Objective:To perform molecular evolution analysis of MazEF in genomes of Bifidobacterium. Method:The Protein sequences of MazF in bifidobacterial genomes were obtained by employing the PSI-BLAST search from NCBI. The Protein sequences of MazF encoded by other bacteria were obtained from non-redundant protein database of NCBI. All of the 16 S rRNA sequences used in this study were obtained from non-redundant nucleotide database of NCBI. Clustal χ² and MEGA4 were used to analyze molecular evolution of MazF. Result:The total number of MazF in bifidobacterial genomes were searched of 26 The molecular evolution analysis showed that MazF in bifidobacterial genomes had less conservation;the co-evolution of MazF with the 16 S RNA was only observed in individual species and most homologous analysis results of MazF were not in concordance with 16 S rRNA. Conclusion:MazEF was integrated in bifidobacterial chromosomes through horizontal transfer,which was a part of the non-core genome.%目的：对双歧杆菌属编码的Ⅱ类毒素-抗毒素（TA）系统MazEF进行分子进化分析。方法：利用PSI-BLAST在NCBI中搜索获得双歧杆菌编码的MazF分子序列，在NCBI蛋白数据库、核酸数据库分别下载其他菌属基因组编码的MazF蛋白序列和本研究所涉及菌属的16 S rRNA序列，应用Clustal X2和MEGA4软件对MazF做分子进化分析。结果：共搜索到双歧杆菌株染色体编码毒素蛋白MazF 26个。分子进化分析显示：整个双歧杆菌属的MazF保守性不好；MazF与16 S rRNA的共进化仅在个别菌种中发现，大部分MazF的聚类结果与相应菌种16 S rRNA的聚类结果不同。结论：双歧杆菌中的TA系统MazEF可能是通过基因的水平转移整合入基因组中，属于菌株非核心基因组部分。
展开▼
