基于小麦淀粉合成酶SSⅡa氨基酸序列的生物进化分析

Phylogenetic Analysis of Wheat Starch Synthase Based on the Amino Acid Sequence of SSⅡa

选取小麦淀粉合成关键酶SSⅡa,通过生物信息学分析,探究其在进化过程中与其它生物的亲缘关系,看其是否可以作为生物进化的依据。利用克隆得到的小麦SSⅡa基因翻译氨基酸序列,并在NCBI上做BLAST同源比对,并于Swiss Prot非冗余蛋白数据库获得不同生物的同源氨基酸序列进行生物信息学分析。共比较了47种生物的氨基酸序列,其中包括6种藻类、1种苔藓、1种蕨类、1种菌类和38种陆生被子植物。结果显示:小麦淀粉合成酶氨基酸序列与其它生物的同源性为37%-99%,并表现出较高的保守性。通过构建系统进化树,发现淀粉合成酶氨基酸序列可以大体的反映生物进化关系,其氨基酸序列可以用来判定生物进化过程中亲缘关系的远近。

SS Ⅱ a （Starch synthase Ⅱ a） gene is a key gene which is responsible for the wheat amylopectin synthesis,and the cDNA of SS lI a gene was cloned by RT-PCR from wheat. An amino acid sequence of SS Ⅱ a from wheat was obtained and searched in Swiss-prot bank with BLASTp,and we wanted to explore whether it can be used as the basis of biological evolution. All the SS Ⅱ a amino acid sequences obtained were analyzed,including 6 algae,1 moss,1 fern,1 fungus,and 38 angiosperms,which were 47 amino sequences together. Amino acid sequence of SSⅡ a from wheat shared 37%-99% similiarity with other sequences of SS I/a,which partly implied that amino sequence of SSⅡ a showed biggish evolution and conservation. By constructing phylogenetic tree,we also found that SS Ⅱ a amino acid sequence can generally reflect the evolutionary relationship.We could conclude the sequence of SS Ⅱa can be used as the moclecular proof of molecular evolution and phylogenetics.