Relationship Between the Uptake of Isoniazid and Its Action on In Vivo Mycolic Acid Synthesis in Mycobacterium tuberculosis

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.

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Effects of isoniazid on mycolic acid synthesis in Mycobacterium tuberculosis and on its cell envelope

Biochemical Journal ◽

10.1042/bj1170027pa ◽

1970 ◽

Vol 117 (2) ◽

pp. 27P-27P ◽

Cited By ~ 7

Author(s):

F G A Winder ◽

P Collins ◽

S A Rooney

Keyword(s):

Mycobacterium Tuberculosis ◽

Cell Envelope ◽

Acid Synthesis ◽

Mycolic Acid

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The aceE involves in mycolic acid synthesis and biofilm formation in Mycobacterium smegmatis

10.21203/rs.3.rs-23060/v1 ◽

2020 ◽

Author(s):

Suting Chen ◽

Tianlu Teng ◽

Shuan Wen ◽

Tingting Zhang ◽

Hairong Huang

Keyword(s):

Cell Wall ◽

Biofilm Formation ◽

Morphological Changes ◽

Acid Synthesis ◽

Mycolic Acid ◽

Colony Morphology ◽

Wall Structure ◽

Wild Type ◽

Mycobacterial Cell Wall

Abstract Background: The integrity of cell wall structure is highly significant for the in vivo survival for mycobacteria. However, the mechanisms underlying the biosynthesis of mycobacterial cell wall remain poorly understood. aceE encodes the E1 component of pyruvate dehydrogenase (PDH)complex. This study aimed to know the functional role of aceE gene in cell wall biosynthesis in M. smegmatis.Results: We observed that the colony morphology of aceE-deficient mutants(aceE-mut)was quite different from the wild-type(WT) strain during the transposon library screening of M.smegmatis, smaller and smoother on the solid culture medium. Notably, the aceE-mut lost its ability of growing aggregately and biofilm forming, which are two very important features of mycobacteria.The morphological changes of the aceE-mut strain were further confirmed by electron microscopy that presented shorter, smoother and thinner images in contrast withWT strain.Additionally, the analysis of mycolic acid(MA)using LC-MS indicated deficiency of alpha-MA and epoxy-MA in aceE-mut strain whereas complementation of the aceE-mut with a wild-type aceEgene restored the composition of MA. Conclusions: Overall, this study indicates that aceE gene plays a significant role in the mycolic acid synthesis and affects the colony morphology and biofilm formation of M.smegmatis.

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Effects of Ethionamide and Isoxyl on Mycolic Acid Synthesis in Mycobacterium tuberculosis bcg

Journal of General Microbiology ◽

10.1099/00221287-66-3-379 ◽

1971 ◽

Vol 66 (3) ◽

pp. 379-380 ◽

Cited By ~ 47

Author(s):

F. G. Winder ◽

P. B. Collins ◽

D. Whelan

Keyword(s):

Mycobacterium Tuberculosis ◽

Acid Synthesis ◽

Mycolic Acid

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Isoxyl Activation Is Required for Bacteriostatic Activity against Mycobacterium tuberculosis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.00433-07 ◽

2007 ◽

Vol 51 (11) ◽

pp. 3824-3829 ◽

Cited By ~ 22

Author(s):

Jana Korduláková ◽

Yves L. Janin ◽

Avraham Liav ◽

Nathalie Barilone ◽

Tiago Dos Vultos ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Acid Synthesis ◽

Mycolic Acid ◽

Chemical Transformations ◽

Mycolic Acids ◽

Monooxygenase Gene ◽

Acid Pathway ◽

The 1960S ◽

First Time

ABSTRACT Isoxyl (ISO), a thiourea derivative that was successfully used for the clinical treatment of tuberculosis during the 1960s, is an inhibitor of the synthesis of oleic and mycolic acids in Mycobacterium tuberculosis. Its effect on oleic acid synthesis has been shown to be attributable to its inhibitory activity on the stearoyl-coenzyme A desaturase DesA3, but its enzymatic target(s) in the mycolic acid pathway remains to be identified. With the goal of elucidating the mode of action of ISO, we have isolated a number of spontaneous ISO-resistant mutants of M. tuberculosis and undertaken their genotypic characterization. We report here the characterization of a subset of these strains carrying mutations in the monooxygenase gene ethA. Through complementation studies, we demonstrate for the first time that the EthA-mediated oxidation of ISO is absolutely required for this prodrug to inhibit its lethal enzymatic target(s) in M. tuberculosis. An analysis of the metabolites resulting from the in vitro transformation of ISO by purified EthA revealed the occurrence of a formimidamide allowing the formulation of an activation pathway in which the oxidation of ISO catalyzed by EthA is followed by chemical transformations involving extrusion or elimination and, finally, hydrolysis.

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Mycobacterium tuberculosis Proteins Involved in Mycolic Acid Synthesis and Transport Localize Dynamically to the Old Growing Pole and Septum

PLoS ONE ◽

10.1371/journal.pone.0097148 ◽

2014 ◽

Vol 9 (5) ◽

pp. e97148 ◽

Cited By ~ 51

Author(s):

Clément Carel ◽

Kanjana Nukdee ◽

Sylvain Cantaloube ◽

Mélanie Bonne ◽

Cheikh T. Diagne ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Acid Synthesis ◽

Mycolic Acid

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Antigen 85C Inhibition Restricts Mycobacterium tuberculosis Growth through Disruption of Cord Factor Biosynthesis

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.05742-11 ◽

2012 ◽

Vol 56 (4) ◽

pp. 1735-1743 ◽

Cited By ~ 44

Author(s):

Thulasi Warrier ◽

Marielle Tropis ◽

Jim Werngren ◽

Anne Diehl ◽

Martin Gengenbacher ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Cell Envelope ◽

Acid Synthesis ◽

Multidrug Resistant ◽

Mycolic Acid ◽

Broth Culture ◽

Nuclear Magnetic Resonance Analysis ◽

Transferase Activity ◽

Content Type ◽

Substrate Analogs

ABSTRACTThe antigen 85 (Ag85) protein family, consisting of Ag85A, -B, and -C, is vital forMycobacterium tuberculosisdue to its role in cell envelope biogenesis. The mycoloyl transferase activity of these proteins generates trehalose dimycolate (TDM), an envelope lipid essential forM. tuberculosisvirulence, and cell wall arabinogalactan-linked mycolic acids. Inhibition of these enzymes through substrate analogs hinders growth of mycobacteria, but a link to mycolic acid synthesis has not been established. In this study, we characterized a novel inhibitor of Ag85C, 2-amino-6-propyl-4,5,6,7-tetrahydro-1-benzothiophene-3-carbonitrile (I3-AG85). I3-AG85 was isolated from a panel of four inhibitors that exhibited structure- and dose-dependent inhibition ofM. tuberculosisdivision in broth culture. I3-AG85 also inhibitedM. tuberculosissurvival in infected primary macrophages. Importantly, it displayed an identical MIC against the drug-susceptible H37Rv reference strain and a panel of extensively drug-resistant/multidrug-resistantM. tuberculosisstrains. Nuclear magnetic resonance analysis indicated binding of I3-AG85 to Ag85C, similar to its binding to the artificial substrate octylthioglucoside. Quantification of mycolic acid-linked lipids of theM. tuberculosisenvelope showed a specific blockade of TDM synthesis. This was accompanied by accumulation of trehalose monomycolate, while the overall mycolic acid abundance remained unchanged. Inhibition of Ag85C activity also disrupted the integrity of theM. tuberculosisenvelope. I3-AG85 inhibited the division of and reduced TDM synthesis in anM. tuberculosisstrain deficient in Ag85C. Our results indicate that Ag85 proteins are promising targets for novel antimycobacterial drug design.

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Mycolic acid biosynthesis and enzymic characterization of the β-ketoacyl-ACP synthase A-condensing enzyme from Mycobacterium tuberculosis

Biochemical Journal ◽

10.1042/bj20011628 ◽

2002 ◽

Vol 364 (2) ◽

pp. 423-430 ◽

Cited By ~ 88

Author(s):

Laurent KREMER ◽

Lynn G. DOVER ◽

Séverine CARRÈRE ◽

K. Madhavan NAMPOOTHIRI ◽

Sarah LESJEAN ◽

...

Keyword(s):

Mycobacterium Tuberculosis ◽

Fatty Acid Synthase ◽

Acyl Carrier Protein ◽

Mycolic Acid ◽

Mycobacterium Chelonae ◽

Mycolic Acids ◽

Condensation Activity ◽

Fas Ii

Mycolic acids consist of long-chain α-alkyl-β-hydroxy fatty acids that are produced by successive rounds of elongation catalysed by a type II fatty acid synthase (FAS-II). A key feature in the elongation process is the condensation of a two-carbon unit from malonyl-acyl-carrier protein (ACP) to a growing acyl-ACP chain catalysed by a β-ketoacyl-ACP synthase (Kas). In the present study, we provide evidence that kasA from Mycobacterium tuberculosis encodes an enzyme that elongates in vivo the meromycolate chain, in both Mycobacterium smegmatis and Mycobacterium chelonae. We demonstrate that KasA belongs to the FAS-II system, which utilizes primarily palmitoyl-ACP rather than short-chain acyl-ACP primers. Furthermore, in an in vitro condensing assay using purified recombinant KasA, palmitoyl-AcpM and malonyl-AcpM, KasA was found to express Kas activity. Also, mutated KasA proteins, with mutation of Cys171, His311, Lys340 and His345 to Ala abrogated the condensation activity of KasA in vitro completely. Finally, purified KasA was highly sensitive to cerulenin, a well-known inhibitor of Kas, which may lead to the development of novel anti-mycobacterial drugs targeting KasA.

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