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首页> 外文期刊>Chemistry: A European journal >Preorganization and reorganization as related factors in enzyme catalysis: the chorismate mutase case
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Preorganization and reorganization as related factors in enzyme catalysis: the chorismate mutase case

机译：预组织和重组是酶催化中的相关因素：分支酸突变

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In this paper a deeper insight into the chorismate-to prephentate-rearrangement, catalyzed by Bacillus subtilis chorismate mutase, is provided by means of a combination of statistical quantum mechanics/molecular mechanics simulation methods and hybrid potential energy surface exploration techniques. The main aim of this work is to present an estimation of the preorganization and reorganization terms of the enzyme catalytic rate enhancement. To analyze the first of these, we have studied different conformational equilibria of chorismate in aqueous solution and in the enzyme active site. Our conclusion is that chorismate mutase preferentially binds the reactive conformer of the substrate-that presenting structure similar to the transition state of the reaction to be catalyzed-with shorter distances between the carbon atoms to be bonded and more diaxial character. With respect to the reorganization effect, an energy decomposition analysis of the potential energies of the reactive reactant and of the reaction transition state in aqueous solution and in the enzyme shows that the enzyme structure is better adapted to the transition structure. This means not only a more negative electrostatic interaction energy with the transition state but also a low enzyme deformation contribution to the energy barrier. Our calculations reveal that the structure of the enzyme is responsible for stabilizing the transition state structure of the reaction, with concomitant selection of the reactive form of the reactants. This is, the same enzymatic pattern that stabilizes the trnasition structure also promotes those reactant structures closer to the transition structure (i.e., the reactive reactants). In fact, both reorganization and preorganization effects have to be considered as the two faces of the same coin, having a common origin in the effect of the enzyme structure on the energy surface of the substrate.
机译：本文结合统计量子力学/分子力学模拟方法和混合势能面探索技术，对枯草芽孢杆菌分支酸突变酶催化的分支酸至苯甲酸酯的重排有了更深入的了解。这项工作的主要目的是提出对酶催化速率提高的预组织和重组项的估计。为了分析其中的第一个，我们研究了水溶液和酶活性位点中分支酸的不同构象平衡。我们的结论是，分支酸突变酶优先结合底物的反应性构象异构体，该构象异构体的结构类似于要催化的反应的过渡态，所键合的碳原子之间的距离更短，并且具有更多的双轴特性。关于重组效果，在水溶液和酶中对反应性反应物的势能和反应过渡态的能量分解的能量分析表明，酶结构更适合于过渡结构。这不仅意味着在过渡态时带负电荷的静电相互作用能更大，而且对能垒的酶变形贡献较小。我们的计算表明，酶的结构负责稳定反应的过渡态结构，同时选择反应物的反应形式。即，稳定过渡结构的相同酶促模式也促进那些反应物结构更靠近过渡结构（即反应性反应物）。实际上，重组和预组织效应都必须被视为同一枚硬币的两个面，在酶结构对底物能量表面的影响上具有共同的起源。

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