江浙蝮蛇磷脂酶A_2基因的多样性研究  

Research on the Diversity of PLA 2 Gene from Agkistrodon halys Pallas

作　　者：潘华[1] 刘小龙[1] 杨冠珍[1] 周元聪[1] 吴祥甫[1] 

机构地区：[1]中国科学院上海生物化学研究所

出　　处：《生物化学与生物物理学报》1998年第1期91-95,共5页

基　　金：国家自然科学基金

摘　　要：我们利用简并引物从江浙蝮蛇毒腺总ＲＮＡ经ＲＴ－ＰＣＲ扩增磷脂酶Ａ２（简称ＰＬＡ２）基因，并以碱性ＰＬＡ２（Ｂ－ＰＬＡ２）基因为探针，分离出了酸性ＰＬＡ２（Ａ－ＰＬＡ２）和两个未见报道的特征结构类同的基因，分别命名为Ａｓｎ４９－ＰＬＡ２和ＢＡ－ＰＬＡ２。双向测序测定了这组ＰＬＡ２同工酶（除信号肽外）基因的全序列，并由此推导编码的氨基酸序列。其中Ａ－ＰＬＡ２基因编码的氨基酸序列与较早报道的由蛇毒中分离纯化的Ａ－ＰＬＡ２肽的氨基酸序列相比有四处不同；而Ａｓｎ４９－ＰＬＡ２与Ｂ－ＰＬＡ２高度同源（达９５％），但是由于ＰＬＡ２中参与酶促反应的重要残基Ａｓｐ４９突变为Ａｓｎ４９－ＰＬＡ２的Ａｓｎ，可能极大影响该酶的活性；ＢＡ－ＰＬＡ２的Ｎ端１～２４位氨基酸与Ｂ－ＰＬＡ２同源而Ｃ端的７２～１２５位氨基酸序列与Ａ－ＰＬＡ２一致。这组同工酶基因的成功克隆，不仅揭示了ＰＬＡ２结构多样性即可能的基因修饰、重排现象，亦是研究ＰＬＡ２结构功能的良好材料。We used degenerate primers to amplify phospholipase A 2( PLA 2) gene by RT PCR from venom total RNA of Agkistrodon halys Pallas, and screened with B PLA 2 gene as probe. Finally we isolated three cDNAs containing A PLA 2 and two other genes showing similar characteristic structure Asn 49 PLA 2 and BA PLA 2.Their complete sequence was determined by bidirectional sequencing and their amino acid sequence was deduced . The amino acid sequence of A PLA 2 deduced from the cDNA agreed with that determined by protein sequencing except for four residues; Asn 49 PLA 2 and B PLA 2 are very alike(up to 95%), but the Asp 49 PLA 2 of B PLA 2 involved in the enzyme reaction is replaced by Asn 49 of Asn 49 PLA 2.Therefore, it possibly affects the enzyme reaction of Asn 49 PLA 2; The N terminus sequence of BA PLA 2 is highly homologous to B PLA 2, but its C terminus sequence is almost the same as A PLA 2. The successful cloning of these isoenzyme genes not only discloses the structure diversity of PLA 2 (namely DNA modification and recombination), but also provides excellent material for the study of structure function relationship in PLA 2.

关 键 词：蝮蛇 磷脂酶A2 基因 克隆 多样性 

分 类 号：Q343.24[生物学—遗传学] Q556.1