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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: 10] [Impact Index Per Article: 2.0] [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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2
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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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3
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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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4
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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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5
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Sousa CA, Rodríguez-Borges JE, Garcia-Mera X. Synthesis and N-functionalization of isoxazolidines: a new approach to nucleoside analogues. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.06.076] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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6
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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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7
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Talukdar A, Zhao Y, Lv W, Bacher A, Illarionov B, Fischer M, Cushman M. O-Nucleoside, S-nucleoside, and N-nucleoside probes of lumazine synthase and riboflavin synthase. J Org Chem 2012; 77:6239-61. [PMID: 22780198 PMCID: PMC3444172 DOI: 10.1021/jo3010364] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Lumazine synthase catalyzes the penultimate step in the biosynthesis of riboflavin, while riboflavin synthase catalyzes the last step. O-Nucleoside, S-nucleoside, and N-nucleoside analogues of hypothetical lumazine biosynthetic intermediates have been synthesized in order to obtain structure and mechanism probes of these two enzymes, as well as inhibitors of potential value as antibiotics. Methods were devised for the selective cleavage of benzyl protecting groups in the presence of other easily reduced functionality by controlled hydrogenolysis over Lindlar catalyst. The deprotection reaction was performed in the presence of other reactive functionality including nitro groups, alkenes, and halogens. The target compounds were tested as inhibitors of lumazine synthase and riboflavin synthase obtained from a variety of microorganisms. In general, the S-nucleosides and N-nucleosides were more potent than the corresponding O-nucleosides as lumazine synthase and riboflavin synthase inhibitors, while the C-nucleosides were the least potent. A series of molecular dynamics simulations followed by free energy calculations using the Poisson-Boltzmann/surface area (MM-PBSA) method were carried out in order to rationalize the results of ligand binding to lumazine synthase, and the results provide insight into the dynamics of ligand binding as well as the molecular forces stabilizing the intermediates in the enzyme-catalyzed reaction.
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Affiliation(s)
- Arindam Talukdar
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, and The Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Yujie Zhao
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, and The Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Wei Lv
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, and The Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, 47907, USA
| | - Adelbert Bacher
- Institute of Biochemistry and Food Chemistry, Food Chemistry Division, University of Hamburg, D-20146 Hamburg, Germany
| | - Boris Illarionov
- Institute of Biochemistry and Food Chemistry, Food Chemistry Division, University of Hamburg, D-20146 Hamburg, Germany
| | - Markus Fischer
- Institute of Biochemistry and Food Chemistry, Food Chemistry Division, University of Hamburg, D-20146 Hamburg, Germany
| | - Mark Cushman
- Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, and The Purdue Center for Cancer Research, Purdue University, West Lafayette, Indiana, 47907, USA
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8
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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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9
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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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10
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Enderlin G, Taillefumier C, Didierjean C, Chapleur Y. An Efficient Route to Acyclic C-Nucleosides and Fused-Ring Analogues of Uridine from exo-Glycals. J Org Chem 2009; 74:8388-91. [DOI: 10.1021/jo901604w] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Gérald Enderlin
- UMR SRSMC 7565 Nancy-Université CNRS, Groupe SUCRES, BP 239, F-54506 Vandoeuvre, France
| | - Claude Taillefumier
- UMR SRSMC 7565 Nancy-Université CNRS, Groupe SUCRES, BP 239, F-54506 Vandoeuvre, France
- UMR SESSIB, Université Blaise Pascal Clermont II, CNRS, F-63000 Clermont-Ferrand, France
| | - Claude Didierjean
- UMR LCM3B 7036, Nancy-Université CNRS, BP 239, F-54506 Vandoeuvre, France
| | - Yves Chapleur
- UMR SRSMC 7565 Nancy-Université CNRS, Groupe SUCRES, BP 239, F-54506 Vandoeuvre, France
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11
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Talukdar A, Breen M, Bacher A, Illarionov B, Fischer M, Georg G, Ye QZ, Cushman M. Discovery and development of a small molecule library with lumazine synthase inhibitory activity. J Org Chem 2009; 74:5123-34. [PMID: 19552377 PMCID: PMC2760403 DOI: 10.1021/jo900238q] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
(E)-5-Nitro-6-(2-hydroxystyryl)pyrimidine-2,4(1H,3H)-dione (9) was identified as a novel inhibitor of Schizosaccharomyces pombe lumazine synthase by high-throughput screening of a 100000 compound library. The K(i) of 9 vs Mycobacterium tuberculosis lumazine synthase was 95 microM. Compound 9 is a structural analogue of the lumazine synthase substrate 5-amino-6-(d-ribitylamino)-2,4-(1H,3H)pyrimidinedione (1). This indicates that the ribitylamino side chain of the substrate is not essential for binding to the enzyme. Optimization of the enzyme inhibitory activity through systematic structure modification of the lead compound 9 led to (E)-5-nitro-6-(4-nitrostyryl)pyrimidine-2,4(1H,3H)-dione (26), which has a K(i) of 3.7 microM vs M. tuberculosis lumazine synthase.
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Affiliation(s)
- Arindam Talukdar
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, and The Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907
| | - Megan Breen
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, and The Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907
| | | | - Boris Illarionov
- Institute of Food Chemistry, University of Hamburg, D-20146 Hamburg, Germany
| | - Markus Fischer
- Institute of Food Chemistry, University of Hamburg, D-20146 Hamburg, Germany
| | - Gunda Georg
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Qi-Zhuang Ye
- Department of Medicinal Chemistry, University of Kansas, Lawrence, Kansas 66047
| | - Mark Cushman
- Department of Medicinal Chemistry and Molecular Pharmacology, School of Pharmacy and Pharmaceutical Sciences, and The Purdue Cancer Center, Purdue University, West Lafayette, Indiana 47907
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12
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13
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Gazivoda T, Krištafor S, Cetina M, Nagl A, Raić-Malić S. Synthesis and structural studies of C-5 aryl- and C-6 alkyl-substituted pyrimidine derivatives. Struct Chem 2008. [DOI: 10.1007/s11224-008-9302-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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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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15
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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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16
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Romeo G, Iannazzo D, Piperno A, Romeo R, Saglimbeni M, Chiacchio MA, Balestrieri E, Macchi B, Mastino A. Synthesis and biological evaluation of phosphonated dihydroisoxazole nucleosides. Bioorg Med Chem 2006; 14:3818-24. [PMID: 16480883 DOI: 10.1016/j.bmc.2006.01.028] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2005] [Revised: 01/11/2006] [Accepted: 01/17/2006] [Indexed: 10/25/2022]
Abstract
Phosphonated isoxazolinyl nucleosides have been prepared via 1,3-dipolar cycloaddition reaction of nitrile oxides with corresponding vinyl or allyl nucleobases for antiviral studies. The cytotoxicity, the anti-HSV activity and the RT-inhibitory activity of the obtained compounds were evaluated and compared with those of AZT and diethyl{(1'SR,4'RS)-1'-[[(5-methyl-2,4-dioxo-3,4-dihydropyrimidin-1(2H)-yl)]-3'-methyl-2'-oxa-3'-azacyclopent-4'-yl]}methylphosphonate, a saturated phosphonated dihydroisoxazole nucleoside analogue.
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Affiliation(s)
- Giovanni Romeo
- Dipartimento Farmaco-Chimico, Università di Messina, Via SS. Annunziata, Messina 98168, Italy.
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17
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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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18
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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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