Bacillus halodurans菌株xynM基因的克隆、表达和序列分析

目的:用2株新分离鉴定的细菌克隆与最近源种(Bacillus halodurans C-125)木聚糖酶基因的同源序列,并对其进行序列分析。方法:根据已发表的近源种(C-125)的保守区序列设计引物,扩增出与其同源的木聚糖酶基因,进而用pQE31载体对该基因进行表达。同时对表达蛋白的三维空间结构进行网络模拟分析,对蛋白同源性进行比对分析。结果:克隆的木聚糖酶基因片段分别为1284bp和1236bp,而且该基因也成功表达;该蛋白是(α/α)6折叠构象,与C-125三者同属于一个分支上。结论:通过分析、表达蛋白编码外切-1,4-β-木聚糖酶,属于M家族。这该新分离菌株木聚糖酶的研究和应用提供了重要线索。

Sequence Analysis, Cloning and Expression of XynM Gene from the Bacillus halodurans Strains

Objective: To clone the xylanase gene from two isolated Bacillus halodurans strans and analyse the sequence. Methods: According to conserved sequence analysis of the nearest species(C-125),a pair of primers were used to amplify and express the genes. And the three-dimentional structure of the two XynM protein was analysed by ExPASy. Meanwhile,hylogenetic tree of Xyn proteins was also made.Results:The BhXJU-1 xyrM (1284bp)and BhXJU-80 (1236bp) xynM geneswere amplified and successfully expressed.And the proteins were (α/α)6 fold. Sequence homology analysis of amino acid showed that the two proteins shared high homology (99%) compared with different species of Bacillus halodurans and they belonged to the same branch of phylogenetic tree. Conclusion: The two proteins encoded endo-1,4-β-xylanase were new members of family M of glycosyl hydrolases. This offered an important clue for the study of the xylanase product of the XJU-1 and XJU-80 species.