scholarly journals Total Synthesis of a Mycolic Acid from Mycobacterium tuberculosis

2020 ◽  
Vol 132 (19) ◽  
pp. 7625-7630
Author(s):  
Nabil Tahiri ◽  
Peter Fodran ◽  
Dhineshkumar Jayaraman ◽  
Jeffrey Buter ◽  
Martin D. Witte ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Total Synthesis ◽  
Mycolic Acid

scholarly journals Total Synthesis of a Mycolic Acid from Mycobacterium tuberculosis

2020 ◽  
Vol 59 (19) ◽  
pp. 7555-7560 ◽  
Author(s):  
Nabil Tahiri ◽  
Peter Fodran ◽  
Dhineshkumar Jayaraman ◽  
Jeffrey Buter ◽  
Martin D. Witte ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Total Synthesis ◽  
Mycolic Acid

Kinase Targets for Mycolic Acid Biosynthesis in Mycobacterium tuberculosis

2019 ◽  
Vol 12 (1) ◽  
pp. 27-49 ◽  
Author(s):  
Shahinda S.R. Alsayed ◽  
Chau C. Beh ◽  
Neil R. Foster ◽  
Alan D. Payne ◽  
Yu Yu ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Enzymatic Activity ◽  
Bacterial Pathogen ◽  
Building Blocks ◽  
Mycolic Acid ◽  
Adaptive Responses ◽  
Mycolic Acids ◽  
Hydroxylated Fatty Acids

Background:Mycolic acids (MAs) are the characteristic, integral building blocks for the mycomembrane belonging to the insidious bacterial pathogen Mycobacterium tuberculosis (M.tb). These C60-C90 long α-alkyl-β-hydroxylated fatty acids provide protection to the tubercle bacilli against the outside threats, thus allowing its survival, virulence and resistance to the current antibacterial agents. In the post-genomic era, progress has been made towards understanding the crucial enzymatic machineries involved in the biosynthesis of MAs in M.tb. However, gaps still remain in the exact role of the phosphorylation and dephosphorylation of regulatory mechanisms within these systems. To date, a total of 11 serine-threonine protein kinases (STPKs) are found in M.tb. Most enzymes implicated in the MAs synthesis were found to be phosphorylated in vitro and/or in vivo. For instance, phosphorylation of KasA, KasB, mtFabH, InhA, MabA, and FadD32 downregulated their enzymatic activity, while phosphorylation of VirS increased its enzymatic activity. These observations suggest that the kinases and phosphatases system could play a role in M.tb adaptive responses and survival mechanisms in the human host. As the mycobacterial STPKs do not share a high sequence homology to the human’s, there have been some early drug discovery efforts towards developing potent and selective inhibitors.Objective:Recent updates to the kinases and phosphatases involved in the regulation of MAs biosynthesis will be presented in this mini-review, including their known small molecule inhibitors.Conclusion:Mycobacterial kinases and phosphatases involved in the MAs regulation may serve as a useful avenue for antitubercular therapy.

scholarly journals Total synthesis, stereochemical elucidation and biological evaluation of Ac2SGL; a 1,3-methyl branched sulfoglycolipid from Mycobacterium tuberculosis

2013 ◽  
Vol 4 (2) ◽  
pp. 709-716 ◽  
Author(s):  
Danny Geerdink ◽  
Bjorn ter Horst ◽  
Marco Lepore ◽  
Lucia Mori ◽  
Germain Puzo ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Total Synthesis ◽  
Biological Evaluation

scholarly journals Resistance against Membrane-Inserting MmpL3 Inhibitor through Upregulation of MmpL5 in Mycobacterium tuberculosis

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Ming Li ◽  
Samuel Agyei Nyantakyi ◽  
Mei-Lin Go ◽  
Thomas Dick
Keyword(s):  
Antibacterial Activity ◽  
Mycobacterium Tuberculosis ◽  
Mouse Model ◽  
Mannich Base ◽  
Efflux Pump ◽  
Transcriptional Repressor ◽  
Mannich Bases ◽  
Mycolic Acid ◽  
Low Level ◽  
Level Resistance

ABSTRACT Spiroketal indolyl Mannich bases (SIMBs) present a novel class of membrane-inserting antimycobacterials with efficacy in a tuberculosis mouse model. SIMBs exert their antibacterial activity by two mechanisms. The indolyl Mannich base scaffold causes permeabilization of bacteria, and the spiroketal moiety contributes to inhibition of the mycolic acid transporter MmpL3. Here, we show that low-level resistance to SIMBs arises by mutations in the transcriptional repressor MmpR5, resulting in upregulation of the efflux pump MmpL5.

scholarly journals Stereocontrolled Total Synthesis of Muraymycin D1 Having a Dual Mode of Action against Mycobacterium tuberculosis

2016 ◽  
Vol 138 (39) ◽  
pp. 12975-12980 ◽  
Author(s):  
Katsuhiko Mitachi ◽  
Bilal A. Aleiwi ◽  
Christopher M. Schneider ◽  
Shajila Siricilla ◽  
Michio Kurosu
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Total Synthesis ◽  
Mode Of Action ◽  
Dual Mode

scholarly journals Redundant Function of cmaA2 and mmaA2 in Mycobacterium tuberculosis cis Cyclopropanation of Oxygenated Mycolates

2010 ◽  
Vol 192 (14) ◽  
pp. 3661-3668 ◽  
Author(s):  
Daniel Barkan ◽  
Vivek Rao ◽  
George D. Sukenick ◽  
Michael S. Glickman
Keyword(s):  
Fatty Acids ◽  
Mycobacterium Tuberculosis ◽  
Genetic Analysis ◽  
Biosynthetic Pathway ◽  
Cell Envelope ◽  
Mycolic Acid ◽  
Acid Modification ◽  
Mycolic Acids ◽  
Powerful Approach ◽  
Long Chain

ABSTRACT The Mycobacterium tuberculosis cell envelope contains a wide variety of lipids and glycolipids, including mycolic acids, long-chain branched fatty acids that are decorated by cyclopropane rings. Genetic analysis of the mycolate methyltransferase family has been a powerful approach to assign functions to each of these enzymes but has failed to reveal the origin of cis cyclopropanation of the oxygenated mycolates. Here we examine potential redundancy between mycolic acid methyltransferases by generating and analyzing M. tuberculosis strains lacking mmaA2 and cmaA2, mmaA2 and cmaA1, or mmaA1 alone. M. tuberculosis lacking both cmaA2 and mmaA2 cannot cis cyclopropanate methoxymycolates or ketomycolates, phenotypes not shared by the mmaA2 and cmaA2 single mutants. In contrast, a combined loss of cmaA1 and mmaA2 had no effect on mycolic acid modification compared to results with a loss of mmaA2 alone. Deletion of mmaA1 from M. tuberculosis abolishes trans cyclopropanation without accumulation of trans-unsaturated oxygenated mycolates, placing MmaA1 in the biosynthetic pathway for trans-cyclopropanated oxygenated mycolates before CmaA2. These results define new functions for the mycolic acid methyltransferases of M. tuberculosis and indicate a substantial redundancy of function for MmaA2 and CmaA2, the latter of which can function as both a cis and trans cyclopropane synthase for the oxygenated mycolates.

scholarly journals ethA, inhA, and katG Loci of Ethionamide-Resistant Clinical Mycobacterium tuberculosis Isolates

2003 ◽  
Vol 47 (12) ◽  
pp. 3799-3805 ◽  
Author(s):  
Glenn P. Morlock ◽  
Beverly Metchock ◽  
David Sikes ◽  
Jack T. Crawford ◽  
Robert C. Cooksey
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Structural Gene ◽  
Single Point ◽  
Resistance Mechanism ◽  
Structural Analog ◽  
Mycolic Acid ◽  
Single Point Mutation ◽  
Structural Genes ◽  
Resistance Mutations ◽  
Catalase Peroxidase

ABSTRACT Ethionamide (ETH) is a structural analog of the antituberculosis drug isoniazid (INH). Both of these drugs target InhA, an enzyme involved in mycolic acid biosynthesis. INH requires catalase-peroxidase (KatG) activation, and mutations in katG are a major INH resistance mechanism. Recently an enzyme (EthA) capable of activating ETH has been identified. We sequenced the entire ethA structural gene of 41 ETH-resistant Mycobacterium tuberculosis isolates. We also sequenced two regions of inhA and all or part of katG. The MICs of ETH and INH were determined in order to associate the mutations identified with a resistance phenotype. Fifteen isolates were found to possess ethA mutations, for all of which the ETH MICs were ≥50 μg/ml. The ethA mutations were all different, previously unreported, and distributed throughout the gene. In eight of the isolates, a missense mutation in the inhA structural gene occurred. The ETH MICs for seven of the InhA mutants were ≥100 μg/ml, and these isolates were also resistant to ≥8 μg of INH per ml. Only a single point mutation in the inhA promoter was identified in 14 isolates. A katG mutation occurred in 15 isolates, for which the INH MICs for all but 1 were ≥32 μg/ml. As expected, we found no association between katG mutation and the level of ETH resistance. Mutations within the ethA and inhA structural genes were associated with relatively high levels of ETH resistance. Approximately 76% of isolates resistant to ≥50 μg of ETH per ml had such mutations.

scholarly journals Single Nucleotide Polymorphisms in Genes Associated with Isoniazid Resistance in Mycobacterium tuberculosis

2003 ◽  
Vol 47 (4) ◽  
pp. 1241-1250 ◽  
Author(s):  
Srinivas V. Ramaswamy ◽  
Robert Reich ◽  
Shu-Jun Dou ◽  
Linda Jasperse ◽  
Xi Pan ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Single Nucleotide Polymorphisms ◽  
Molecular Genetic ◽  
Mycolic Acid ◽  
Genetic Group ◽  
Clinical Isolates ◽  
Central Component ◽  
Polymorphism Analysis ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide

ABSTRACT Isoniazid (INH) is a central component of drug regimens used worldwide to treat tuberculosis. Previous studies have identified resistance-associated mutations in katG, inhA, kasA, ndh, and the oxyR-ahpC intergenic region. DNA microarray-based experiments have shown that INH induces several genes in Mycobacterium tuberculosis that encode proteins physiologically relevant to the drug's mode of action. To gain further insight into the molecular genetic basis of INH resistance, 20 genes implicated in INH resistance were sequenced for INH resistance-associated mutations. Thirty-eight INH-monoresistant clinical isolates and 86 INH-susceptible isolates of M. tuberculosis were obtained from the Texas Department of Health and the Houston Tuberculosis Initiative. Epidemiologic independence was established for all isolates by IS6110 restriction fragment length polymorphism analysis. Susceptible isolates were matched with resistant isolates by molecular genetic group and IS6110 profiles. Spoligotyping was done with isolates with five or fewer IS6110 copies. A major genetic group was established on the basis of the polymorphisms in katG codon 463 and gyrA codon 95. MICs were determined by the E-test. Semiquantitative catalase assays were performed with isolates with mutations in the katG gene. When the 20 genes were sequenced, it was found that 17 (44.7%) INH-resistant isolates had a single-locus, resistance-associated mutation in the katG, mabA, or Rv1772 gene. Seventeen (44.7%) INH-resistant isolates had resistance-associated mutations in two or more genes, and 76% of all INH-resistant isolates had a mutation in the katG gene. Mutations were also identified in the fadE24, Rv1592c, Rv1772, Rv0340, and iniBAC genes, recently shown by DNA-based microarray experiments to be upregulated in response to INH. In general, the MICs were higher for isolates with mutations in katG and the isolates had reduced catalase activities. The results show that a variety of single nucleotide polymorphisms in multiple genes are found exclusively in INH-resistant clinical isolates. These genes either are involved in mycolic acid biosynthesis or are overexpressed as a response to the buildup or cellular toxicity of INH.

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