江浙蝮蛇蛇毒中性磷脂酶A2的结构模拟研究

从我国江浙蝮蛇蛇毒纯化出的中性磷脂酶Ａ２（ＡＴＸ）不仅具有酶催化活性，还具有突触前神经毒性。用图象模拟和能量极小化及分子动力学方法，根据美国西部菱斑响尾蛇（Ｃ．ａｔｒｏｘ）蛇毒ＰＬＡ２的晶体结构构建了ＡＴＸ二体和单体模型，它们的基本折叠与Ｃ．ａｔｒｏｘＰＬＡ２是很相似的。能量计算表明，二体的总势能比单体相应能量的两倍低２６３．６ｋｃａｌ／ｍｏｌ；ＡＴＸ二体模型中两亚基间的作用与Ｃ．ａｔｒｏｘＰＬＡ

Modeling Study of a Neutral Phospholipase A_2 from the Venom of Agkistrodon halys Pallas

The three-dimensional structure of a neutral phospholipase A2 from the venom of Agkistrodon halys Pallas, designated as Agkistrodotoxin, has been modelled basing on the known X-ray crystal structure of Crotalus atrox venom PLA2, using computer graphics, energy-minimization techniques and molecular dynamic simulation method. It has been shown that the overall three dimentional structure is very similar to that of C. atrox PLA2. The energy calculation shows that the dimer's total energy is 263 .6 kcal/mol, lower than twice of the monomer's energy.The dimer stabilizing interactions of ATX dimeric model are very similar to those of C. atrox venom PLA2. These suggest that the dimer is a more stable form than the monomer. The relationship between the neurotoxicity and the strudcture was also explored and discussed.