Institute of Biological Chemistry, Academia Sinica, Taipei, Taiwan.
J Proteomics. 2013 Aug 26;89:141-53. doi: 10.1016/j.jprot.2013.06.012. Epub 2013 Jun 21.
This study deciphers the geographic variations of king cobra (Ophiophagus hannah) venom using functional proteomics. Pooled samples of king cobra venom (abbreviated as Ohv) were obtained from Indonesia, Malaysia, Thailand, and two provinces of China, namely Guangxi and Hainan. Using two animal models to test and compare the lethal effects, we found that the Chinese Ohvs were more fatal to mice, while the Southeast Asian Ohvs were more fatal to lizards (Eutropis multifasciata). Various phospholipases A2 (PLA2s), three-finger toxins (3FTxs) and Kunitz-type inhibitors were purified from these Ohvs and compared. Besides the two Chinese Ohv PLA2s with known sequences, eight novel PLA2s were identified from the five Ohv samples and their antiplatelet activities were compared. While two 3FTxs (namely oh-55 and oh-27) were common in all the Ohvs, different sets of 3FTx markers were present in the Chinese and Southeast Asian Ohvs. All the Ohvs contain the Kunitz inhibitor, OH-TCI, while only the Chinese Ohvs contain the inhibitor variant, Oh11-1. Relative to the Chinese Ohvs which contained more phospholipases, the Southeast Asian Ohvs had higher metalloproteinase, acetylcholine esterase, and alkaline phosphatase activities.
Remarkable variations in five king cobra geographic samples reveal fast evolution and dynamic translational regulation of the venom which probably adapted to different prey ecology as testified by the lethal tests on mice and lizards. Our results predict possible variations of the king cobra envenoming to human and the importance of using local antivenin for snakebite treatment.
本研究采用功能蛋白质组学方法解析眼镜王蛇（Ophiophagus hannah）毒液的地理变异。从印度尼西亚、马来西亚、泰国和中国的两个省份广西和海南收集了眼镜王蛇毒液（简称 Ohv）的混合样本。使用两种动物模型测试和比较致死效应，我们发现中国的 Ohv 对小鼠的致死性更强，而东南亚的 Ohv 对蜥蜴（Eutropis multifasciata）的致死性更强。从这些 Ohv 中纯化了各种磷脂酶 A2（PLA2）、三指毒素（3FTx）和 Kunitz 型抑制剂，并进行了比较。除了两种已知序列的中国 Ohv PLA2 外，还从五个 Ohv 样本中鉴定了 8 种新的 PLA2，并比较了它们的抗血小板活性。虽然两种 3FTx（即 oh-55 和 oh-27）存在于所有 Ohv 中，但中国和东南亚 Ohv 中存在不同的 3FTx 标志物。所有 Ohv 均含有 Kunitz 抑制剂 OH-TCI，而只有中国 Ohv 含有抑制剂变体 Oh11-1。与含有更多磷脂酶的中国 Ohv 相比，东南亚 Ohv 具有更高的金属蛋白酶、乙酰胆碱酯酶和碱性磷酸酶活性。
五个眼镜王蛇地理样本的显著变异揭示了毒液的快速进化和动态翻译调控，这可能适应了不同的猎物生态，这可以从对小鼠和蜥蜴的致死测试中得到证明。我们的研究结果预测了人类可能会受到眼镜王蛇毒液的影响，并且使用当地抗蛇毒血清治疗蛇咬伤的重要性。
