氯化钠促进溶菌酶聚集机制的分子动力学研究

Mechanism study of sodium chloride on lysozyme aggregation investigated by molecular dynamics simulation

氯化钠能够在一定的条件下促进溶菌酶发生聚集,但其具体的作用机制目前还尚不明确.采用分子动力学模拟的方法研究了鸡溶菌酶单体在含500mmol/L NaCl和不含NaCl两种体系中的结构变化.模拟的结果表明:NaCl能够使溶菌酶聚集关键区域(40～110位残基)内二硫键cys76-cys94的结合强度减弱,同时破坏了该区域内的氢键网络,从而导致了蛋白结构的不稳定性;另一方面,NaCl也促使疏水核心发生了一定的扩张,使疏水核心内氨基酸残基的结合变得更加松散,从而促进了溶菌酶分子间的相互作用.

Sodium chloride（NaCl） could induce lysozyme aggregation under some conditions,but the detail mechanism has been poorly understood.In this study,performed 10 ns molecular dynamic simulations to investigate the structure changes of chicken lysozyme monomer when treated with 500 mmol/L NaCl.The simulation results indicated that NaCl could weaken the disulfide bond cys76-cys94 as well as the hydrogen bonding network in the aggregation critical region,which might lead instability of the lysozyme structure.In addition,results also showed that the hydrophobic core had an apparent expanding tendency when treated with NaCl,which might promote the intermolecular interactions between lysozyme monomers.