhibit the relevant enzymes and stop the generation of riboflavin in pathogenic bacteria. The present review is the first compilation of the work that has been carried out over the last 25 years focusing on the design of inhibitors of the biosynthesis of riboflavin based on an understanding of the mechanisms of LS and RS. This review aimed to address the fundamental advances in our understanding of riboflavin biosynthesis as applied to the rational design of a novel class of inhibitors. These advances have been aided by X-ray structures of ligand-enzyme complexes, rotational-echo, double-resonance nuclear magnetic resonance spectroscopy, high-throughput screening, virtual screenings, and various mechanistic probes.
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Affiliation(s)
- Biswajit Kundu
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, Kolkata, India
| | - Dipayan Sarkar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, Kolkata, India.,Academy of Scientific and Innovative Research, Kolkata, India
| | - Namrata Ray
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, Kolkata, India.,Department of Chemistry, Adamas University, Kolkata, India
| | - Arindam Talukdar
- Department of Organic and Medicinal Chemistry, CSIR-Indian Institute of Chemical Biology, Kolkata, India.,Academy of Scientific and Innovative Research, Kolkata, India
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8
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Harriff MJ, McMurtrey C, Froyd CA, Jin H, Cansler M, Null M, Worley A, Meermeier EW, Swarbrick G, Nilsen A, Lewinsohn DA, Hildebrand W, Adams EJ, Lewinsohn DM. MR1 displays the microbial metabolome driving selective MR1-restricted T cell receptor usage. Sci Immunol 2019; 3:3/25/eaao2556. [PMID: 30006464 PMCID: PMC7085347 DOI: 10.1126/sciimmunol.aao2556] [Citation(s) in RCA: 94] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2017] [Revised: 02/05/2018] [Accepted: 06/04/2018] [Indexed: 12/11/2022]
Abstract
MR1-restricted T cells (MR1Ts) are a T cell subset that recognize and mediate host defense to a broad array of microbial pathogens, including respiratory pathogens (e.g., Mycobacterium tuberculosis, Streptococcus pyogenes, and Francisella tularensis) and enteric pathogens (e.g., Escherichia coli and Salmonella species). Mucosal-associated invariant T (MAIT) cells, a subset of MR1Ts, were historically defined by the use of a semi-invariant T cell receptor (TCR) and recognition of small molecules derived from the riboflavin biosynthesis pathway presented on MR1. We used mass spectrometry to identify the repertoire of ligands presented by MR1 from the microbes E. coli and Mycobacterium smegmatis. We found that the MR1 ligandome is unexpectedly broad, revealing functionally distinct ligands derived from E. coli and M. smegmatis. The identification, synthesis, and functional analysis of mycobacterial ligands reveal that MR1T ligands can be distinguished by MR1Ts with diverse TCR usage. These data demonstrate that MR1 can serve as an immune sensor of the microbial ligandome.
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Affiliation(s)
- Melanie J Harriff
- VA Portland Health Care System, Research and Development, 3710 Southwest U.S. Veterans Hospital Road, Portland, OR 97239, USA.,Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239, USA
| | - Curtis McMurtrey
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Cara A Froyd
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Haihong Jin
- Oregon Health & Science University Medicinal Chemistry Core, Portland, OR 97239, USA
| | - Meghan Cansler
- Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Megan Null
- Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Aneta Worley
- VA Portland Health Care System, Research and Development, 3710 Southwest U.S. Veterans Hospital Road, Portland, OR 97239, USA
| | - Erin W Meermeier
- Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239, USA
| | - Gwendolyn Swarbrick
- Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - Aaron Nilsen
- VA Portland Health Care System, Research and Development, 3710 Southwest U.S. Veterans Hospital Road, Portland, OR 97239, USA.,Oregon Health & Science University Medicinal Chemistry Core, Portland, OR 97239, USA.,Department of Molecular Microbiology and Immunology, Oregon Health & Science University, Portland, OR 97239, USA
| | - Deborah A Lewinsohn
- Department of Pediatrics, Oregon Health & Science University, Portland, OR 97239, USA
| | - William Hildebrand
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Erin J Adams
- Department of Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA.
| | - David M Lewinsohn
- VA Portland Health Care System, Research and Development, 3710 Southwest U.S. Veterans Hospital Road, Portland, OR 97239, USA. .,Department of Pulmonary and Critical Care Medicine, Oregon Health & Science University, 3181 Southwest Sam Jackson Park Road, Portland, OR 97239, USA
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9
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Discovery of potential lumazine synthase antagonists for pathogens involved in bacterial meningitis: In silico study. INFORMATICS IN MEDICINE UNLOCKED 2019. [DOI: 10.1016/j.imu.2019.100187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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10
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Wei Y, Kumar P, Wahome N, Mantis NJ, Middaugh CR. Biomedical Applications of Lumazine Synthase. J Pharm Sci 2018; 107:2283-2296. [DOI: 10.1016/j.xphs.2018.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Revised: 05/02/2018] [Accepted: 05/02/2018] [Indexed: 10/16/2022]
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11
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Kjer-Nielsen L, Corbett AJ, Chen Z, Liu L, Mak JY, Godfrey DI, Rossjohn J, Fairlie DP, McCluskey J, Eckle SB. An overview on the identification of MAIT cell antigens. Immunol Cell Biol 2018; 96:573-587. [PMID: 29656544 DOI: 10.1111/imcb.12057] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Revised: 04/05/2018] [Accepted: 04/05/2018] [Indexed: 12/11/2022]
Abstract
Mucosal associated invariant T (MAIT) cells are restricted by the monomorphic MHC class I-like molecule, MHC-related protein-1 (MR1). Until 2012, the origin of the MAIT cell antigens (Ags) was unknown, although it was established that MAIT cells could be activated by a broad range of bacteria and yeasts, possibly suggesting a conserved Ag. Using a combination of protein chemistry, mass spectrometry, cellular biology, structural biology and small molecule chemistry, we discovered MR1 ligands derived from folic acid (vitamin B9) and from an intermediate in the microbial biosynthesis of riboflavin (vitamin B2). While the folate derivative 6-formylpterin generally inhibited MAIT cell activation, two riboflavin pathway derivatives, 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil and 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil, were potent MAIT cell agonists. Other intermediates and derivatives of riboflavin synthesis displayed weak or no MAIT cell activation. Collectively, these studies revealed that in addition to peptide and lipid-based Ags, small molecule natural product metabolites are also ligands that can activate T cells expressing αβ T-cell receptors, and here we recount this discovery.
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Affiliation(s)
- Lars Kjer-Nielsen
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Alexandra J Corbett
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Zhenjun Chen
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Ligong Liu
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Jeffrey Yw Mak
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Dale I Godfrey
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Melbourne, Melbourne, VIC, 3000, Australia
| | - Jamie Rossjohn
- Infection and Immunity Program, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.,Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, VIC, 3800, Australia.,Institute of Infection and Immunity, Cardiff University School of Medicine, Cardiff, CF14 4XN, UK
| | - David P Fairlie
- Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, 4072, Australia.,Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - James McCluskey
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
| | - Sidonia Bg Eckle
- Department of Microbiology and Immunology, The University of Melbourne at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, 3000, Australia
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12
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Eckle SBG, Corbett AJ, Keller AN, Chen Z, Godfrey DI, Liu L, Mak JYW, Fairlie DP, Rossjohn J, McCluskey J. Recognition of Vitamin B Precursors and Byproducts by Mucosal Associated Invariant T Cells. J Biol Chem 2015; 290:30204-11. [PMID: 26468291 DOI: 10.1074/jbc.r115.685990] [Citation(s) in RCA: 85] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Vitamin B2 (riboflavin) is essential for metabolic functions and is synthesized by many bacteria, yeast, and plants, but not by mammals and other animals, which must acquire it from the diet. In mammals, modified pyrimidine intermediates from the microbial biosynthesis of riboflavin are recognized as signature biomarkers of microbial infection. This recognition occurs by specialized lymphocytes known as mucosal associated invariant T (MAIT) cells. The major histocompatibility class I-like antigen-presenting molecule, MR1, captures these pyrimidine intermediates, but only after their condensation with small molecules derived from glycolysis and other metabolic pathways to form short-lived antigens. The resulting MR1-Ag complexes are recognized by MAIT cell antigen receptors (αβ T cell receptors (TCRs)), and the subsequent MAIT cell immune responses are thought to protect the host from pathogens at mucosal surfaces. Here, we review our understanding of how these novel antigens are generated and discuss their interactions with MR1 and MAIT TCRs.
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Affiliation(s)
- Sidonia B G Eckle
- From the Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, and
| | - Alexandra J Corbett
- From the Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, and
| | - Andrew N Keller
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia
| | - Zhenjun Chen
- From the Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, and
| | - Dale I Godfrey
- From the Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ligong Liu
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia, and the Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, and
| | - Jeffrey Y W Mak
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia, and the Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, and
| | - David P Fairlie
- Australian Research Council Centre of Excellence in Advanced Molecular Imaging, The University of Queensland, Brisbane, Queensland 4072, Australia, and the Division of Chemistry and Structural Biology, Institute for Molecular Bioscience, and
| | - Jamie Rossjohn
- the Infection and Immunity Program and Department of Biochemistry and Molecular Biology, Biomedicine Discovery Institute, and Australian Research Council Centre of Excellence in Advanced Molecular Imaging, Monash University, Clayton, Victoria 3800, Australia, the Institute of Infection and Immunity, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, United Kingdom
| | - James McCluskey
- From the Department of Microbiology and Immunology, The Peter Doherty Institute for Infection and Immunity, and
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13
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Haase I, Gräwert T, Illarionov B, Bacher A, Fischer M. Recent advances in riboflavin biosynthesis. Methods Mol Biol 2014; 1146:15-40. [PMID: 24764086 DOI: 10.1007/978-1-4939-0452-5_2] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Riboflavin is biosynthesized from GTP and ribulose 5-phosphate. Whereas the early reactions conducing to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione 5'-phosphate show significant taxonomic variation, the subsequent reaction steps are universal in all taxonomic kingdoms. With the exception of a hitherto elusive phosphatase, all enzymes of the pathway have been characterized in some detail at the structural and mechanistic level. Some of the pathway enzymes (GTP cycloyhdrolase II, 3,4-dihydroxy-2-butanone 4-phosphate synthase, riboflavin synthase) have exceptionally complex reaction mechanisms. The commercial production of the vitamin is now entirely based on highly productive fermentation processes. Due to their absence in animals, the pathway enzymes are potential targets for the development of novel anti-infective drugs.
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Affiliation(s)
- Ilka Haase
- Hamburg School of Food Science, Institute of Food Chemistry, University of Hamburg, Grindelallee 117, 20146, Hamburg, Germany
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14
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T-cell activation by transitory neo-antigens derived from distinct microbial pathways. Nature 2014; 509:361-5. [PMID: 24695216 DOI: 10.1038/nature13160] [Citation(s) in RCA: 599] [Impact Index Per Article: 59.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Accepted: 02/14/2014] [Indexed: 02/07/2023]
Abstract
T cells discriminate between foreign and host molecules by recognizing distinct microbial molecules, predominantly peptides and lipids. Riboflavin precursors found in many bacteria and yeast also selectively activate mucosal-associated invariant T (MAIT) cells, an abundant population of innate-like T cells in humans. However, the genesis of these small organic molecules and their mode of presentation to MAIT cells by the major histocompatibility complex (MHC)-related protein MR1 (ref. 8) are not well understood. Here we show that MAIT-cell activation requires key genes encoding enzymes that form 5-amino-6-d-ribitylaminouracil (5-A-RU), an early intermediate in bacterial riboflavin synthesis. Although 5-A-RU does not bind MR1 or activate MAIT cells directly, it does form potent MAIT-activating antigens via non-enzymatic reactions with small molecules, such as glyoxal and methylglyoxal, which are derived from other metabolic pathways. The MAIT antigens formed by the reactions between 5-A-RU and glyoxal/methylglyoxal were simple adducts, 5-(2-oxoethylideneamino)-6-D-ribitylaminouracil (5-OE-RU) and 5-(2-oxopropylideneamino)-6-D-ribitylaminouracil (5-OP-RU), respectively, which bound to MR1 as shown by crystal structures of MAIT TCR ternary complexes. Although 5-OP-RU and 5-OE-RU are unstable intermediates, they became trapped by MR1 as reversible covalent Schiff base complexes. Mass spectra supported the capture by MR1 of 5-OP-RU and 5-OE-RU from bacterial cultures that activate MAIT cells, but not from non-activating bacteria, indicating that these MAIT antigens are present in a range of microbes. Thus, MR1 is able to capture, stabilize and present chemically unstable pyrimidine intermediates, which otherwise convert to lumazines, as potent antigens to MAIT cells. These pyrimidine adducts are microbial signatures for MAIT-cell immunosurveillance.
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15
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Jung JE, Lee SY, Park H, Cha H, Ko W, Sachin K, Kim DW, Chi DY, Lee HS. Genetic incorporation of unnatural amino acids biosynthesized from α-keto acids by an aminotransferase. Chem Sci 2014. [DOI: 10.1039/c3sc51617b] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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Ladenstein R, Fischer M, Bacher A. The lumazine synthase/riboflavin synthase complex: shapes and functions of a highly variable enzyme system. FEBS J 2013; 280:2537-63. [PMID: 23551830 DOI: 10.1111/febs.12255] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2012] [Revised: 03/01/2013] [Accepted: 03/04/2013] [Indexed: 11/30/2022]
Abstract
The xylene ring of riboflavin (vitamin B2 ) is assembled from two molecules of 3,4-dihydroxy-2-butanone 4-phosphate by a mechanistically complex process that is jointly catalyzed by lumazine synthase and riboflavin synthase. In Bacillaceae, these enzymes form a structurally unique complex comprising an icosahedral shell of 60 lumazine synthase subunits and a core of three riboflavin synthase subunits, whereas many other bacteria have empty lumazine synthase capsids, fungi, Archaea and some eubacteria have pentameric lumazine synthases, and the riboflavin synthases of Archaea are paralogs of lumazine synthase. The structures of the molecular ensembles have been studied in considerable detail by X-ray crystallography, X-ray small-angle scattering and electron microscopy. However, certain mechanistic aspects remain unknown. Surprisingly, the quaternary structure of the icosahedral β subunit capsids undergoes drastic changes, resulting in formation of large, quasi-spherical capsids; this process is modulated by sequence mutations. The occurrence of large shells consisting of 180 or more lumazine synthase subunits has recently generated interest for protein engineering topics, particularly the construction of encapsulation systems.
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Affiliation(s)
- Rudolf Ladenstein
- Department of Bioscience and Nutrition, Karolinska Institutet NOVUM, SE-14183 Huddinge, Sweden.
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Ding H, Roberts AG, Harran PG. Synthetic (±)-Axinellamines Deficient in Halogen. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201200205] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Ding H, Roberts AG, Harran PG. Synthetic (±)-axinellamines deficient in halogen. Angew Chem Int Ed Engl 2012; 51:4340-3. [PMID: 22431425 DOI: 10.1002/anie.201200205] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Indexed: 11/10/2022]
Affiliation(s)
- Hui Ding
- Department of Chemistry and Biochemistry, University of California Los Angeles, 5505A Molecular Sciences Building, 607 Charles E. Young Drive East, Los Angeles, CA 90095-1569, USA
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Abstract
The biosynthesis of riboflavin requires 1 equivalent of GTP and 2 equivalents of ribulose phosphate. The first committed reactions of the convergent pathway are catalyzed by GTP hydrolase II and 3,4-dihydroxy-2-butanone 4-phosphate synthase. The initial reaction steps afford 5-amino-6-ribitylaminopyrimidine 5'-phosphate, which needs to be dephosphorylated by a hitherto elusive hydrolase. The dephosphorylated pyrimidine is condensed with the carbohydrate precursor, 3,4-dihydroxy-2-butanone 4-phosphate. The resulting 6,7-dimethyl-8-ribityllumazine affords riboflavin by a mechanistically unique dismutation, i.e., by formation of a pentacyclic dimer that is subsequently fragmented.
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Morgunova E, Illarionov B, Saller S, Popov A, Sambaiah T, Bacher A, Cushman M, Fischer M, Ladenstein R. Structural study and thermodynamic characterization of inhibitor binding to lumazine synthase from Bacillus anthracis. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:1001-11. [PMID: 20823551 PMCID: PMC2935281 DOI: 10.1107/s0907444910029690] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Accepted: 07/26/2010] [Indexed: 11/10/2022]
Abstract
The crystal structure of lumazine synthase from Bacillus anthracis was solved by molecular replacement and refined to R(cryst) = 23.7% (R(free) = 28.4%) at a resolution of 3.5 A. The structure reveals the icosahedral symmetry of the enzyme and specific features of the active site that are unique in comparison with previously determined orthologues. The application of isothermal titration calorimetry in combination with enzyme kinetics showed that three designed pyrimidine derivatives bind to lumazine synthase with micromolar dissociation constants and competitively inhibit the catalytic reaction. Structure-based modelling suggested the binding modes of the inhibitors in the active site and allowed an estimation of the possible contacts formed upon binding. The results provide a structural framework for the design of antibiotics active against B. anthracis.
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Affiliation(s)
- Ekaterina Morgunova
- Karolinska Institutet NOVUM, Center of Structural Biochemistry, Hälsovägen 7–9, 141 57 Huddinge, Sweden
| | - Boris Illarionov
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Sabine Saller
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Aleksander Popov
- European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble CEDEX 09, France
| | - Thota Sambaiah
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, USA
| | - Adelbert Bacher
- Chemistry Department, Technical University of Munich, 85747 Garching, Germany
| | - Mark Cushman
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, USA
| | - Markus Fischer
- Institut für Lebensmittelchemie, Universität Hamburg, Grindelallee 117, 20146 Hamburg, Germany
| | - Rudolf Ladenstein
- Karolinska Institutet NOVUM, Center of Structural Biochemistry, Hälsovägen 7–9, 141 57 Huddinge, Sweden
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Long Q, Ji L, Wang H, Xie J. Riboflavin Biosynthetic and Regulatory Factors as Potential Novel Anti-Infective Drug Targets. Chem Biol Drug Des 2010; 75:339-47. [DOI: 10.1111/j.1747-0285.2010.00946.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Discovery and development of the covalent hydrates of trifluoromethylated pyrazoles as riboflavin synthase inhibitors with antibiotic activity against Mycobacterium tuberculosis. J Org Chem 2009; 74:5297-303. [PMID: 19545132 DOI: 10.1021/jo900768c] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A high-throughput screening (HTS) hit compound displayed moderate inhibition of Mycobacterium tuberculosis and Escherichia coli riboflavin synthases. The structure of the hit compound provided by the commercial vendor was reassigned as [3-(4-chlorophenyl)-5-hydroxy-5-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-1-yl](o-tolyl)methanone (18). The hit compound had a k(is) of 8.7 microM vs. M. tuberculosis riboflavin synthase and moderate antibiotic activity against both M. tuberculosis replicating phenotype and nonreplicating persistent phenotype. Molecular modeling studies suggest that two inhibitor molecules bind in the active site of the enzyme, and that the binding is stabilized by stacking between the benzene rings of two adjacent ligands. The most potent antibiotic in the series proved to be [5-(4-chlorophenyl)-5-hydroxy-3-(trifluoromethyl)-4,5-dihydro-1H-pyrazol-1-yl](m-tolyl)methanone (16), which displayed a minimum inhibitory concentration (MIC) of 36.6 microM vs. M. tuberculosis replicating phenotype and 48.9 microM vs. M. tuberculosis nonreplicating phenotype. The HTS hit compound and its analogues provide the first examples of riboflavin synthase inhibitors with antibiotic activity.
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Koltun DO, Parkhill EQ, Vasilevich NI, Glushkov AI, Zilbershtein TM, Ivanov AV, Cole AG, Henderson I, Zautke NA, Brunn SA, Mollova N, Leung K, Chisholm JW, Zablocki J. Novel, potent, selective, and metabolically stable stearoyl-CoA desaturase (SCD) inhibitors. Bioorg Med Chem Lett 2009; 19:2048-52. [DOI: 10.1016/j.bmcl.2009.02.019] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2008] [Revised: 01/31/2009] [Accepted: 02/03/2009] [Indexed: 11/27/2022]
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Fischer M, Bacher A. Biosynthesis of vitamin B2: Structure and mechanism of riboflavin synthase. Arch Biochem Biophys 2008; 474:252-65. [PMID: 18298940 DOI: 10.1016/j.abb.2008.02.008] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2007] [Revised: 02/05/2008] [Accepted: 02/06/2008] [Indexed: 11/30/2022]
Abstract
The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate as substrates. GTP is hydrolytically opened, converted into 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction and dephosphorylation. Condensation with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate leads to 6,7-dimethyl-8-ribityllumazine. The final step in the biosynthesis of the vitamin involves the dismutation of 6,7-dimethyl-8-ribityllumazine catalyzed by riboflavin synthase. The mechanistically unusual reaction involves the transfer of a four-carbon fragment between two identical substrate molecules. The second product, 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, is recycled in the biosynthetic pathway by 6,7-dimethyl-8-ribityllumazine synthase. This article will review structures and reaction mechanisms of riboflavin synthases and related proteins up to 2007 and 122 references are cited.
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Affiliation(s)
- Markus Fischer
- Institute of Food Chemistry, University of Hamburg, Grindelallee 117, D-20146 Hamburg, Germany.
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Kaiser J, Illarionov B, Rohdich F, Eisenreich W, Saller S, den Brulle JV, Cushman M, Bacher A, Fischer M. A high-throughput screening platform for inhibitors of the riboflavin biosynthesis pathway. Anal Biochem 2007; 365:52-61. [PMID: 17400171 DOI: 10.1016/j.ab.2007.02.033] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2007] [Revised: 02/21/2007] [Accepted: 02/26/2007] [Indexed: 10/23/2022]
Abstract
3,4-Dihydroxy-2-butanone 4-phosphate synthase, 6,7-dimethyl-8-ribityllumazine synthase, and riboflavin synthase of the riboflavin biosynthetic pathway are potential targets for novel antiinfective drugs. This article describes a platform for high-throughput screening for inhibitors of these enzymes. The assays can be monitored photometrically and have been shown to be robust, as indicated by Z factors 0.87. A (13)C NMR assay for hit verification of 3,4-dihydroxy-2-butanone 4-phosphate synthase inhibitors is also reported.
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Affiliation(s)
- Johannes Kaiser
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, D-85748 München, Germany
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Zhang Y, Illarionov B, Bacher A, Fischer M, Georg GI, Ye QZ, Velde DV, Fanwick PE, Song Y, Cushman M. A novel lumazine synthase inhibitor derived from oxidation of 1,3,6,8-tetrahydroxy-2,7-naphthyridine to a tetraazaperylenehexaone derivative. J Org Chem 2007; 72:2769-76. [PMID: 17348709 PMCID: PMC2526313 DOI: 10.1021/jo062246d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Air oxidation of 1,3,6,8-tetrahydroxy-2,7-naphthyridine afforded 2,5,8,11-tetraaza-5,11-dihydro-4,10-dihydroxyperylene-1,3,6,7,9,12-hexaone. X-ray crystallography of the product revealed that it exists in the meso form in the solid state. The mechanism of product formation most likely involves oxidative phenolic coupling and oxidation. The product proved to be a competitive inhibitor of Schizosaccharomyces pombe lumazine synthase with a Ki of 66+/-13 microM in Tris buffer and 22+/-4 microM in phosphate buffer. This is significantly more potent than the reactant (Ki 350+/-76 microM, competitive inhibition), which had previously been identified as a lumazine synthase inhibitor by high-throughput screening. Ab initio calculations indicate that the meso form is slightly less stable than the enantiomeric form, and that the two forms interconvert rapidly at room temperature.
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Enders D, Bonten MH, Raabe G. Asymmetric Nucleophilic Glyoxylation through a Metalated α-Aminonitrile Derivative in Michael Additions to Nitroalkenes. Angew Chem Int Ed Engl 2007; 46:2314-6. [PMID: 17300124 DOI: 10.1002/anie.200604802] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
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Enders D, Bonten M, Raabe G. Asymmetrische nucleophile Glyoxylierung durch metallierte α-Aminonitril-Derivate in Michael-Additionen an Nitroalkene. Angew Chem Int Ed Engl 2007. [DOI: 10.1002/ange.200604802] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Scott DE, Ciulli A, Abell C. Coenzyme biosynthesis: enzyme mechanism, structure and inhibition. Nat Prod Rep 2007; 24:1009-26. [PMID: 17898895 DOI: 10.1039/b703108b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights five key reactions in vitamin biosynthesis and in particular focuses on their mechanisms and inhibition and insights from structural studies. Each of the enzymes has the potential to be a target for novel antimicrobial agents.
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Affiliation(s)
- Duncan E Scott
- University Chemical Laboratory, Lensfield Road, Cambridge, CB2 1EW, UK
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Morgunova E, Illarionov B, Sambaiah T, Haase I, Bacher A, Cushman M, Fischer M, Ladenstein R. Structural and thermodynamic insights into the binding mode of five novel inhibitors of lumazine synthase from Mycobacterium tuberculosis. FEBS J 2006; 273:4790-804. [PMID: 16984393 DOI: 10.1111/j.1742-4658.2006.05481.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Recently published genomic investigations of the human pathogen Mycobacterium tuberculosis have revealed that genes coding the proteins involved in riboflavin biosynthesis are essential for the growth of the organism. Because the enzymes involved in cofactor biosynthesis pathways are not present in humans, they appear to be promising candidates for the development of therapeutic drugs. The substituted purinetrione compounds have demonstrated high affinity and specificity to lumazine synthase, which catalyzes the penultimate step of riboflavin biosynthesis in bacteria and plants. The structure of M. tuberculosis lumazine synthase in complex with five different inhibitor compounds is presented, together with studies of the binding reactions by isothermal titration calorimetry. The inhibitors showed the association constants in the micromolar range. The analysis of the structures demonstrated the specific features of the binding of different inhibitors. The comparison of the structures and binding modes of five different inhibitors allows us to propose the ribitylpurinetrione compounds with C4-C5 alkylphosphate chains as most promising leads for further development of therapeutic drugs against M. tuberculosis.
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Affiliation(s)
- Ekaterina Morgunova
- Karolinska Institutet, NOVUM, Centre for Structural Biochemistry, Huddinge, Sweden.
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Mack M, Grill S. Riboflavin analogs and inhibitors of riboflavin biosynthesis. Appl Microbiol Biotechnol 2006; 71:265-75. [PMID: 16607521 DOI: 10.1007/s00253-006-0421-7] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2006] [Revised: 03/06/2006] [Accepted: 03/06/2006] [Indexed: 11/30/2022]
Abstract
Flavins are active components of many enzymes. In most cases, riboflavin (vitamin B(2)) as a coenzyme represents the catalytic part of the holoenzyme. Riboflavin is an amphiphatic molecule and allows a large variety of different interactions with the enzyme itself and also with the substrate. A great number of active riboflavin analogs can readily be synthesized by chemical methods and, thus, a large number of possible inhibitors for many different enzyme targets is conceivable. As mammalian and especially human biochemistry depends on flavins as well, the target of the inhibiting flavin analog has to be carefully selected to avoid unwanted effects. In addition to flavoproteins, enzymes, which are involved in the biosynthesis of flavins, are possible targets for anti-infectives. Only a few flavin analogs or inhibitors of flavin biosynthesis have been subjected to detailed studies to evaluate their biological activity. Nevertheless, flavin analogs certainly have the potential to serve as basic structures for the development of novel anti-infectives and it is possible that, in the future, the urgent need for new molecules to fight multiresistant microorganisms will be met.
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Affiliation(s)
- Matthias Mack
- Institute for Technical Microbiology, Mannheim University of Applied Sciences, Germany.
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Chen J, Illarionov B, Bacher A, Fischer M, Haase I, Georg G, Ye QZ, Ma Z, Cushman M. A high-throughput screen utilizing the fluorescence of riboflavin for identification of lumazine synthase inhibitors. Anal Biochem 2005; 338:124-30. [PMID: 15707942 DOI: 10.1016/j.ab.2004.11.033] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2004] [Indexed: 11/20/2022]
Abstract
A high-throughput screening method based on the competitive binding of a lumazine synthase inhibitor and riboflavin to the active site of Schizosaccharomyces pombe lumazine synthase was developed. This assay is sensitive, simple, and robust. During assay development, all of the known active inhibitors tested were positively identified. Preliminary high-throughput screening in 384-well format resulted in a Z factor of 0.7. The approach utilizes a thermodynamic assay to bypass the problems associated with the instabilities of both lumazine synthase substrates that complicate the use of a kinetic assay in a high-throughput format, and it removes the time element from the assay, thus simplifying the procedure.
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Affiliation(s)
- Jinhua Chen
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, Purdue University, West Lafayette, IN 47907, USA
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Abstract
The biosynthesis of one riboflavin molecule requires one molecule of GTP and two molecules of ribulose 5-phosphate. The imidazole ring of GTP is hydrolytically opened, yielding a 2,5-diaminopyrimidine that is converted to 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione by a sequence of deamination, side chain reduction, and dephosphorylation. Condensation of 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione with 3,4-dihydroxy-2-butanone 4-phosphate obtained from ribulose 5-phosphate affords 6,7-dimethyl-8-ribityllumazine. Dismutation of the lumazine derivative yields riboflavin and 5-amino-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, which is recycled in the biosynthetic pathway. The enzymes of the riboflavin pathway are potential targets for antibacterial agents.
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Affiliation(s)
- Markus Fischer
- Lehrstuhl für Organische Chemie und Biochemie, Technische Universität München, Lichtenbergstr. 4, D-85747, Garching, Germany.
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Koch M, Breithaupt C, GerhardtHaase S, Weber S, Cushman M, Huber R, Bacher A, Fischer M. Structural basis of charge transfer complex formation by riboflavin bound to 6,7-dimethyl-8-ribityllumazine synthase. ACTA ACUST UNITED AC 2004; 271:3208-14. [PMID: 15265040 DOI: 10.1111/j.1432-1033.2004.04253.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The amino acid residue tryptophan 27 of 6,7-dimethyl-8-ribityllumazine synthase of the yeast Schizosaccharomyces pombe was replaced by tyrosine. The structures of the W27Y mutant protein in complex with riboflavin, the substrate analogue 5-nitroso-6-ribitylamino-2,4(1H,3H)-pyrimidinedione, and the product analogue 6-carboxyethyl-7-oxo-8-ribityllumazine, were determined by X-ray crystallography at resolutions of 2.7-2.8 A. Whereas the indole system of W27 forms a coplanar pi-complex with riboflavin, the corresponding phenyl ring in the W27Y mutant establishes only peripheral contact with the heterocyclic ring system of the bound riboflavin. These findings provide an explanation for the absence of the long wavelength shift in optical absorption spectra of riboflavin bound to the mutant enzyme. The structures of the mutants are important tools for the interpretation of the unusual physical properties of riboflavin in complex with lumazine synthase.
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Affiliation(s)
- Michael Koch
- Abteilung Strukturforschung, Max-Planck-Institut für Biochemie, Martinsried, Germany
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Chapter 6.3 Triazines, tetrazines and fused ring polyaza systems. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/s0959-6380(03)80017-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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