• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Microbiology >MabA (FabG1), a Mycobacterium tuberculosis protein involved in the long-chain fatty acid elongation system FAS-II
【24h】

MabA (FabG1), a Mycobacterium tuberculosis protein involved in the long-chain fatty acid elongation system FAS-II

机译：MABA（Fabg1），一种涉及长链脂肪酸伸长系统FAS-II的结核分枝杆菌蛋白

获取原文
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

The fatty acid elongation system FAS-II is involved in the biosynthesis of mycolic acids, which are very long-chain fatty acids of the cell envelope specific to Mycobacterium tuberculosis and other mycobacteria. A potential component of FAS-II, the protein MabA (FabG1), was overexpressed and purified. Sedimentation equilibrium analyses revealed that MabA undergoes a dimer to tetramer self-association with a dissociation constant of 22?μM. The protein was detected by Western blotting in a mycobacterial cell-wall extract that produces mycolic acids and in the FPLC FAS-II fraction. MabA was shown to catalyse the NADPH-specific reduction of β-ketoacyl derivatives, equivalent to the second step of a FAS-II elongation round. Unlike the known homologous proteins, MabA preferentially metabolizes long-chain substrates (C8–C20) and has a poor affinity for the C4 substrate, in agreement with FAS-II specificities. Molecular modelling of MabA structure suggested the presence of an unusually hydrophobic substrate-binding pocket holding a unique Trp residue, suitable for fluorescence spectroscopic analyses. In agreement with the enzyme kinetic data, the spectral properties of MabA were different in the presence of the C8–C16 ligands as compared to the C4 ligand. Altogether, these data bring out distinctive enzymic and structural properties of MabA, which correlate with its predilection for long-chain substrates, in contrast to most of the other known ketoacyl reductases.
机译：脂肪酸伸长系统FAS-II参与氰酸的生物合成，这是对结核分枝杆菌和其他分枝杆菌特异的细胞包膜的非常长链脂肪酸。过表达和纯化FAS-II的潜在组分，蛋白质maba（Fabg1）。沉淀平衡分析显示，MABA经历二聚体与四聚体的二聚体，其与22Ωμm的解离常数。通过蛋白质印迹在分枝杆菌细胞 - 壁提取物中检测到产生氰酸和FPLC FAS-II级分的细菌性细胞壁提取物中检测到蛋白质。显示MABA催化β-酮酰基衍生物的β-酮基衍生物的β-酮烷基衍生物的减少，其等于FAS-II伸长圆的第二步骤。与已知的同源蛋白质不同，MABA优先代谢长链底物（C8-C20）并对C4底物具有较差的与FAS-II特异性。 MABA结构的分子建模表明存在具有独特TRP残基的异常疏水的底物结合口袋，适用于荧光光谱分析。与酶动力学数据一致，与C4配体相比，MABA的光谱性质在C8-C16配体存在下不同。总的来说，这些数据带出MABA的独特酶和结构性质，与其对长链基材的偏好相关，与大多数其他已知的酮酰化还原酶相反。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号