Tracking the putative biosynthetic precursors of oxygenated mycolates of Mycobacterium tuberculosis -: Structural analysis of fatty acids of a mutant strain devoid of methoxy- and ketomycolates
Tracking the putative biosynthetic precursors of oxygenated mycolates of Mycobacterium tuberculosis -: Structural analysis of fatty acids of a mutant strain devoid of methoxy- and ketomycolates
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DOI：
10.1074/jbc.m210501200
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发表时间：
2003-02-28
影响因子：
4.8
通讯作者：
Daffé, M
中科院分区：
文献类型：
--
作者：
Dinadayala, P;Laval, F;Daffé, M
破坏结核分枝杆菌的mma 4基因（重新命名为hma）产生了在酮-和甲氧基分枝杆菌酸盐的合成中有缺陷的突变菌株，其具有改变的细胞壁对小分子的渗透性和在小鼠感染模型中降低的毒力（Dubnau，E.，陈，J.，雷诺角，副总裁莫汉，Laneelle，M.一、Yu，K.，Quemard，A.，史密斯岛，和Daffe，M.（2000）Mol. Microbiol. 36，630-637）。假设突变体会积累M.在结核病中，使用基质辅助激光解吸/电离飞行时间质谱、质子NMR光谱和化学降解技术的组合，对来自HMA灭活菌株的分枝杆菌进行详细的结构分析。这些最专门地由α-分枝菌酸酯组成，其由等量的C-76-C-82二环丙烷化（α（1））和C-77-C-79单烯单环丙烷化（α（2））分枝菌酸酯组成，双键位于“远端”位置。此外，突变菌株产生少量顺式-环氧分枝菌酸盐，结构上与α（2）-分枝菌酸盐相关。将hma失活突变体与野生型基因互补导致新鉴定的分枝菌酸盐消失，并产生M.结核在耻垢分枝杆菌中引入hma基因导致受体菌株的二烯a分枝菌酸盐的降低以及酮和羟基分枝菌酸盐的产生。这些数据表明，长链烯属化合物可能是M.结核由于已知参与分枝菌酸盐生物合成的几种甲基转移酶的产生的缺乏会降低结核杆菌的毒力，因此这些酶的底物的鉴定应该有助于设计M.结核
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., Laneelle, M. A., Yu, K., Quemard, A., Smith, I., and Daffe, 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 alpha-mycolates, composed of equal amounts of C-76-C-82 dicyclopropanated (alpha(1)) and of C-77-C-79 monoethylenic monocyclopropanated (alpha(2)) mycolates, the double bond being located at the "distal" position. In addition, small amounts of cis-epoxymycolates, structurally related to alpha(2)-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 in Mycobacterium smegmatis led to the lowering of diethylenic a 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.