马铃薯可溶性淀粉合成酶SSⅢ基因克隆及生物信息学分析

Cloning and Bioinformatic Analysis of Soluble Starch Synthase SSⅢ Gene in Potato

用RT-PCR方法从马铃薯中克隆了可溶性淀粉合成酶SSⅢ基因的cDNA片段,序列分析表明该cDNA片段全长为3967bp,开放阅读框为3693bp,编码1230个氨基酸。核酸序列同源性分析表明,该cDNA与已发表的马铃薯SSⅢ基因(X94400)具有99%同源性,氨基酸序列同源性达98%。应用生物信息学软件对SSⅢ基因分析表明:其编码的蛋白质具有多个磷酸化位点;蛋白质二级结构预测显示,有369个氨基酸可能形成α-螺旋结构,249个氨基酸可能形成β折叠,102个氨基酸可能形成β转角,510个氨基酸可能形成无规则卷曲;通过亚细胞定位可知,它是一种含有75个氨基酸的叶绿体转运肽蛋白。

The cDNA of soluble starch synthase （SS Ⅲ） gene was cloned by RT-PCR from potato. The sequence analysis showed that the full-length of the cDNA was 3 697 bp with a 3 693 bp open reading frame encoded a 1 230 amion acid polypeptide. Homology analysis of the nucleotide sequence and the deduced amino acid sequence showed that the cDNA shared 99% and 98% identity with the published sequence （X94400）, respectively. The analysis ofbioinformatics software showed that the SS Ⅲ protein has several phosphorylation sites, and α helix with 369 amino acids, β sheet with 249 amino acids, β turn with 102 amino acids, and random coil with 510 amino acids in the second structure, which was a kind of chloroplast transit peptide with 75 amino acids.