特异种质烟草HZNH的Fe-SOD基因的克隆与表达

超氧化物歧化酶(superoxidedismutase,SOD)是一种广泛存在于动物、植物、微生物体内的金属酶,按其结合的金属性离子可分为Fe SOD、Mn SOD和CuZn SOD三种,它们通过催化超氧阴离子自由基O·-2发生歧化反应,达到清除O·-2的效果,具有防御氧毒性、增强机体抗辐射损伤能力、防衰老,治疗某些肿瘤、炎症、自身免疫疾病等功效,在农业、医药、食品、化工等产业中的应用前景广阔,因此广受国内外科研工作者的关注和重视1].而试图通过转SOD基因技术来培育高抗逆农作物新品种和基因克隆与表达技术来实现SOD的大规模发酵生产,已成为国内外SOD…

Cloning and Expression of Fe-SOD Gene from a Native Chinese Tobacco Variety HZNH

A new Fe-SOD gene from a native Chinese tobacco germplasm namely HZNH has been successfully cloned and expressed. Full-length cDNA sequences of the Fe-SOD gene was obtained by employing the 5′ and 3′end RACE method from the HZNH′s cDNA library. The full sequence was 1145 bp in length, including 170 bp of 5′untranslated region, 288 bp of 3′untranslated region and 687 bp of coding region. The coding region encoded a peptide of 228 amino acid residues, in which there was a signal peptide with 26 amino acids and a mature peptide of 202 amino acids. The full-length cDNA sequence was compared with all other reported plants' Fe-SOD genes'. The result of Blast analysis showed that they shared high homology(>80%) ,the highest one was to N. plumbaginifolia's with the homology as high as 97.69%. This cDNA was constructed into the prokaryotic expression vector, pQE30a/FeSOD, and transformed into E.coli M15 which was induced with IPTG. SDS-PAGE showed that 27 kD proteins was expressed. The soluble proteins showed the Fe-SOD enzyme activities on PAGE-based isozyme spectrum indicating that this expressed soluble protein is indeed the Fe-SOD enzyme.