烟草MnSOD cDNA基因的克隆及其在大肠杆菌中的表达

CLONING OF TOBACCO MANGANESE SUPEROXIDE DISMUTASE cDNA GENE AND ITS EXPRESSION IN ESCHERICHIA COLI

烟草锰超氧化物岐化酶 (MnSOD)是一种由核基因编码并定位于线粒体的蛋白质 ,是植物体内清除超氧根阴离子的主要酶类 .采用RT -PCR方法 ,从烟草 (Nicotianatubaccum)中克隆到MnSODcDNA基因 (SodA) ,序列分析结果与文献报告的资料相比 ,核苷酸序列的同源性为 99.9% ,氨基酸序列的同源性为 99.6% .该基因能在原核表达载体 pBV2 2 1中正确表达 ,并表现出SOD酶活性 .

The mitochondrial manganese superoxide dismutase (MnSOD) is an enzyme that can eliminate superoxide radicals and protect plant cells against oxidative stress.MnSOD cDNA gene was cloned from tobacco ( Nicotiana tubaccum ) by RT-PCR (Fig 1).Sequence analysis revealed that the DNA sequence of the gene was 99.9% homology with which has been cloned.Then this gene was cloned into the expression vector pBV221,and subsquently expressed in Escherichia coli (Fig 3).The enzyme activity analysis showed that the expressed protein had SOD activity (Fig 4).