猪氨基酰化酶I与底物的分子对接及定点突变验证

Porcine Aminoacylase I Molecular Docking with Substrate and Verification by Site-directed Mutagenesis

氨基酰化酶Ⅰ特异性催化水解N-酰基-L-氨基酸生成L-氨基酸。本研究采用AUTODOCK3.05软件对猪氨基酰化酶Ⅰ与最适底物分子N-乙酰-L-甲硫氨酸进行了模拟对接,并运用定点突变对模拟结果进行验证,为探究此酶的催化机制提供理论依据。对接结果表明,底物结合于锌离子附近的二聚体结构域与催化域的界面上;底物与酶分子的Glu146和Arg348形成重要氢键;底物极性头部与Thr345发生了强烈的相互作用。定点突变后酶动力学参数测定结果与模拟对接结果相符。在结合中,氢键和亲水相互作用发挥了重要作用。

N-acetyl-L-amino acids were specifically hydrolyzed into L-amino acids by aminoacylase Ⅰ. In this work, a molecular docking between porcine aminoacylase Ⅰ and its best substrate （N-aeetyl-L-methionine） was studied to explore their interaction and the catalysis mechanism of aminoacylase I by AUTODOCK 3.05 program, and the re- sult was verified by site-directed mutagenesis. The docking results indicated that the substrate was near Zn2＋ and lo- cated in the interface between the dimeric domain and the catalysis domain; the substrate formed the hrdrogen bonds with Glu146 and Arg348; furthermore, the polar head of the substrate was very close with Thr345. The ki- netic parameters of the mutants were match with the data of our docking, in which hydrogen bond and hydrophilic force played key roles.