泉州湾可口革囊星虫MnSOD全长cDNA的克隆及其生物信息学分析

根据已克隆得到的泉州湾可口革囊星虫MnSOD基因片段（GenBank登录号为EF 062359）,采用5’RACE和3’RACE技术从泉州湾可口革囊星虫体壁中克隆获得MnSOD的cDNA全长序列.该基因全长988bp（GenBank登录号为JX117903）,其中开放阅读框（ORF）长681bp,编码226个氨基酸,是不具跨膜区结构的亲水性稳定蛋白;预测分子量为25.15ku,理论等电点pI为5.96,分子式为C1 128H1 722N314O330S6;α螺旋是其蛋白质二级结构的主要元件,在氨基酸多肽链上有4个Mn结合位点,有3个二硫键位点.四聚体三维结构模型预测结果显示该MnSOD含12个α螺旋和3个β折叠构成一个篮子状的活性中心.泉州湾可口革囊星虫MnSOD基因与其他动物的胞质MnSOD在序列组成、结构及活性位点等方面存在高度相似性.

Cloning and Bioinformatics Analysis of the Full cDNA Sequence of MnSOD from Phascolosoma Esculenta Bodywall

The full sequence of cDNA sequence of MnSOD gene was cloned from phascolosoma esculenta bodywall of Quanzhou bay wetland by the methods of 5＇ RACE and 3＇RACE technique. The MnSOD gene is 988 bp in length, and it has an open reading frame（ORF）of 681 bp, encoding 226 amino acid residues,with protein molecular weight of 25. 15 ku and isoelectric point of 5. 96. The molecular formula of MnSOD is C1 lzs H1 zz2 N314 0330 $6, and it is a hydrophilic, non-transmembrane protein. The main component of MnSOD in secondary structure is alpha-helixs, and there are four Mn-binding sites and 3 disulfide bond on the amino acid residues. 3D structure modeling shows that this kind of MnSOD contains 12 helixes and 3 sheets and has a basketry motif in the enzyme core. Despite sequence variations, the core structure, sequence and activity sites of MnSOD from Phascolosoma esculenta bodywall of Quanzhou Bay wetland are highly similar to those of other animals.