江浙蝮蛇磷脂酶A2基因的多样性研究

我们利用简并引物从江浙蝮蛇腺总ＲＮＡ经ＲＰ－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Ａｓｎ＾４８－ＰＡＬ２和ＢＡ－ＰＡＬ２。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

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

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.