Tracking the Putative Biosynthetic Precursors of Oxygenated Mycolates of Mycobacterium tuberculosis

Abstract

Disruption of the mma4 gene (renamed hma) of Mycobacterium tuberculosis has yielded a mutant strain defective in the synthesis of both keto- and methoxymycolates, with an altered cell-wall permeability to small molecules and a decreased virulence in the mouse model of infection (Dubnau, E., Chan, J., Raynaud, C., Mohan, V. P., Lanéelle, M. A., Yu, K., Quémard, A., Smith, I., and Daffé, M. (2000) Mol. Microbiol. 36, 630–637). Assuming that the mutant would accumulate the putative precursors of the oxygenated mycolates of M. tuberculosis, a detailed structural analysis of mycolates from the hma-inactivated strain was performed using a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, proton NMR spectroscopy, and chemical degradation techniques. These consisted most exclusively of α-mycolates, composed of equal amounts of C76-C82 dicyclopropanated (α1) and of C77-C79 monoethylenic monocyclopropanated (α2) mycolates, the double bond being located at the “distal” position. In addition, small amounts ofcis-epoxymycolates, structurally related to α2-mycolates, was produced by the mutant strain. Complementation of the hma-inactivated mutant with the wild-type gene resulted in the disappearance of the newly identified mycolates and the production of keto- and methoxymycolates of M. tuberculosis. Introduction of the hma gene inMycobacterium smegmatis led to the lowering of diethylenic α mycolates of the recipient strain and the production of keto- and hydroxymycolates. These data indicate that long-chain ethylenic compounds may be the precursors of the oxygenated mycolates of M. tuberculosis. Because the lack of production of several methyltransferases involved in the biosynthesis of mycolates is known to decrease the virulence of the tubercle bacillus, the identification of the substrates of these enzymes should help in the design of inhibitors of the growth of M. tuberculosis. Disruption of the mma4 gene (renamed hma) of Mycobacterium tuberculosis has yielded a mutant strain defective in the synthesis of both keto- and methoxymycolates, with an altered cell-wall permeability to small molecules and a decreased virulence in the mouse model of infection (Dubnau, E., Chan, J., Raynaud, C., Mohan, V. P., Lanéelle, M. A., Yu, K., Quémard, A., Smith, I., and Daffé, M. (2000) Mol. Microbiol. 36, 630–637). Assuming that the mutant would accumulate the putative precursors of the oxygenated mycolates of M. tuberculosis, a detailed structural analysis of mycolates from the hma-inactivated strain was performed using a combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, proton NMR spectroscopy, and chemical degradation techniques. These consisted most exclusively of α-mycolates, composed of equal amounts of C76-C82 dicyclopropanated (α1) and of C77-C79 monoethylenic monocyclopropanated (α2) mycolates, the double bond being located at the “distal” position. In addition, small amounts ofcis-epoxymycolates, structurally related to α2-mycolates, was produced by the mutant strain. Complementation of the hma-inactivated mutant with the wild-type gene resulted in the disappearance of the newly identified mycolates and the production of keto- and methoxymycolates of M. tuberculosis. Introduction of the hma gene inMycobacterium smegmatis led to the lowering of diethylenic α mycolates of the recipient strain and the production of keto- and hydroxymycolates. These data indicate that long-chain ethylenic compounds may be the precursors of the oxygenated mycolates of M. tuberculosis. Because the lack of production of several methyltransferases involved in the biosynthesis of mycolates is known to decrease the virulence of the tubercle bacillus, the identification of the substrates of these enzymes should help in the design of inhibitors of the growth of M. tuberculosis. fatty-acid synthase bacillus Calmette-Guérin gas chromatography mass spectrometry matrix-assisted laser desorption/ionization time-of-flight electron impact Mycolic acids, α-branched β-hydroxylated long-chain fatty acids (up to 90 carbon atoms), are the hallmark of theMycobacterium genus that comprises several human pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, the causative agents of tuberculosis and leprosy, respectively. These molecules represent major cell envelope components (40–60% of the cell dry weight) and are found covalently linked to the cell wall arabinogalactan or esterifying trehalose and glycerol; both types of mycolic acid-containing components are believed to play a crucial role in the structure and function of the mycobacterial cell envelope (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, 2Goren M.B. Brennan P.J. Youmans G.P. Tuberculosis. Saunders Co., Philadelphia1979: 63-193Google Scholar, 3Daffé M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). Mycolic acids attached to the cell wall arabinogalactan are organized with other lipids to form an outer permeability barrier with an extremely low fluidity that confers an exceptional low permeability to mycobacteria and may explain their intrinsic resistance to many antibiotics (4Brennan P.J. Nikaido H. Annu. Rev. PubMed Scopus Google Scholar). mycolates in related both to the and virulence of Mycobacterium M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google and are to the and biosynthesis of these acids, these are to the Mycobacterium and their is the identified by the major J. Microbiol. PubMed Scopus Google Scholar, K. PubMed Scopus Google Scholar, K. PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar). the of tuberculosis by and the the of the biosynthesis to mycolates a major of the of M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar, C. J. of the and Scholar, Google the help of K. 1998; PubMed Scopus Google Scholar, of the biosynthesis to mycolic acids is is that the known mycobacterial fatty-acid in the of types of mycolates or their a synthase that has to be a is to and fatty acids, may be in mycolates as the or as substrates of the that and an that to A. E. Quémard A. V. PubMed Scopus Google Scholar, H. Lanéelle Quémard A. 2000; PubMed Scopus Google is with the to the types of acids in mycobacterial as a of related molecules that from by the of chemical located of their In of the M. tuberculosis types of mycolates are M. Lanéelle C. V. Microbiol. Scopus Google Scholar, M. M. Microbiol. PubMed Scopus Google Scholar). mycolates, α-mycolates, are composed of C76-C82 fatty acids Lanéelle M.A. C. Daffé M. PubMed Scopus Google and at the and “distal” to the of the and mycolates of Lanéelle M.A. C. Daffé M. PubMed Scopus Google and or a an at the and a or a keto- an at the These structural in mycolates may be of crucial has that in the of these chemical the permeability of the cell envelope to and the virulence of the mutant in (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, Mol. Microbiol. 1998; PubMed Scopus Google Scholar, Mol. 2000; PubMed Scopus Google Scholar). the that the chemical in the mycolic E. Rev. Scopus Google a that may explain the of methyltransferases ethylenic precursors to and in mycolates has K. 1998; PubMed Scopus Google Scholar). to explain the synthesis of keto- and the of the double bond of a a with an using by the gene mma4 A. PubMed Scopus Google Scholar). gene with the function in Mycobacterium E. Lanéelle M.A. A. Daffé M. Quémard A. Mol. Microbiol. PubMed Scopus Google in Mycobacterium smegmatis has to to the the to In addition, the produced amounts of acids with an structurally related to the acids of M. amounts of these acids in mycobacterial keto- methoxymycolates, the that acids be the precursors of both keto- and acids A. Lanéelle M.A. H. E. Daffé M. J. PubMed Scopus Google Scholar). a mutant strain of M. tuberculosis in gene hma has and to be of both keto- and acids (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). the the oxygenated mycolates tuberculosis, the chemical of molecules by to these oxygenated mycolates analysis of the mass of the fatty acids from the mutant strain the of structurally related to and from the strain Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). In an to these putative precursors of oxygenated mycolic acids of M. tuberculosis, a detailed analysis of the mycolic of the hma mutant was performed using the combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, proton spectroscopy, and chemical degradation that the of the from M. M. smegmatis the production by the recipient strain of amounts of acids and small amounts of acids E. Lanéelle M.A. A. Daffé M. Quémard A. Mol. Microbiol. PubMed Scopus Google Scholar). of the gene tuberculosis hma has resulted in the of the production of the oxygenated mycolates in M. the and acids (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). was that the hma gene is involved in the synthesis of oxygenated mycolic acids and that acids are to be precursors of and tuberculosis. mutant strain was found to types of mycolic acids from the that these molecules may represent the precursors of the oxygenated mycolates tuberculosis Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). the was to the chemical of these of mass spectrometry, NMR spectroscopy, and chemical degradation to the analysis of the of mycolates produced by the mutant several in the of the the mutant strain as mycolates as the that the in these molecules is the of the both the mutant and amounts of dicyclopropanated that the the production of of the mutant produced amounts of a of mycolates, a of monoethylenic monocyclopropanated α-mycolates, and a of monocyclopropanated the ethylenic the growth of the that from of the mutant strain with the wild-type resulted in the disappearance of the types of mycolates and the production by the strain of the types of mycolates of the strain. of the hma gene in M. smegmatis led to the lowering of diethylenic of the recipient strain and the production of keto- and hydroxymycolates. that the in the structure of mycolates of the mutant are to the of the hma gene and the biosynthesis of mycolic of the related to the biosynthesis of mycolic acids is the that to the of the oxygenated at the of the of substrates to oxygenated chemical a E. Rev. Scopus Google Scholar, C. J. Lanéelle Lanéelle M.A. PubMed Scopus Google a to an as known or an ethylenic in a should in the as function A. PubMed Scopus Google Scholar). Because in the hma-inactivated is to that the ethylenic double bond in the of the mutant strain is the of In the the the of the ethylenic bond be a or a In both an would be to the keto- or the the of in the are to found in oxygenated mycolates of the strain and in the of the strain the in and oxygenated mycolates Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar, M. H. H. M. PubMed Scopus Google and to be to the of the methyltransferases with to the of the PubMed Scopus Google the synthesis of oxygenated mycolic acids by the from E. Rev. Scopus Google Scholar). the the the of production of and related oxygenated compounds in Mycobacterium Draper P. J. Microbiol. Google and other mycobacterial C. Lanéelle M.A. Daffé M. H. Lanéelle J. PubMed Scopus Google the and the of these of the other has that these molecules are by the would be a diethylenic that would be by or the to acids a 3Daffé M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). that the mutant produced dicyclopropanated acids as the strain and in data are with the of to the synthesis of acids and involved in the synthesis of oxygenated mycolic the would be altered by the of may a of enzymes are the synthesis of the may from by the of enzymes involved in the of chemical in the of amounts of ethylenic in the hma-inactivated to of oxygenated mycolates of the the that ethylenic fatty may be the biosynthesis of oxygenated mycolates in the and the strain. In the of the hma these putative precursors would be by the to the synthesis of oxygenated mycolates and is the the of the precursors and of the the mutant produced monoethylenic monocyclopropanated (α2) and monocyclopropanated mycolates, the and and carbon the Lanéelle M.A. C. Daffé M. PubMed Scopus Google M. M. PubMed Scopus Google Scholar). of the detailed of mycolic acids, to the that the in oxygenated mycolates are located the and the oxygenated in the other of the that the of an oxygenated function at in the carbon to the of the in of the synthesis of the a the oxygenated should be of the methyltransferases identified in the of M. tuberculosis J. C. K. K. K. K. A. J. K. J. M.A. J. K. J. K. 1998; PubMed Scopus Google Scholar). These enzymes are to be the of in the mycolic that may the and virulence of the tubercle the of a by a double bond in esterifying trehalose the of tubercle and the virulence of the mutant strain Mol. 2000; PubMed Scopus Google Scholar). the lack of production of keto- and methoxymycolates in M. tuberculosis in both a of the permeability and an of virulence of the mutant strain (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). These in to the that the biosynthesis to mycolic acids is the of the most that may represent the of In the identification of putative precursors of oxygenated mycolates should help in the design of that would be as inhibitors of the of the methyltransferases are the their are Smith J. PubMed Scopus Google the inhibitors of may the of other in an that may be or the Mycolic acids, α-branched β-hydroxylated long-chain fatty acids (up to 90 carbon atoms), are the hallmark of theMycobacterium genus that comprises several human pathogens such as Mycobacterium tuberculosis and Mycobacterium leprae, the causative agents of tuberculosis and leprosy, respectively. These molecules represent major cell envelope components (40–60% of the cell dry weight) and are found covalently linked to the cell wall arabinogalactan or esterifying trehalose and glycerol; both types of mycolic acid-containing components are believed to play a crucial role in the structure and function of the mycobacterial cell envelope (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, 2Goren M.B. Brennan P.J. Youmans G.P. Tuberculosis. Saunders Co., Philadelphia1979: 63-193Google Scholar, 3Daffé M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). Mycolic acids attached to the cell wall arabinogalactan are organized with other lipids to form an outer permeability barrier with an extremely low fluidity that confers an exceptional low permeability to mycobacteria and may explain their intrinsic resistance to many antibiotics (4Brennan P.J. Nikaido H. Annu. Rev. PubMed Scopus Google Scholar). mycolates in related both to the and virulence of Mycobacterium M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). and are to the and biosynthesis of these acids, these are to the Mycobacterium and their is the identified by the major J. Microbiol. PubMed Scopus Google Scholar, K. PubMed Scopus Google Scholar, K. PubMed Scopus Google Scholar, 1998; PubMed Scopus Google Scholar). the of tuberculosis by and the the of the biosynthesis to mycolates a major of the of M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar, C. J. of the and Scholar, Google the help of K. 1998; PubMed Scopus Google Scholar, of the biosynthesis to mycolic acids is is that the known mycobacterial fatty-acid in the of types of mycolates or their a synthase that has to be a is to and fatty acids, may be in mycolates as the or as substrates of the that and an that to A. E. Quémard A. V. PubMed Scopus Google Scholar, H. Lanéelle Quémard A. 2000; PubMed Scopus Google is with the to the types of Mycolic acids in mycobacterial as a of related molecules that from by the of chemical located of their In of the M. tuberculosis types of mycolates are M. Lanéelle C. V. Microbiol. Scopus Google Scholar, M. M. Microbiol. PubMed Scopus Google Scholar). mycolates, α-mycolates, are composed of C76-C82 fatty acids Lanéelle M.A. C. Daffé M. PubMed Scopus Google and at the and “distal” to the of the and mycolates of Lanéelle M.A. C. Daffé M. PubMed Scopus Google and or a an at the and a or a keto- an at the These structural in mycolates may be of crucial has that in the of these chemical the permeability of the cell envelope to and the virulence of the mutant in (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, Mol. Microbiol. 1998; PubMed Scopus Google Scholar, Mol. 2000; PubMed Scopus Google Scholar). the that the chemical in the mycolic E. Rev. Scopus Google a that may explain the of methyltransferases ethylenic precursors to and in mycolates has K. 1998; PubMed Scopus Google Scholar). to explain the synthesis of keto- and the of the double bond of a a with an using by the gene mma4 A. PubMed Scopus Google Scholar). gene with the function in Mycobacterium E. Lanéelle M.A. A. Daffé M. Quémard A. Mol. Microbiol. PubMed Scopus Google in Mycobacterium smegmatis has to to the the to In addition, the produced amounts of acids with an structurally related to the acids of M. amounts of these acids in mycobacterial keto- methoxymycolates, the that acids be the precursors of both keto- and acids A. Lanéelle M.A. H. E. Daffé M. J. PubMed Scopus Google Scholar). a mutant strain of M. tuberculosis in gene hma has and to be of both keto- and acids (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar, Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). the the oxygenated mycolates tuberculosis, the chemical of molecules by to these oxygenated mycolates analysis of the mass of the fatty acids from the mutant strain the of structurally related to and from the strain Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). In an to these putative precursors of oxygenated mycolic acids of M. tuberculosis, a detailed analysis of the mycolic of the hma mutant was performed using the combination of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, proton spectroscopy, and chemical degradation techniques. that the of the from M. M. smegmatis the production by the recipient strain of amounts of acids and small amounts of acids E. Lanéelle M.A. A. Daffé M. Quémard A. Mol. Microbiol. PubMed Scopus Google Scholar). of the gene tuberculosis hma has resulted in the of the production of the oxygenated mycolates in M. the and acids (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). was that the hma gene is involved in the synthesis of oxygenated mycolic acids and that acids are to be precursors of and tuberculosis. mutant strain was found to types of mycolic acids from the that these molecules may represent the precursors of the oxygenated mycolates tuberculosis Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). the was to the chemical of these of mass spectrometry, NMR spectroscopy, and chemical degradation to the analysis of the of mycolates produced by the mutant several in the of the the mutant strain as mycolates as the that the in these molecules is the of the both the mutant and amounts of dicyclopropanated that the the production of of the mutant produced amounts of a of mycolates, a of monoethylenic monocyclopropanated α-mycolates, and a of monocyclopropanated the ethylenic the growth of the that from of the mutant strain with the wild-type resulted in the disappearance of the types of mycolates and the production by the strain of the types of mycolates of the strain. of the hma gene in M. smegmatis led to the lowering of diethylenic of the recipient strain and the production of keto- and hydroxymycolates. that the in the structure of mycolates of the mutant are to the of the hma gene and the biosynthesis of mycolic of the related to the biosynthesis of mycolic acids is the that to the of the oxygenated at the of the of substrates to oxygenated chemical a E. Rev. Scopus Google Scholar, C. J. Lanéelle Lanéelle M.A. PubMed Scopus Google a to an as known or an ethylenic in a should in the as function A. PubMed Scopus Google Scholar). Because in the hma-inactivated is to that the ethylenic double bond in the of the mutant strain is the of In the the the of the ethylenic bond be a or a In both an would be to the keto- or the the of in the are to found in oxygenated mycolates of the strain and in the of the strain the in and oxygenated mycolates Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar, M. H. H. M. PubMed Scopus Google and to be to the of the methyltransferases with to the of the PubMed Scopus Google the of production of and related oxygenated compounds in Mycobacterium Draper P. J. Microbiol. Google and other mycobacterial C. Lanéelle M.A. Daffé M. H. Lanéelle J. PubMed Scopus Google the and the of these of the other has that these molecules are by the would be a diethylenic that would be by or the to acids a 3Daffé M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). that the mutant produced dicyclopropanated acids as the strain and in data are with the of to the synthesis of acids and involved in the synthesis of oxygenated mycolic the would be altered by the of may a of enzymes are the synthesis of the may from by the of enzymes involved in the of chemical in the of amounts of ethylenic in the hma-inactivated to of oxygenated mycolates of the the that ethylenic fatty may be the biosynthesis of oxygenated mycolates in the and the strain. In the of the hma these putative precursors would be by the to the synthesis of oxygenated mycolates and is the the of the precursors and of the the mutant produced monoethylenic monocyclopropanated (α2) and monocyclopropanated mycolates, the and and carbon the Lanéelle M.A. C. Daffé M. PubMed Scopus Google M. M. PubMed Scopus Google Scholar). of the detailed of mycolic acids, to the that the in oxygenated mycolates are located the and the oxygenated in the other of the that the of an oxygenated function at in the carbon to the of the in of the synthesis of the a the oxygenated should be of the methyltransferases identified in the of M. tuberculosis J. C. K. K. K. K. A. J. K. J. M.A. J. K. J. K. 1998; PubMed Scopus Google Scholar). These enzymes are to be the of in the mycolic that may the and virulence of the tubercle the of a by a double bond in esterifying trehalose the of tubercle and the virulence of the mutant strain Mol. 2000; PubMed Scopus Google Scholar). the lack of production of keto- and methoxymycolates in M. tuberculosis in both a of the permeability and an of virulence of the mutant strain (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). These in to the that the biosynthesis to mycolic acids is the of the most that may represent the of In the identification of putative precursors of oxygenated mycolates should help in the design of that would be as inhibitors of the of the methyltransferases are the their are Smith J. PubMed Scopus Google the inhibitors of may the of other in an that may be or the that the of the from M. M. smegmatis the production by the recipient strain of amounts of acids and small amounts of acids E. Lanéelle M.A. A. Daffé M. Quémard A. Mol. Microbiol. PubMed Scopus Google Scholar). of the gene tuberculosis hma has resulted in the of the production of the oxygenated mycolates in M. the and acids (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). was that the hma gene is involved in the synthesis of oxygenated mycolic acids and that acids are to be precursors of and tuberculosis. mutant strain was found to types of mycolic acids from the that these molecules may represent the precursors of the oxygenated mycolates tuberculosis Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar). the was to the chemical of these of mass spectrometry, NMR spectroscopy, and chemical degradation to the analysis of the of mycolates produced by the mutant several in the of the the mutant strain as mycolates as the that the in these molecules is the of the both the mutant and amounts of dicyclopropanated that the the production of of the mutant produced amounts of a of mycolates, a of monoethylenic monocyclopropanated α-mycolates, and a of monocyclopropanated the ethylenic the growth of the that from of the mutant strain with the wild-type resulted in the disappearance of the types of mycolates and the production by the strain of the types of mycolates of the strain. of the hma gene in M. smegmatis led to the lowering of diethylenic of the recipient strain and the production of keto- and hydroxymycolates. that the in the structure of mycolates of the mutant are to the of the hma gene and the biosynthesis of mycolic of the related to the biosynthesis of mycolic acids is the that to the of the oxygenated at the of the of substrates to oxygenated chemical a E. Rev. Scopus Google Scholar, C. J. Lanéelle Lanéelle M.A. PubMed Scopus Google a to an as known or an ethylenic in a should in the as function A. PubMed Scopus Google Scholar). Because in the hma-inactivated is to that the ethylenic double bond in the of the mutant strain is the of In the the the of the ethylenic bond be a or a In both an would be to the keto- or the the of in the are to found in oxygenated mycolates of the strain and in the of the strain the in and oxygenated mycolates Lanéelle M.A. C. Daffé M. PubMed Scopus Google Scholar, M. H. H. M. PubMed Scopus Google and to be to the of the methyltransferases with to the of the PubMed Scopus Google Scholar). the of production of and related oxygenated compounds in Mycobacterium Draper P. J. Microbiol. Google and other mycobacterial C. Lanéelle M.A. Daffé M. H. Lanéelle J. PubMed Scopus Google the and the of these of the other has that these molecules are by the would be a diethylenic that would be by or the to acids a 3Daffé M. Draper P. Adv. Microbiol. Physiol. 1998; 39: 131-203Crossref PubMed Google Scholar). that the mutant produced dicyclopropanated acids as the strain and in data are with the of to the synthesis of acids and involved in the synthesis of oxygenated mycolic the would be altered by the of may a of enzymes are the synthesis of the may from by the of enzymes involved in the of chemical in the of amounts of ethylenic in the hma-inactivated to of oxygenated mycolates of the the that ethylenic fatty may be the biosynthesis of oxygenated mycolates in the and the strain. In the of the hma these putative precursors would be by the to the synthesis of oxygenated mycolates and is the the of the precursors and of the the mutant produced monoethylenic monocyclopropanated (α2) and monocyclopropanated mycolates, the and and carbon the Lanéelle M.A. C. Daffé M. PubMed Scopus Google M. M. PubMed Scopus Google Scholar). of the detailed of mycolic acids, to the that the in oxygenated mycolates are located the and the oxygenated in the other of the that the of an oxygenated function at in the carbon to the of the in of the synthesis of the a the oxygenated should be of the methyltransferases identified in the of M. tuberculosis J. C. K. K. K. K. A. J. K. J. M.A. J. K. J. K. 1998; PubMed Scopus Google Scholar). These enzymes are to be the of in the mycolic that may the and virulence of the tubercle the of a by a double bond in esterifying trehalose the of tubercle and the virulence of the mutant strain Mol. 2000; PubMed Scopus Google Scholar). the lack of production of keto- and methoxymycolates in M. tuberculosis in both a of the permeability and an of virulence of the mutant strain (1Dubnau E. Chan J. Raynaud C. Mohan V.P. Lanéelle M.A. Yu K. Quémard A. Smith I. Daffé M. Mol. Microbiol. 2000; 36: 630-637Crossref PubMed Scopus (253) Google Scholar). These in to the that the biosynthesis to mycolic acids is the of the most that may represent the of In the identification of putative precursors of oxygenated mycolates should help in the design of that would be as inhibitors of the of the methyltransferases are the their are Smith J. PubMed Scopus Google the inhibitors of may the of other in an that may be or the are to the and Quémard and the of and in the