非结核分枝杆菌MmpL家族同源性分析及拓扑结构预测

Homology analysis and function prediction of Mmp L protein family of Nontuberculous Mycobacterion

以非结核分枝杆菌中的胞分枝杆菌、鸟分枝杆菌和耻垢分枝杆菌三个标准株为研究对象,对其Mmp L家族蛋白的同源序列进行相似性分析和功能预测。根据NCBI数据库中分枝杆菌Mmp L蛋白序列进行多重序列比对;用TMHMM Server 2.0在线软件对Mmp L同源序列进行拓扑结构预测;用Interproscan对Mmp L3同源序列进行保守序列和结构域分析。同源分析结果显示:与H37Rv Mmp L家族比较,胞分枝杆菌中没有发现Mmp L2、Mmp L6、Mmp L7、Mmp L8、Mmp L9、Mmp L12和Mmp L13的同源序列;鸟分枝杆菌没有发现Mmp L6、Mmp L7、Mmp L8、Mmp L9、Mmp L12和Mmp L13的同源序列;耻垢分枝杆菌没有发现Mmp L2、Mmp L7、Mmp L9、Mmp L10、Mmp L12和Mmp L13的同源序列,推测可能与菌种差异性有关;拓扑结构预测发现大部分同源序列跨膜次数与H37Rv的对应Mmp L蛋白保持一致,少数序列与H37Rv的对应Mmp L蛋白有较小偏差;保守序列分析发现:与H37Rv比较三个标准株的Mmp L3同源序列有两个膜转运蛋白结构域(MMPL domain),没有固醇敏感多肽区(SSD domain)说明该同源序列有膜转运功能,无SSD介导的胆固醇自我平衡调节、物质运输以及细胞信号转导等功能。研究结果为进一步阐明非结核分枝杆菌的毒力、致病机制和疾病趋势提供基础资料。

To provide evidence for future research on the structures and function of Mmp L protein family in Mycobacterium,this study analyzed homologous sequences,predicted topological structures and predicted conservative domain structures of three Nontuberculous Mycobacterion named M. intracellulare,M. avium subsp. paratuberculosis K- 10 and M. smegmatisstr. According to the homologous sequences three of NTM all have theregion of deletions.For example the M. intracellulare haven＇t Mmp L2,6,7,8,9,12,13,M. avium subsp. paratuberculosis K-10 haven,t Mmp L6,7,8,9,12,13,M. smegmatisstrhaven,t Mmp L2,7,9,10,12,13. According to the topological structures many of the homologous sequences have the same transmembrane and few of them have differenttransmembrane,but all of them have little difference. Conservative sequence analysis found that： compared with H37 Rv three standard strains of Mmp L3 homologous sequences,there were two membrane transport protein structure domain（ MMPL domain）,no sterol- sensing domain（ SSD domain） showd the membrane function,the homologous sequence of no self balance function of intracellular cholesterol levels. The research results further clarify the virulence of M. tuberculosis,pathogenic mechanism and trend of disease to provide basic data.