固氮酶活性中心结构模型的EHMO研究

Structural Information of Nitrogenase Active-Center Clusters Deduced from EHMO Study

应用群分解EHMO程序,研究了基于MoFe-蛋白X射线衍射结果的固氮酶活性中心结构模型.对比和分析了该模型中尚未确定的配体Y分别为S、O、N、C、H和H…H时的总能量和电荷分布等.结果表明Y=O量为有利.本文进一步提出了Y=O的模型在底物活化过程中Y(O)的邻位加氢后作为活性中心吞吐底物与产物窗口的可能作用方式.

Structural models for the nitrogenase FeMo-cofactor based upon the crystallographic analysis of the nitrogenase MoFe-protein were studied by means of the improved method of EHMO calculations , where the interest was focused on the unknown ligand Y of the Ree' s model. The results gained from cases of Y = S, N,O, C, H and H…H suggested that the ligand Y was very like O (model I0 and model X). A probable hydrogenation mechanism (model L) was eventually proposed and discussed in the present paper.