广西眼镜王蛇毒两种酸性磷脂酶A_2的cDNA克隆及序列分析  

Cloning and Sequence Analysis of cDNAs Encoding Two Acidic PLA_2 from venom of Ophiophagus hannah (King Cobra), Guangxi Species

作　　者：王秋雁[1] 舒雨雁[2] 庄茂辛[2] 林政炯[3] 

机构地区：[1]广西医科大学一附院临床实验中心,南宁530021 [2]广西医科大学蛇毒研究所,南宁530021 [3]中国科学院生物物理研究所

出　　处：《生物化学与生物物理学报》2001年第3期340-344,共5页

基　　金：国家自然科学基金资助项目!No .39970 174&&

摘　　要：从广西眼镜王蛇毒腺中提取总RNA ,利用RT PCR进行体外扩增 ,获得磷脂酶A2 基因 (PLA2 ) ,克隆至PUCm T载体中 ,筛选出编码两种酸性PLA2 (命名为APLA2 1和APLA2 2 )的基因 ,经双向测序测定了它们基因的全序列 ,由此推导出编码的氨基酸序列 ,其中APLA2 1的N端 15个氨基酸残基序列同其蛋白质直接测序的结果完全一致。利用计算机软件推算出它们的等电点与实际测定的等电点较为吻合。同源性比较表明 ,APLA2 1与福建眼镜王蛇和台湾眼镜王蛇毒PLA2 成熟肽同源性极高 ,而APLA2 2与它们的同源性相对较低 ,并且APLA2 2与APLA2 1及其他两种眼镜王蛇毒PLA2 分子结构中有一个显著的差别即少一个 6 2～ 6 6位的“胰腺环” 。Total RNA was extracted from venom glands of Ophiophagus hannah, Guangxi species. The cDNAs encoding PLA 2 were amplified by RT PCR and cloned into the PUCm T vector. The positive clones encoding two acidic PLA 2(APLA 2 1 and APLA 2 2) were selected and bidirectionally sequenced. Their complete amino acid sequences were deduced and found to be identical to the known amino acid sequences. Their isoelectric points calculated by computer agreed with the values determined with their protein. Homology analysis indicated that the mature peptide of APLA 2 1 had high homology with PLA 2 from venoms of Ophiophagus hannah, Fujian and Taiwan species, but APLA 2 2 had lower homology. The most striking difference between APLA 2 2 and other PLA 2 from Ophiophagus hannah venoms is the missing of a extra “pancreatic loop” at residues 62—66 in APLA 2 2, and it may be related to their species evolution and biological activity.

关 键 词：眼镜王蛇 磷脂酶A2 基因克隆 蛇毒 

分 类 号：Q55[生物学—生物化学]