Ensifer alkalisoli YIC4027趋化受体基因的比较及相关蛋白序列分析

Comparison of genes and protein sequence analyses of the chemoreceptors in Ensifer alkalisoli YIC4027

摘要:

[目的] 田菁共生根瘤菌Ensifer alkalisoli YIC4027是从宿主植物田菁的根瘤中分离出来的一株新型高效的固氮菌。本研究对E.alkalisoli的趋化受体基因与其他研究透彻的物种进行比较以及相关蛋白分析。[方法] 利用NCBI的BLAST对E.alkalisoli趋化受体基因进行序列相似性搜索。以Pfam数据库为基础，用HMMR3对甲基化趋化受体蛋白（MCP）进行比较分析。[结果] E.alkalisoli有2个趋化基因簇，共有13个MCP，含有不同的信号传感结构。此外，这些MCPs的胞质结构域除了一个是由40个七肽重复序列组成，其余都是由36个七肽重复序列组成。[结论] 尽管E.alkalisoli的趋化受体与已被广泛研究的物种的趋化受体具有较高的相似性，但仍显示出其特性。通过基因的比对以及相关蛋白的分析，我们能够更好地理解E.alkalisoli是如何通过趋化系统来响应外界变化的。

关键词:E.alkalisoli YIC4027;趋化性;MCP

Abstract:

[Objective] Ensifer alkalisoli YIC4027 is a new type of high-efficiency nitrogen-fixing bacteria isolated from the root nodules of the host plant Sesbania cannabina. This study compared the chemoreceptors genes and related proteins of E. alkalisoli with other well-researched species. [Methods] NCBI protein BLAST was used for searching sequence similarity with default parameter values against the genomes of E. alkalisoli. HMMER3, based on Pfam database, was used for comparative analyses of methyl-accepting chemotaxis protein(MCP). [Results] There were two major chemotaxis clusters and 13 MCP homologs containing diverse signal-sensing architectures in E. alkalisoli. In addition, except that one of the cytoplasmic domains of these MCPs was composed of 40 heptad repeats, the rest were composed of 36 heptad repeats. [Conclusion] Despite the high similarity presented between the chemoreceptors of E. alkalisoli and those of well-studied species, E. alkalisoli shows its own unique characteristics. The classification of these chemotactic pathways by gene comparison and related protein analysis enables us to better understand how E. alkalisoli responds to changes in environment via exquisite signal transductions in chemotaxis system.

Key words:E. alkalisoli YIC4027;chemotaxis;MCP