Biosynthesis of Corynomycolic Acid from Two Molecules of Palmitic Acid

Gastambide-Odier, M; Lederer, E.

doi:10.1038/1841563b0

Cited by 47 publications

(16 citation statements)

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“…Indeed, the intervention of two molecules of palmitic acid in this synthesis has been first proved by incubating C. diphtheriae cells with [1-14 C]palmitic acid. In the resulting corynomycolic acid, the labeling was specifically found in carbon atoms 1 and 3 (17). Moreover, a particulate cell-free preparation of C. diphtheriae incubated with [1-14 C]palmitate was shown to produce a ␤-keto ester specifically labeled on carbon atoms 1 and 3 (49).…”

Section: Discussionmentioning

confidence: 98%

“…As far as the mechanism of the condensation reaction that yield mycolic acids is concerned, it has been postulated from structural considerations that the C 32 corynomycolic acid could result from a condensation of two molecules of C 16 (17). Indeed, the intervention of two molecules of palmitic acid in this synthesis has been first proved by incubating C. diphtheriae cells with [1-14 C]palmitic acid.…”

Section: Discussionmentioning

confidence: 99%

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The Acyl-AMP Ligase FadD32 and AccD4-containing Acyl-CoA Carboxylase Are Required for the Synthesis of Mycolic Acids and Essential for Mycobacterial Growth

Portevin

Silva

Montrozier

et al. 2005

Journal of Biological Chemistry

173

195

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Mycolic acids are major and specific long-chain fatty acids of the cell envelope of several important human pathogens such as Mycobacterium tuberculosis, M. leprae, and Corynebacterium diphtheriae. Their biosynthesis is essential for mycobacterial growth and represents an attractive target for developing new antituberculous drugs. We have previously shown that the pks13 gene encodes condensase, the enzyme that performs the final condensation step of mycolic acid biosynthesis and is flanked by two genes, fadD32 and accD4. To determine the functions of the gene products we generated two mutants of C. glutamicum with an insertion/deletion within either fadD32 or accD4. The two mutant strains were deficient in mycolic acid production and exhibited the colony morphology that typifies the mycolate-less mutants of corynebacteria. Application of multiple analytical approaches to the analysis of the mutants demonstrated the accumulation of a tetradecylmalonic acid in the ⌬fadD32::km mutant and its absence from the ⌬accD4::km strain. The parental corynebacterial phenotype was restored upon the transfer of the wild-type fadD32 and accD4 genes in the mutants. These data demonstrated that both FadD32 and AccD4-containing acyl-CoA carboxylase are required for the production of mycolic acids. They also prove that the proteins catalyze, respectively, the activation of one fatty acid substrate and the carboxylation of the other substrate, solving the long-debated question of the mechanism involved in the condensation reaction. We used comparative genomics and applied a combination of molecular biology and proteomic technologies to the analysis of proteins that co-immunoprecipitated with AccD4. This resulted in the identification of AccA3 and AccD5 as subunits of the acyl-CoA carboxylase. Finally, we used conditionally replicative plasmids to show that both the fadD32 and accD4 genes are essential for the survival of M. smegmatis. Thus, in addition to Pks13, FadD32 and AccD4 are promising targets for the development of new antimicrobial drugs against pathogenic species of mycobacteria and related microorganisms.

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Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

The Acyl-AMP Ligase FadD32 and AccD4-containing Acyl-CoA Carboxylase Are Required for the Synthesis of Mycolic Acids and Essential for Mycobacterial Growth

Portevin

Silva

Montrozier

et al. 2005

Journal of Biological Chemistry

173

195

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“…Also high proportions of branched-chain fatty acids which are characteristic of some gram-positive bacterial families are missing in strain l l / x , although small amounts of such fatty acids cannot be excluded. If the lipid composition of strain l l / x is compared with the general lipid patterns of Mycobaeteria, some similarities are noticed : large proportions of triglycerides and of phosphoinositides and absence of cyclopropane fatty acids (apart from those of very high molecular weight [59] present in Mycobacteria). Moreover, the accumulation of two different storage materials is believed to be characteristic of Mycobacteria [34].…”

Section: Discussionmentioning

confidence: 98%

The “Free” Lipids of Two Different Strains of Hydrogen‐Oxidizing Bacteria in Relation to Their Growth Phases

Thiele

Dreysel

Hermann³

1972

European Journal of Biochemistry

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Two strains of hydrogen‐oxidizing bacteria were used: Hydrogenomonas eutropha strain H16 and strain 11/x. The former is a gram‐negative flagellated rod and has been relatively well known with respect to its morphological, physiological, and biochemical properties. The latter is a gram‐positive, non spore‐forming, motile small rod the definite classification of which is unknown as yet. Both strains were grown chemolithotrophically in submerged culture with a limited nitrogen‐source and supplied with a gas mixture of H2, O2, and CO2. The lipid composition of the bacteria was determined at the end of the exponential phase (I), at the storage phase (II), and after reutilization of storage material (III). Along with the accumulation of poly(3‐hydroxybutyric acid) as the major storage material in strain H16 the amount of other lipids was shown to increase 1.8‐fold at phase II and to decrease at phase III. There is little or no change in the lipid pattern in various growth phases. It is suggested that the 1.8‐fold increase of the latter lipids during phase II is due to the synthesis of membrane lipids that are required for the formation of membranes surrounding the intra‐cellular granules of accumulating poly(3‐hydroxybutyric acid). In strain 11/x the amount of lipids increases 7 times along with an equal increase of carbohydrates at phase II. The majority of accumulated lipids consists of triglycerides free of significant amounts of unusual acyl group. It is suggested that there is a true storage of triglycerides that are reutilized during phase III. The lipid pattern of strain H16 is characterized by a high proportion of “strongly bound lipids” that consist predominantly of phospholipids. Characteristic lipid components are phosphatidylethanolamine, phosphatidylglycerol, and diphosphatidylglycerol, while coenzyme Q8 (0.41 μmol/g bacterial dry weight) has been found among the neutral lipids. A C17 cyclopropane acid (probably cis‐9,10‐methylene hexadecanoic acid) is present in all saponifiable lipids. The lipid pattern of strain 11/x is characterized by a high proportion of “loosely bound lipids” that consist predominantly of neutral lipids, particularly of triglycerides. Among the polar lipids, diphosphatidylglycerol and phosphoinositides are most abundant, and several unknown phospholipids are also present. No cyclopropane fatty acid has been found. The possible use of strain 11/x as a source of nutritional fat is discussed.

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“…The four oxygenated mycolic acids are synthesized by the same mechanism as the ␣-mycolic acid. Walker et al (112) first described the mechanism for the Claisen-type condensation in the synthesis of corynomycolic acid in Corynebacterium diphtheriae, based on a study by Gastambide-Odier and Lederer (37). Later, Takayama and Qureshi (100) used it to describe this reaction in M. tuberculosis.…”

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confidence: 99%

Pathway to Synthesis and Processing of Mycolic Acids in Mycobacterium tuberculosis

2005

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Mycobacterium tuberculosis is known to synthesize α-, methoxy-, and keto-mycolic acids. We propose a detailed pathway to the biosynthesis of all mycolic acids in M. tuberculosis. Fatty acid synthetase I provides C20-S-coenzyme A to the fatty acid synthetase II system (FAS-IIA). Modules of FAS-IIA and FAS-IIB introduce cis unsaturation at two locations on a growing meroacid chain to yield three different forms of cis,cis-diunsaturated fatty acids (intermediates to α-, methoxy-, and keto-meroacids). These are methylated, and the mature meroacids and carboxylated C26-S-acyl carrier protein enter into the final Claisen-type condensation with polyketide synthase-13 (Pks13) to yield mycolyl-S-Pks13. We list candidate genes in the genome encoding the proposed dehydrase and isomerase in the FAS-IIA and FAS-IIB modules. We propose that the processing of mycolic acids begins by transfer of mycolic acids from mycolyl-S-Pks13 to d-mannopyranosyl-1-phosphoheptaprenol to yield 6-O-mycolyl-β-d-mannopyranosyl-1-phosphoheptaprenol and then to trehalose 6-phosphate to yield phosphorylated trehalose monomycolate (TMM-P). Phosphatase releases the phosphate group to yield TMM, which is immediately transported outside the cell by the ABC transporter. Antigen 85 then catalyzes the transfer of a mycolyl group from TMM to the cell wall arabinogalactan and to other TMMs to produce arabinogalactan-mycolate and trehalose dimycolate, respectively. We list candidate genes in the genome that encode the proposed mycolyltransferases I and II, phosphatase, and ABC transporter. The enzymes within this total pathway are targets for new drug discovery

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Biosynthesis of Corynomycolic Acid from Two Molecules of Palmitic Acid

Cited by 47 publications

References 0 publications

The Acyl-AMP Ligase FadD32 and AccD4-containing Acyl-CoA Carboxylase Are Required for the Synthesis of Mycolic Acids and Essential for Mycobacterial Growth

The Acyl-AMP Ligase FadD32 and AccD4-containing Acyl-CoA Carboxylase Are Required for the Synthesis of Mycolic Acids and Essential for Mycobacterial Growth

The “Free” Lipids of Two Different Strains of Hydrogen‐Oxidizing Bacteria in Relation to Their Growth Phases

Pathway to Synthesis and Processing of Mycolic Acids in Mycobacterium tuberculosis

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