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Smiejkowska N, Oorts L, Van Calster K, De Vooght L, Geens R, Mattelaer HP, Augustyns K, Strelkov SV, Lamprecht D, Temmerman K, Sterckx YGJ, Cappoen D, Cos P. A high-throughput target-based screening approach for the identification and assessment of Mycobacterium tuberculosis mycothione reductase inhibitors. Microbiol Spectr 2024; 12:e0372323. [PMID: 38315026 PMCID: PMC10913476 DOI: 10.1128/spectrum.03723-23] [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: 10/20/2023] [Accepted: 12/21/2023] [Indexed: 02/07/2024] Open
Abstract
The World Health Organization's goal to combat tuberculosis (TB) is hindered by the emergence of anti-microbial resistance, therefore necessitating the exploration of new drug targets. Multidrug regimens are indispensable in TB therapy as they provide synergetic bactericidal effects, shorten treatment duration, and reduce the risk of resistance development. The research within our European RespiriTB consortium explores Mycobacterium tuberculosis energy metabolism to identify new drug candidates that synergize with bedaquiline, with the aim of discovering more efficient combination drug regimens. In this study, we describe the development and validation of a luminescence-coupled, target-based assay for the identification of novel compounds inhibiting Mycobacterium tuberculosis mycothione reductase (MtrMtb), an enzyme with a role in the protection against oxidative stress. Recombinant MtrMtb was employed for the development of a highly sensitive, robust high-throughput screening (HTS) assay by coupling enzyme activity to a bioluminescent readout. Its application in a semi-automated setting resulted in the screening of a diverse library of ~130,000 compounds, from which 19 hits were retained after an assessment of their potency, selectivity, and specificity. The selected hits formed two clusters and four fragment molecules, which were further evaluated in whole-cell and intracellular infection assays. The established HTS discovery pipeline offers an opportunity to deliver novel MtrMtb inhibitors and lays the foundation for future efforts in developing robust biochemical assays for the identification and triaging of inhibitors from high-throughput library screens. IMPORTANCE The growing anti-microbial resistance poses a global public health threat, impeding progress toward eradicating tuberculosis. Despite decades of active research, there is still a dire need for the discovery of drugs with novel modes of action and exploration of combination drug regimens. Within the European RespiriTB consortium, we explore Mycobacterium tuberculosis energy metabolism to identify new drug candidates that synergize with bedaquiline, with the aim of discovering more efficient combination drug regimens. In this study, we present the development of a high-throughput screening pipeline that led to the identification of M. tuberculosis mycothione reductase inhibitors.
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Affiliation(s)
- Natalia Smiejkowska
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
- Laboratory of Medical Biochemistry, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Lauren Oorts
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Kevin Van Calster
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Linda De Vooght
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Rob Geens
- Laboratory of Medical Biochemistry, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Henri-Philippe Mattelaer
- Laboratory of Medicinal Chemistry, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Koen Augustyns
- Laboratory of Medicinal Chemistry, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Sergei V. Strelkov
- Biocrystallography, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, Leuven, Belgium
| | | | | | - Yann G.-J. Sterckx
- Laboratory of Medical Biochemistry, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Davie Cappoen
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
| | - Paul Cos
- Laboratory of Microbiology, Parasitology and Hygiene, Faculty of Pharmaceutical, Biomedical and Veterinary Sciences, University of Antwerp, Wilrijk, Antwerp, Belgium
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2
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Yang J, Xie D, Ma X. Recent Advances in Chemical Synthesis of Amino Sugars. Molecules 2023; 28:4724. [PMID: 37375279 DOI: 10.3390/molecules28124724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/06/2023] [Accepted: 06/07/2023] [Indexed: 06/29/2023] Open
Abstract
Amino sugars are a kind of carbohydrates with one or more hydroxyl groups replaced by an amino group. They play crucial roles in a broad range of biological activities. Over the past few decades, there have been continuing efforts on the stereoselective glycosylation of amino sugars. However, the introduction of glycoside bearing basic nitrogen is challenging using conventional Lewis acid-promoted pathways owing to competitive coordination of the amine to the Lewis acid promoter. Additionally, diastereomeric mixtures of O-glycoside are often produced if aminoglycoside lack a C2 substituent. This review focuses on the updated overview of the way to stereoselective synthesis of 1,2-cis-aminoglycoside. The scope, mechanism, and the applications in the synthesis of complex glycoconjugates for the representative methodologies were also included.
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Affiliation(s)
- Jian Yang
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Demeng Xie
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
| | - Xiaofeng Ma
- Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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Sayer LH, Florence GJ, Smith TK. A biocatalytic approach towards the stereoselective synthesis of protected inositols. REACT CHEM ENG 2017. [DOI: 10.1039/c6re00175k] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Immobilized TbINO1 produces >400 mg of chiral inositol 1-phosphate in a biocatalytic flow process.
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Affiliation(s)
- L. H. Sayer
- Biomedical Science Research Complex
- Schools of Chemistry and Biology
- University of St Andrews
- St Andrews
- UK
| | - G. J. Florence
- Biomedical Science Research Complex
- Schools of Chemistry and Biology
- University of St Andrews
- St Andrews
- UK
| | - T. K. Smith
- Biomedical Science Research Complex
- Schools of Chemistry and Biology
- University of St Andrews
- St Andrews
- UK
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4
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Paritala H, Carroll KS. New targets and inhibitors of mycobacterial sulfur metabolism. Infect Disord Drug Targets 2013; 13:85-115. [PMID: 23808874 PMCID: PMC4332622 DOI: 10.2174/18715265113139990022] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 05/08/2013] [Indexed: 11/22/2022]
Abstract
The identification of new antibacterial targets is urgently needed to address multidrug resistant and latent tuberculosis infection. Sulfur metabolic pathways are essential for survival and the expression of virulence in many pathogenic bacteria, including Mycobacterium tuberculosis. In addition, microbial sulfur metabolic pathways are largely absent in humans and therefore, represent unique targets for therapeutic intervention. In this review, we summarize our current understanding of the enzymes associated with the production of sulfated and reduced sulfur-containing metabolites in Mycobacteria. Small molecule inhibitors of these catalysts represent valuable chemical tools that can be used to investigate the role of sulfur metabolism throughout the Mycobacterial lifecycle and may also represent new leads for drug development. In this light, we also summarize recent progress made in the development of inhibitors of sulfur metabolism enzymes.
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Affiliation(s)
| | - Kate S. Carroll
- Department of Chemistry, The Scripps Research Institute, Jupiter, Florida, 33458, USA
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5
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Nokwequ MG, Nkambule CM, Gammon DW. Armed–disarmed effect on the stability of cysteine thioglucosides. Carbohydr Res 2012; 359:18-23. [DOI: 10.1016/j.carres.2012.06.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Revised: 06/22/2012] [Accepted: 06/30/2012] [Indexed: 11/25/2022]
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McConnell MS, Yu F, Nguyen HM. Nickel-catalyzed α-glycosylation of C(1)-hydroxyl D-myo-inositol: a formal synthesis of mycothiol. Chem Commun (Camb) 2012; 49:4313-5. [PMID: 22992771 DOI: 10.1039/c2cc35823a] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Formal synthesis of mycothiol has been developed via nickel-catalyzed α-glycosylation of the C(1)-hydroxyl group of D-myo-inositols with C(2)-N-substituted benzylideneamino N-phenyl trifluoroacetimidate donors. The pseudo-oligosaccharides were obtained in good yield and with excellent α-selectivity. Removal of the C(2)-N-2-trifluoromethylphenyl-benzylidene group under mild conditions provides a pseudo-disaccharide, completing the formal synthesis of mycothiol.
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7
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Lamprecht DA, Muneri NO, Eastwood H, Naidoo KJ, Strauss E, Jardine A. An enzyme-initiated Smiles rearrangement enables the development of an assay of MshB, the GlcNAc-Ins deacetylase of mycothiol biosynthesis. Org Biomol Chem 2012; 10:5278-88. [PMID: 22678300 DOI: 10.1039/c2ob25429h] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
MshB is the N-acetyl-1-D-myo-inosityl-2-amino-2-deoxy-D-glucopyranoside (GlcNAc-Ins) deacetylase active as one of the enzymes involved in the biosynthesis of mycothiol (MSH), a protective low molecular weight thiol present only in Mycobacterium tuberculosis and other actinomycetes. In this study, structural analogues of GlcNAc-Ins in which the inosityl moiety is replaced by a chromophore were synthesized and evaluated as alternate substrates of MshB, with the goal of identifying a compound that would be useful in high-throughput assays of the enzyme. In an unexpected and surprising finding one of the GlcNAc-Ins analogues is shown to undergo a Smiles rearrangement upon MshB-mediated deacetylation, uncovering a free thiol group. We demonstrate that this chemistry can be exploited for the development of the first continuous assay of MshB activity based on the detection of thiol formation by DTNB (Ellman's reagent); such an assay should be ideally suited for the identification of MshB inhibitors by means of high-throughput screens in microplates.
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Affiliation(s)
- Dirk A Lamprecht
- Department of Biochemistry, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa
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8
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Chung CC, Zulueta MML, Padiyar LT, Hung SC. Desymmetrization of 2,4,5,6-Tetra-O-benzyl-d-myo-inositol for the Synthesis of Mycothiol. Org Lett 2011; 13:5496-9. [DOI: 10.1021/ol202218n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Chuan-Chung Chung
- Genomics Research Center, Academia Sinica, 128 Sec.2 Academia Road, Taipei 115, Taiwan, and Department of Applied Chemistry, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan
| | - Medel Manuel L. Zulueta
- Genomics Research Center, Academia Sinica, 128 Sec.2 Academia Road, Taipei 115, Taiwan, and Department of Applied Chemistry, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan
| | - Laxmansingh T. Padiyar
- Genomics Research Center, Academia Sinica, 128 Sec.2 Academia Road, Taipei 115, Taiwan, and Department of Applied Chemistry, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan
| | - Shang-Cheng Hung
- Genomics Research Center, Academia Sinica, 128 Sec.2 Academia Road, Taipei 115, Taiwan, and Department of Applied Chemistry, National Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu 300, Taiwan
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9
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Nkambule CM, Kwezi NW, Kinfe HH, Nokwequ MG, Gammon DW, Oscarson S, Karlsson E. Efficient regioselective protection of myo-inositol via facile protecting group migration. Tetrahedron 2011. [DOI: 10.1016/j.tet.2010.11.063] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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10
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Ajayi K, Thakur VV, Lapo RC, Knapp S. Intramolecular alpha-glucosaminidation: synthesis of mycothiol. Org Lett 2010; 12:2630-3. [PMID: 20443569 DOI: 10.1021/ol1008334] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A protected cyclitol aglycon was tethered to an (N-arylsulfonyl)glucosamine donor by a methylene linker; the exclusively alpha-selective intramolecular glycosylation reaction was then initiated by electrophilic activation of the thioglycoside donor portion. Further transformations of the glycosylation product to give the M. tuberculosis detoxifier mycothiol and its oxidized congener, the disulfide mycothione, are detailed.
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Affiliation(s)
- Kehinde Ajayi
- Department of Chemistry and Chemical Biology, Rutgers-The State University of New Jersey, 610 Taylor Road, Piscataway, New Jersey 08854, USA
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11
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Gammon DW, Steenkamp DJ, Mavumengwana V, Marakalala MJ, Mudzunga TT, Hunter R, Munyololo M. Conjugates of plumbagin and phenyl-2-amino-1-thioglucoside inhibit MshB, a deacetylase involved in the biosynthesis of mycothiol. Bioorg Med Chem 2010; 18:2501-14. [DOI: 10.1016/j.bmc.2010.02.049] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2009] [Revised: 02/21/2010] [Accepted: 02/23/2010] [Indexed: 11/26/2022]
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12
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Hamilton CJ, Finlay RMJ, Stewart MJG, Bonner A. Mycothiol disulfide reductase: a continuous assay for slow time-dependent inhibitors. Anal Biochem 2009; 388:91-6. [PMID: 19233116 DOI: 10.1016/j.ab.2009.02.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2008] [Revised: 02/10/2009] [Accepted: 02/11/2009] [Indexed: 11/30/2022]
Abstract
Mycothiol (MSH) is the principal low-molecular-weight thiol, unique to mycobacteria and other actinomycetes, that performs a role analogous to glutathione found in other organisms. MSH plays a key role in oxidative stress management and is oxidized to the dimeric mycothiol disulfide (MSSM) in the process. NADPH-dependent mycothiol disulfide reductase (Mtr) helps to maintain an intracellular reducing environment by reducing MSSM back to MSH. Mtr inhibition studies are currently impaired by limited availability of MSSM. Substrate demands are particularly high in time-dependent inhibition assays. Here we report an assay that chemically recycles a mixed disulfide substrate analogue in situ, thereby greatly reducing the substrate quantities needed for such assays. This has enabled the development of a continuous assay where linear reaction rates can be maintained for 40 min or longer using minimal substrate concentrations (5 microM versus a substrate K(m) value of 268 microM). In this manner, substrate requirements are reduced by orders of magnitude. Characterization of a novel time-dependent inhibitor, 2-(5-bromo-2-methoxyphenyl)acrylonitrile, is also demonstrated using these procedures.
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Affiliation(s)
- Chris J Hamilton
- School of Chemical Sciences and Pharmacy, University of East Anglia, Norwich, Norfolk NR47TJ, UK.
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13
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Biosynthesis and functions of mycothiol, the unique protective thiol of Actinobacteria. Microbiol Mol Biol Rev 2008; 72:471-94. [PMID: 18772286 DOI: 10.1128/mmbr.00008-08] [Citation(s) in RCA: 262] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mycothiol (MSH; AcCys-GlcN-Ins) is the major thiol found in Actinobacteria and has many of the functions of glutathione, which is the dominant thiol in other bacteria and eukaryotes but is absent in Actinobacteria. MSH functions as a protected reserve of cysteine and in the detoxification of alkylating agents, reactive oxygen and nitrogen species, and antibiotics. MSH also acts as a thiol buffer which is important in maintaining the highly reducing environment within the cell and protecting against disulfide stress. The pathway of MSH biosynthesis involves production of GlcNAc-Ins-P by MSH glycosyltransferase (MshA), dephosphorylation by the MSH phosphatase MshA2 (not yet identified), deacetylation by MshB to produce GlcN-Ins, linkage to Cys by the MSH ligase MshC, and acetylation by MSH synthase (MshD), yielding MSH. Studies of MSH mutants have shown that the MSH glycosyltransferase MshA and the MSH ligase MshC are required for MSH production, whereas mutants in the MSH deacetylase MshB and the acetyltransferase (MSH synthase) MshD produce some MSH and/or a closely related thiol. Current evidence indicates that MSH biosynthesis is controlled by transcriptional regulation mediated by sigma(B) and sigma(R) in Streptomyces coelicolor. Identified enzymes of MSH metabolism include mycothione reductase (disulfide reductase; Mtr), the S-nitrosomycothiol reductase MscR, the MSH S-conjugate amidase Mca, and an MSH-dependent maleylpyruvate isomerase. Mca cleaves MSH S-conjugates to generate mercapturic acids (AcCySR), excreted from the cell, and GlcN-Ins, used for resynthesis of MSH. The phenotypes of MSH-deficient mutants indicate the occurrence of one or more MSH-dependent S-transferases, peroxidases, and mycoredoxins, which are important targets for future studies. Current evidence suggests that several MSH biosynthetic and metabolic enzymes are potential targets for drugs against tuberculosis. The functions of MSH in antibiotic-producing streptomycetes and in bioremediation are areas for future study.
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Newton GL, Fahey RC. An N-acyl homolog of mycothiol is produced in marine actinomycetes. Arch Microbiol 2008; 190:547-57. [PMID: 18629474 PMCID: PMC2574923 DOI: 10.1007/s00203-008-0405-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2008] [Revised: 06/13/2008] [Accepted: 06/25/2008] [Indexed: 10/21/2022]
Abstract
Marine actinomycetes have generated much recent interest as a potentially valuable source of novel antibiotics. Like terrestrial actinomycetes the marine actinomycetes are shown here to produce mycothiol as their protective thiol. However, a novel thiol, U25, was produced by MAR2 strain CNQ703 upon progression into stationary phase when secondary metabolite production occurred and became the dominant thiol. MSH and U25 were maintained in a reduced state during early stationary phase, but become significantly oxidized after 10 days in culture. Isolation and structural analysis of the monobromobimane derivative identified U25 as a homolog of mycothiol in which the acetyl group attached to the nitrogen of cysteine is replaced by a propionyl residue. This N-propionyl-desacetyl-mycothiol was present in 13 of the 17 strains of marine actinomycetes examined, including five strains of Salinispora and representatives of the MAR2, MAR3, MAR4 and MAR6 groups. Mycothiol and its precursor, the pseudodisaccharide 1-O-(2-amino-2-deoxy-alpha-D-glucopyranosyl)-D-myo-inositol, were found in all strains. High levels of mycothiol S-conjugate amidase activity, a key enzyme in mycothiol-dependent detoxification, were found in most strains. The results demonstrate that major thiol/disulfide changes accompany secondary metabolite production and suggest that mycothiol-dependent detoxification is important at this developmental stage.
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Affiliation(s)
- Gerald L. Newton
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA e-mail: fax: 858-5344864
| | - Robert C. Fahey
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA e-mail: fax: 858-5344864
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15
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Jothivasan VK, Hamilton CJ. Mycothiol: synthesis, biosynthesis and biological functions of the major low molecular weight thiol in actinomycetes. Nat Prod Rep 2008; 25:1091-117. [PMID: 19030604 DOI: 10.1039/b616489g] [Citation(s) in RCA: 117] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Actinomycetes produce mycothiol as their major low molecular weight thiol, which parallels the functions of glutathione found in prokaryotes and most Gram-negative bacteria. This review covers progress that has so far been made in terms of its distribution, biosynthesis and metabolic functions, as well as chemical syntheses of mycothiol and alternative substrates and inhibitors of mycothiol biosynthesis and mycothiol-dependent enzymes. 152 references are cited.
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Stewart MJG, Jothivasan VK, Rowan AS, Wagg J, Hamilton CJ. Mycothiol disulfide reductase: solid phase synthesis and evaluation of alternative substrate analogues. Org Biomol Chem 2008; 6:385-90. [DOI: 10.1039/b716380k] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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17
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Slättegård R, Gammon DW, Oscarson S. Synthesis of fused bicyclic thioglycosides of N-acylated glucosamine as analogues of mycothiol. Carbohydr Res 2007; 342:1943-6. [PMID: 17509548 DOI: 10.1016/j.carres.2007.04.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 04/19/2007] [Accepted: 04/22/2007] [Indexed: 11/29/2022]
Abstract
The synthesis of a fused bicyclic thioglycoside analogue of mycothiol, (3R)-3-acetylamino-4-one-6,7-dihydro-(1',2'-dideoxy-beta-D-glucopyranoso)[2',1'-f]-1,5-thiazepane (5), is reported. Treatment of phthalimido-protected peracetylated glucosamine with N-acetyl-cysteine and boron trifluoride-etherate gave the beta-linked thioglycoside, which was deprotected and cyclized, using HOBt and EDCl to form the lactam and giving the target structure. This mycothiol mimic and its tri-O-acetate will be investigated as potential inhibitors of enzymes involved in the biosynthesis of mycothiol. The protected derivative also has the potential to be an alpha-selective N-cysteinyl glucosamine donor; however, initial glycosylation attempts failed due to the apparent stability of the fused bicyclic system.
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Affiliation(s)
- Rikard Slättegård
- Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, S-106 91 Stockholm, Sweden
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18
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Hand CE, Auzanneau FI, Honek JF. Conformational analyses of mycothiol, a critical intracellular glycothiol in Mycobacteria. Carbohydr Res 2006; 341:1164-73. [PMID: 16630596 DOI: 10.1016/j.carres.2006.03.020] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2005] [Revised: 03/06/2006] [Accepted: 03/11/2006] [Indexed: 11/21/2022]
Abstract
Intracellular thiols are essential biomolecules, which play several critical roles in living organisms including controlling intracellular redox potential and acting as cofactors for several vital detoxification enzymes including S-transferases and formaldehyde dehydrogenases. The tripeptide gamma-L-glutamyl-L-cysteinylglycine, more commonly known as glutathione, is well known as the major intracellular thiol in eukaryotes and in some bacteria. However, glutathione is absent in the Actinomycetales bacteria such as Mycobacteria and Streptomyces and is believed to be replaced by 1-D-myo-inosityl-2-(N-acetyl-L-cysteinyl)amido-2-deoxy-alpha-D-glucopyranoside, mycothiol, in these organisms. Although much is known about the chemistry and biochemistry of glutathione, currently much less is known concerning mycothiol and its properties. The structure of mycothiol is composed of a glycoside linkage between myo-inositol and D-glucosamine with an N-acetyl-L-cysteine linked to the 2'-amino group of the d-glucosamine moiety. Mycothiol is currently of intense interest due to its essential role in the cellular physiology of Mycobacteria, such as Mycobacterium tuberculosis, and its possible role in antimycobacterial drug resistance. A detailed investigation of its chemistry is therefore essential in ameliorating our knowledge of this key glycothiol, and in shedding additional light on its biochemical role in these pathogenic organisms. This report presents a detailed conformational analysis of mycothiol utilizing a variety of force fields and stochastic search protocols. Cluster analyses of energetically low lying conformations have indicated the presence of several key conformations that are populated in the gas phase and with implicit water solvation. These conformations are compared to recent NMR studies on a derivative of mycothiol. This information should be an important contribution to our basic understanding of the chemistry of this glycothiol and critical in the design of novel inhibitors of pathogen enzymes that require it.
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Affiliation(s)
- Christine E Hand
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, Canada N2L 3G1
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Witczak ZJ, Culhane JM. Thiosugars: new perspectives regarding availability and potential biochemical and medicinal applications. Appl Microbiol Biotechnol 2005; 69:237-44. [PMID: 16240117 DOI: 10.1007/s00253-005-0156-x] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Revised: 08/22/2005] [Accepted: 08/29/2005] [Indexed: 10/25/2022]
Abstract
Thiosugars, containing a sulfur atom as heteroatom or a disaccharide linked via a sulfur bridge, possess unique physicochemical properties such as water solubility, which differs from conventional functionalized monosaccharides. The differences in biological activities between thiosugars and their oxygen analogs depend on geometric, conformational, and flexibility differences. They depend also on their electronic differences, the sulfide function being less electronegative and more polarizable than the ethereal moiety. Many functionalized thiosugars occur naturally and are potential targets for the development of carbohydrate-based therapeutics. Among the few new examples of the potential new targets are salacinol and kotalanol, tagetitoxin, thiolactomycin and analogues, mycothiol and analogues, and S-nitrosothiols. These new developments and representative examples of functionalized thiosugar prototypes as potential new targets are presented in this mini review.
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Affiliation(s)
- Zbigniew J Witczak
- Department of Pharmaceutical Sciences, Nesbitt School of Pharmacy, Wilkes University, Wilkes-Barre, PA 18766, USA.
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Hand CE, Honek JF. Biological chemistry of naturally occurring thiols of microbial and marine origin. JOURNAL OF NATURAL PRODUCTS 2005; 68:293-308. [PMID: 15730267 DOI: 10.1021/np049685x] [Citation(s) in RCA: 117] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The presence of thiols in living systems is critical for the maintenance of cellular redox potentials and protein thiol-disulfide ratios, as well as for the protection of cells from reactive oxygen species. In addition to the well-studied tripeptide glutathione (gamma-Glu-Cys-Gly), a number of compounds have been identified that contribute to these essential cellular roles. This review provides a survey of the chemistry and biochemistry of several critically important and naturally occurring intracellular thiols such as coenzyme M, trypanothione, mycothiol, ergothioneine, and the ovothiols. Coenzyme M is a key thiol required for methane production in methogenic bacteria. Trypanothione and mycothiol are very important to the biochemistry of a number of human pathogens, and the enzymes utilizing these thiols have been recognized as important novel drug targets. Ergothioneine, although synthesized by fungi and the Actinomycetales bacteria, is present at significant physiological levels in humans and may contribute to single electron redox reactions in cells. The ovothiols appear to function as important modulators of reactive oxygen toxicity and appear to serve as small molecule mimics of glutathione peroxidase, a key enzyme in the detoxification of reactive oxygen species.
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Affiliation(s)
- Christine E Hand
- Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada N2L 3G1
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Abstract
[reaction: see text] The first total synthesis of mycothiol and mycothiol disulfide was achieved by linking D-2,3,4,5,6-penta-O-acetyl-myo-inositol, O-(3,4,6-tri-O-acetyl)-2-azido-2-deoxy-alpha,beta-D-glucopyranosyl) trichloroacetimidate, and N,S-diacetyl-L-cysteine and deprotecting peracetylated mycothiol. The first full spectral characterization is reported for underivatized mycothiol. The structure of mycothiol was confirmed by spectral analysis of the known bimane derivative.
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Affiliation(s)
- Sungwon Lee
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, and Center for Biocatalysis and Bioprocessing, The University of Iowa, Iowa City, Iowa 52242, USA
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Steenkamp DJ, Vogt RN. Preparation and utilization of a reagent for the isolation and purification of low-molecular-mass thiols. Anal Biochem 2004; 325:21-7. [PMID: 14715280 DOI: 10.1016/j.ab.2003.10.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Problems inherent in the isolation of thiols from natural sources, such as oxidation, undesirable addition reactions, and low concentration of thiol species in cell-free extracts, can be circumvented by reversible derivatization to a less labile form which can be concentrated selectively. These objectives are realized by converting thiols to heterodisulfides in which the thiol partner is an apolar thiol with strong affinity for hydrophobic stationary phases. When reacted with 2-S-(2(')-thiopyridyl)-6-hydroxynaphthyldisulfide at pH<5, where most thiol species are relatively stable to atmospheric oxidation, mixed disulfides with 2-mercapto-6-hydroxynaphthalene as the apolar partner are obtained in good yield and can be concentrated onto a hydrophobic stationary phase. Such heterodisulfides exhibit excellent chromatographic properties when separated on reversed-phase media and the derivatization reaction can, therefore, be conveniently monitored. Following their isolation as the heterodisulfides the thiol species of interest are recovered by reduction and facile separation from the apolar 2-mercapto-6-hydroxynaphthalene partner.
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Affiliation(s)
- Daniel J Steenkamp
- Division of Chemical Pathology, Faculty of Health Sciences, University of Cape Town, Observatory 7935, Cape Town, South Africa.
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Gammon DW, Hunter R, Steenkamp DJ, Mudzunga TT. Synthesis of 2-deoxy-2-C-alkylglucosides of myo-inositol as possible inhibitors of a N-deacetylase enzyme in the biosynthesis of mycothiol. Bioorg Med Chem Lett 2003; 13:2045-9. [PMID: 12781192 DOI: 10.1016/s0960-894x(03)00157-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Two new analogues of 1-D-1-O-(2-acetamido-2-deoxy-alpha-D-glucopyranosyl)-myo-inositol, a biosynthetic intermediate in the production of mycothiol in the Mycobacteria have been synthesized. Both the 2-deoxy-2-C-(2'-hydroxypropyl)-D-glucoside 5, and the 2-deoxy-2-C-(2'-oxopropyl)-D-glucoside 6, are derived from fully benzylated 1-D-1-O-(2-C-allyl-2-deoxy)-D-glucopyranosyl)-myo-inositol 20, readily assembled via a protected 2-C-allyl-2-deoxyglucosyl fluoride. Both 5 and 6 inhibit the incorporation of [3H]inositol by whole cells of Mycobacterium smegmatis into a number of metabolites which contain inositol.
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Affiliation(s)
- David W Gammon
- Department of Chemistry, University of Cape Town, 7701, Rondebosch, South Africa
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Nicholas GM, Eckman LL, Kovác P, Otero-Quintero S, Bewley CA. Synthesis of 1-D- and 1-L-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside establishes substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase. Bioorg Med Chem 2003; 11:2641-7. [PMID: 12757730 DOI: 10.1016/s0968-0896(03)00154-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Mycothiol (MSH, 1-D-myo-inosityl 2-(N-acetyl-L-cysteinyl)amido-2-deoxy-alpha-D-glucopyranoside) is the principal low molecular weight thiol in actinomycetes. The enzyme 1-D-myo-inosityl 2-N-acetamido-2-deoxy-alpha-D-glucopyranoside deacetylase (AcGI deacetylase) is involved in the biosynthesis of MSH and forms the free amine 1-D-myo-inosityl 2-amino-2-deoxy-alpha-D-glucopyranoside, which is used in the third of four steps of MSH biosynthesis. Here, we report the synthesis of two isomers of AcGI, which contain either 1-L-myo-inositol or 1-D-myo-inositol. These synthetic products were used to investigate substrate specificity of the Mycobacterium tuberculosis enzyme AcGI deacetylase.
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Affiliation(s)
- Gillian M Nicholas
- Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0820, USA
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Abstract
[structure: see text] The synthesis of a simplified thioglycosidic analogue (2) of mycothiol (1) is described. Evaluation of 2 against mycothiol S-conjugate amidase from Mycobacterium tuberculosis reveals good specific activity (7500 nmol min(-)(1) mg-protein(-)(1), vs 14 200 for 1), indicating that 2 can serve as a starting point for antitubercular drug design.
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Affiliation(s)
- Spencer Knapp
- Department of Chemistry and Chemical Biology, Rutgers The State University of New Jersey, 610 Taylor Rd., Piscataway, New Jersey 08854-8087, USA.
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