大肠埃希菌和志贺菌mazef基因搜索及蛋白分子进化分析

目的 对已完成基因组测序的10株大肠埃希菌、6株志贺氏菌和1株未定名肠杆菌进行maze和mazf蛋白的分子进化分析.方法 用biocyc提供的pathway tools(13.5版)搜索已完成基因组测序的10株大肠埃希菌、6株志贺菌和1株未定名肠杆菌毒素mazf编码基因mazf(别名chpa)和抗毒素maze编码基因maze(别名chpr),再用mega4.1软件中的minimum evolution法对maze和mazf蛋白做分子进化分析.结果 共有12株搜索到毒素mazf(编码基因为mazf),11株搜索到抗毒素maze(编码基因为maze),另有5株没有搜索到mazef编码基因.分子进化分析提示大肠埃希菌和志贺菌的maze和mazf的保守性较好.结论 mazef是在原核染色体发现的第一个毒素-抗毒素(ta)系统,但不是每株大肠埃希菌和志贺菌均存在这个系统,有可能存在其他ta系统.mazef缺失株表现为对抗菌约物抵抗,又因mazef介导细菌的细胞程序性死亡,mazef有可能成为抗菌药物的新靶位. abstract： objective to perform molecular evolution analysis of mazef gene in genome sequenced strains of escherichia coli and shigella. methods pathway tools (version 13.5) provided by biocyc was used to search encoding gene mazf of toxin mazf ( chpa) and encoding gene maze of antitoxin maze (chpr) in genome sequenced 10 strains of escherichia coli, 6 strains of shigella and 1 strain of unkown enterobacteria. then minimum evolution method in mega4. 1 software was used to analyze molecular evolution of maze and mazf. results encoding gene mazf of toxin mazf was found in 12 strains, and encoding gene maze of antitoxin maze was found in 11 strains, while neither maze nor mazf was found in rest 5 strains. both maze and mazf had good conservation in molecular evolution analysis. conclusions mazef is the first toxin-antitoxin system found in prokaryotic chromosomes, but not in all strains of escherichia coli and shigella. mazef deletion is associated with antibiotic resistance and it also mediates programmed cell death in bacteria, so mazef might be a new target for antimicrobial agents.

mazef gene searching and molecular evolution in genome sequenced strains of escherichia coli and shigella