Interisland evolution of Trimeresurus flavoviridis venom phospholipase A2 isozymes
Interisland evolution of Trimeresurus flavoviridis venom phospholipase A2 isozymes
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DOI：
10.1007/s00239-002-2400-7
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发表时间：
2003-03-01
影响因子：
3.9
通讯作者：
Ohno, M
中科院分区：
文献类型：
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作者：
Chijiwa, T;Yamaguchi, Y;Ohno, M
黄毒蛇栖息在日本西南部岛屿上。从冲绳黄绿假单胞菌蛇毒中分离得到一种磷脂酶A(2)，命名为PL-Y，并从蛋白质和cDNA中测定了其氨基酸序列。PL-Y不能引起水肿。相比之下，来自德岛县黄绿色蛇毒的一种解放军-B，与PL-Y只在三个位置上不同，已知会引起浮肿。从黄绿假单胞菌毒腺中克隆了一种新的聚乳酸(2)，命名为聚乳酸-B‘，与聚乳酸-B类似。黄绿色锥体蛇毒的三种碱性[Asp(49)]PLA(2)同工酶，即PL-Y(冲绳)、PLA-B(德岛)和PLA-B‘(Amami-Oshima)，在N-末端部分相同，但在PI-折叠及其附近有一到四个氨基酸取代。它们之间的这种岛间序列差异是由于隔离在100到200万年的不同环境中造成的，似乎是由于它们的基因点突变的自然选择造成的。此外，在这三个岛屿的黄绿色锥虫毒液中，普遍存在一种主要的解放军(2)，命名为PLA(2)，其cDNA中存在1到3个同义替换。推测该基因是黄绿假单胞菌PLA2同工酶基因的原型，作为主要毒力成分几乎没有发生过非同义突变。基于氨基酸序列的系统发育分析表明，黄曲霉PLA(2)同工酶可分为三类，分别为[ASP(49)]型、[ASP(49)]型和[Lys(49)]型。碱性[ASP(49)]聚乳酸(2)型同工酶可能表现出不同于聚乳酸(2)型和[赖氨酸(49)]聚乳酸(2)型同工酶各自独特的毒性功能。
Trimeresurus flavoviridis snakes inhabit the southwestern islands of Japan. A phospholipase A(2) (PLA(2)) named PL-Y, was isolated from Okinawa T.flavoviridis venom and its amino acid sequence was determined from both protein and cDNA. PL-Y was unable to induce edema. In contrast, PLA-B, a PLA(2) from Tokunoshima T. flavoviridis venom, which is different at only three positions from PL-Y, is known to induce edema. A new PLA(2), named PLA-B', which is similar to PLA-B, was cloned from Amami-Oshima T. flavoviridis venom gland. Three T. flavoviridis venom basic [Asp(49)]PLA(2) isozymes, PL-Y (Okinawa), PLA-B (Tokunoshima), and PLA-B' (Amami-Oshima), are identical in the N-terminal half but have one to four amino acid substitutions in the PI-sheet and its vicinity. Such interisland sequence diversities among them are due to isolation in the different environments over 1 to 2 million years and appear to have been brought about by natural selection for point mutation in their genes. Otherwise, a major PLA(2), named PLA(2), ubiquitously exists in the venoms of T. flavoviridis snakes from the three islands with one to three synonymous substitutions in their cDNAs. It is assumed that the PLA(2) gene is a prototype among T. flavoviridis venom PLA(2) isozyme genes and has hardly undergone nonsynonymous mutation as a principal toxic component. Phylogenetic analysis based on the amino acid sequences revealed that T. flavoviridis PLA(2) isozymes are clearly separated into three groups, PLA(2) type, basic [ASP(49)]PLA(2) type, and [LyS(49)]PLA(2) type. Basic [ASP(49)]PLA(2)-type isozymes may manifest their own particular toxic functions different from those of the isozymes of the PLA(2) type and [LyS(49)]PLA(2) type.