摘要 根据已知多毛类Alittasuccinea铜锌超氧化物歧化酶(Cu/Zn-SOD)基因序列设计引物，利用同源克隆及RACE方法首次从双齿围沙蚕Perinereisaibuhitensis中克隆得到Cu/Zn-SOD基因全长cDNA序列。结果表明：双齿围沙蚕Cu/Zn-SOD基因cDNA全长870 bp，其中包括156 bp 的5′端非编码区，261 bp 3′端非翻译区和453 bp 开放阅读框，编码150个氨基酸;该蛋白序列具有典型的Cu2+和Zn2+结合位点，并具有两处Cu/Zn-SOD 蛋白家族标签序列。通过生物信息学分析表明，该蛋白属于胞内Cu/Zn-SOD，理论相对分子质量为15 249 900，等电点为5.66，无信号肽和跨膜区，推测为亲水性蛋白。同源性分析表明，双齿围沙蚕Cu/Zn-SOD氨基酸序列与部分软体动物、鱼类和昆虫的Cu/Zn-SOD蛋白序列具有很高的相似性。该研究结果为后续研究Cu/Zn-SOD与环境污染物之间的剂量效应关系奠定了基础，为研究双齿围沙蚕机体的防御机制提供了基础资料。
Abstract: A full length cDNA of Cu/Zn-SOD was firstly cloned in sandwormPerinereisaibuhitensisby homology cloning and RACE techniques based on the partial copper-zinc superoxide dismutase (Cu/Zn-SOD)gene from polychaeteAlittasuccinea. The full length of the cDNA was found to be 870 bp including a 156 bp 5′ untranslated region,a 261 bp 3′ untranslated region and 453 bp open reading frame encoding 150 amino acids. There were typical Cu2+and Zn2+binding sites as well as two Cu/Zn-SOD protein family tag sequences in the deduced protein which was within the intracellular Cu/Zn-SOD with relative molecular mass of 15 249 900 and the isoelectric point of 5.66 by bioinformatic analysis. No signal peptide and transmembrane domain were observed in the deduced protein, indicating that it belonged to the hydrophilic protein. Multiple sequences alignment analysis revealed that the deduced amino acids had high homology to the proteins of partial molluscs, fishes and insects. The findings will provide basis for research of dose-response between gene expression and environmental pollutants, and defense mechanism of the sandworm.
2014, Vol. 29 
