嗜盐古生菌AJ4中BR蛋白基因部分片段和16S rRNA基因序列研究

为了研究分析新疆阿尔金山国家自然保护区阿牙克库木湖嗜盐古生菌物种与细菌视紫红质(bacteriorhodopsin ,BR)蛋白资源 ,对分离纯化到的极端嗜盐古生菌AJ4 ,采用PCR方法扩增出其 16SrRNA基因 (16SrDNA)和编码螺旋C至螺旋G的BR蛋白基因片断 ,并测定了基因的核苷酸序列 .通过BR蛋白部分片段序列分析表明 ,BR蛋白中对于完成质子泵功能以及与视黄醛结合的关键性氨基酸残基均为保守序列 ,位于膜内侧的序列比位于膜外侧的序列更保守 ;基于BR蛋白基因和16SrDNA序列的同源性比较以及 16SrDNA序列的系统发育学研究表明 ,AJ4是Haloarcula属中新成员 .由此建立了一种快速筛选具有新BR蛋白的新嗜盐古生菌的方法 .

Partial Sequence of the Gene for a New BR Protein, and Nucleotide Sequence of 16S rRNA Encoding Gene from a Halophilic Archaeum AJ4

In order to study the species and bacteriorhodopsin (BR) protein resource from Ayakekum Lake in the Altun Mountain National Nature Reserve Region of Xinjiang, a strain of halophilic archaeum AJ4 was isolated. 16S rRNA encoding gene and a part of the gene coding for a BR protein from AJ4 were amplified by PCR, and the nucleotide sequences were determined. The analysis of BR protein fragment showed that those amino acid residues in BR, essential for proton pumping and binding to retinal, are conserved. The results also indicated that the amino acid residues at the cytoplasmic side of membrane are more conserved than those at the external side. On the basis of homology analysis about BR gene and 16S rDNA as well as phylogenetic analysis about 16S rDNA, it was speculated that the strain AJ4 was a new member of the genus Haloarcula. So, a convenient and rapid method for screening a new BR protein from a new halophilic archaeum was established.