为什么是锌?锌指蛋白质金属键合专一性的密度泛函活性理论研究

摘要

A density functional reactivity theory study has been carried out to elucidate the metalbinding specificity of zinc finger proteins.Three different zinc-finger motif models,denoted by MS4-xNx(where M =divalent metal ions such as Mg,Ca,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,and Zn,S represents the histidine residue,N stands for the cysteine residue,and x =0,1,2).Results from all these model systems exhibit one unique feature of the zinc-finger motif when the zinc divalent cation is bonded.That is,the Zn-bonded complex is both most stable and at the same time most reactive.This seamless combination of two often contradictory properties of a molecular system,stability and reactivity,explains the remarkable metal-binding specificity of the zinc-finger proteins.%采用密度泛函活性理论研究了以锌指蛋白为基础建立的3种锌指模型,MS4-xNx(M为二价金属离子Mg,Ca,Sc,Ti,V,Cr,Mn,Fe,Co,Ni,Cu,Zn；S和N分别代表组氨酸和半胱氨酸残基；x=0,1,2),并探讨了其金属结合特异性.结果表明,当锌离子参与键合时,体系既表现出最大稳定性,同时又显示出最大反应活性.这种同时把稳定性和反应活性有机地结合于一体的特质清楚地说明了锌指蛋白质分子对金属锌离子键合的专一性.