分子动力学模拟哇巴因对钠钾ATP酶构象的影响  

Molecular Dynamics Simulation of Impact of Na,K-ATPase Conformation Combined with Ouabain

作　　者：方彩云[1] 徐金兵[1] 李娟[2] 方慧生[1] 

机构地区：[1]中国药科大学生命科学与技术学院,江苏南京210009 [2]南京鼓楼医院血液科,江苏南京210008

出　　处：《药物生物技术》2014年第2期131-135,共5页Pharmaceutical Biotechnology

基　　金：国家自然科学基金项目(No.31371399)

摘　　要：通过对钠钾ATP酶及其与哇巴因的复合物进行分子动力学模拟来研究哇巴因对该酶构象的影响,首先利用对接得到复合物,然后在相同环境中模拟酶单体及其复合物。结果显示,哇巴因的结合使酶αM1与αM2向小分子靠拢,酶的A区向P区发生轻微移动。酶活性腔中疏水残基Phe783,Thr797,Val322,Gly319,Ile320,Ile321,Leu125,Ile315,Ala112与哇巴因形成疏水作用,极性残基Asp121,Thr797,Gln111与哇巴因形成氢键。通过复合物与酶单体比较,在复合物中,A区的212TGES215基序loop区与侧翼残基的移动掩埋了磷酸化Asp369残基,使其不能自身水解,妨碍了酶执行其功能时E2与E1构象转变,从而抑制酶的活性,并且激发钙离子介导的信号传导通道。此方法不仅直观的展现出酶构象的变化并且很好的解释了哇巴因抑制该酶的机制,同时得到的数据结论对传统实验进一步研究该酶起到指导性作用。To study the impact of ouabain on the conformation change of Na ＋ , K ＋ -ATPase, a new method based on molecular dynamics simulation was proposed. Firstly, complex can be obtained through docking, then, simulate enzyme monomer and its compounds in the same environment. The results showed that after ouabain binding to Na ＋ , K ＋ -ATPase, αM1 and αM2 of Na ＋ , K ＋ - ATPase move toward to ouabain and the A domain is slightly moving toward to P domain in the E2P：ouabain form;and Hydrophobie residues Phe783 ,Thr797, Val322, Gly319, Ile320, Ile321, Leu125, Ile315, Ala112 in binding pocket form hydrophobic effect with ouabain and polar residues, Asp121, Thr797, Gln111 form hydrogen bonds with ouabain. Comparison of the E2P： ouabain complex with E2P structure, in E2P：ouabain complex ,212 TGES215 loop of A domain and flanking residues bury the phosphorylated Asp369 residue, protecting it against spontaneous hydrolysis. This prevents Eland E2 conformational change necessary for the function of the protein, then inhibit the activity of enzyme and stimulate the calcium ion mediated signaling channel. The method proposed in the paper not only intuitively shows the eonformational changes of Na ＋ , K ＋ -ATPase, but well explains the mechanism of interaction of ouabain and Na ＋ , K ＋ -ATPase, and those data play a guiding role for further study.

关 键 词：哇巴因 钠钾ATP酶 对接 分子动力学模拟 P区 ASP369 

分 类 号：Q811.4[生物学—生物工程]