Incorporation of 18O into long-chain, secondary alcohols derived from ester mycolic acids in Mycobacterium phlei

Toriyama, Seiko; Imaizumi, Sadao; Tomiyasu, Ikuko; Masui, Masamiki; Yano, Ikuya

doi:10.1016/0005-2760(82)90363-0

Cited by 28 publications

(18 citation statements)

References 8 publications

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“…The b-keto esters, and possibly mycolones would be then oxidized, through the addition of an oxygen atom near the keto group by a putative Baeyer-Villiger monoxygenase, to yield a wax. The cleavage of the ester linkage would give primary alcohols (with an odd number of carbon atoms) whose oxidation would be at the origin of the C [44][45][46][47][48][49][50][51][52][53][54][55][56] and their probably b-oxidation C 35-44 series of mycobacteric acids. These latter substances were isolated both as free fatty acids and triacyl glycerol containing one mycobacteroyl residue (R 1 -CO) and two moles of conventional (C [16][17][18] ) fatty acyl substituents (R 3 -CO).…”

Section: Resultsmentioning

confidence: 99%

“…In this connection, a role for this type of long-chain fatty acids as mycolic acid precursors in growing cells has been suggested (41,42). What seems to support this hypothesis is the fact that a cell-free system from M. tuberculosis was shown in earlier studies to synthesize saturated and unsaturated C [30][31][32][33][34][35][36][37][38][39][40] and C [48][49][50][51][52][53][54][55][56] fatty acids, the latter exhibiting chain lengths similar to those of the meromycolic chain (14). Similarly, of the two condensing enzymes KasA and KasB, which are components of the fatty acid synthase II system implicated in the biosynthesis of the main (mero) chains of mycolic acids, characterized in M. tuberculosis, KasA specifically elongates palmitate into long-chain fatty acids averaging 40 carbons in length; KasB, in the presence of KasA, produces longer fatty acids averaging C 54 and structurally related to the meromycolic acids (43).…”

Section: Discussionmentioning

confidence: 99%

“…Flavin monooxygenases and BVMO have almost identical sequences (46), and several monooxygenases have been characterized in Corynebacterinae. For example, a putative BVMO has been detected in M. avium (47), a species containing keto-and its Baeyer-Villiger oxidation product, wax-mycolic acids (48)(49)(50). Interestingly, M. tuberculosis contains seven genes with BMVO motif (51).…”

Section: Discussionmentioning

confidence: 99%

“…This observation was also valid for long-chain primary alcohols. Furthermore, the meromycolic acids resulting from the reduction of the meroaldehydes exhibited carbon numbers between 50 and 55, whereas mycobacteric acids and long-chain primary alcohols contained a larger pool of homologs with shorter chain lengths, from C 35-44 and C [44][45][46][47][48][49][50][51][52][53][54][55][56] , respectively. Altogether, these data supported the hypothesis that mycobacteric acids (b) and the primary alcohols (f) derive from the mero aldehyde chain, whereas mycolones (a) and their reduced form (d) probably result from the decarboxylation of a b-keto ester.…”

Section: Identification Of the Natural Forms Of Mycobacteric Acids Ofmentioning

confidence: 99%

“…Long-chain C [40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56] fatty acids that exhibit the structural features of the main chains of mycolic acids have been (28) 5 19, 21). cis (E) and trans (Z ) are relative to the configuration of the double bonds.…”

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confidence: 99%

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Trafficking pathways of mycolic acids: structures, origin, mechanism of formation, and storage form of mycobacteric acids

Rafidinarivo

Lanéelle

Montrozier

et al. 2009

Journal of Lipid Research

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Mycolic acids, the hallmark of mycobacteria and related bacteria, are major and specific components of their cell envelope and essential for the mycobacterial survival. Mycobacteria contain structurally related long-chain lipids, but the metabolic relationships between these various classes of compounds remain obscure. To address this question a series of C 35 to C 54 nonhydroxylated fatty acids (mycobacteric acids), ketones, and alcohols structurally related to the C 70-80 dicyclopropanated or diethylenic mycolic acids were characterized in three mycobacterial strains and their structures compared. The relationships between these longchain acids and mycolic acids were established by following the in vivo traffic of 14 C labeled a-mycolic acids purified from the same mycobacterial species. The labeling was exclusively found in mycobacteric acids. The mechanism of this degradation was established by incorporation of 18 O 2 into long-chain lipids and shown to consist in the rupture of mycolic acids between carbon 3 and 4 by a BaeyerVilliger-like reaction. We also demonstrated that mycobacteric acids occur exclusively in the triacylglycerol (TAG) fraction where one molecule of these acids esterifies one of the three hydroxyl groups of glycerol. Altogether, these data suggest that these compounds represent a pathway of metabolic energy that would be used by mycobacteria in particular circumstances. Mycolic acids, 2-alkyl-branched, 3-hydroxylated longchain fatty acids, represent major (up to 40% of cell wall dry mass) and specific constituents of the envelope of members of the genus Mycobacterium (M.) that includes several pathogens such as M. tuberculosis and M. leprae, the causative agents of tuberculosis and leprosy, respectively. These fatty acids play a crucial structural role in the envelope architecture (1-4) and are essential for the mycobacterial growth (5-7). Mycolic acids covalently linked to the cell wall arabinogalactan are organized with other lipids to form an outer barrier with an extremely low fluidity that confers an exceptional low permeability to mycobacteria (8). Trehalose mycolates, found noncovalently attached to the cell wall core, are known to be important for the physiology and virulence of M. tuberculosis (3). In addition, the biosynthesis of mycolic acids is the target of several antituberculous drugs, notably isoniazid (2,3,9).Mycolic acids are found in mycobacterial species as a mixture of structurally related molecules that differ from one another by the nature of the chemical groups at the socalled "proximal" and "distal" positions (relative to the carboxyl group) of their main "meromycolic" chain (Fig. 1). The least polar a-mycolates is ubiquitous in mycobacteria and consist of C 74-82 fatty acids that contain two cis cyclopropyl groups or cis/trans double bonds at the proximal and distal positions (Fig. 1); shorter apolar structural analogs (C 60-68 ), called a′-mycolates, may occur in someThe NMR equipment was funded via European structural funds, CNRS, and the Région Midi-...

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