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为了进一步验证广义活性指标的合理性与准确性,本文将其应用到了大分子生物体系中,结合局域硬软酸碱(HSAB)原理,研究酶催化反应的活性序列,即砷酸盐还原酶ArsC(1LJU10～17)和低分子量的磷酸盐还原酶LWMPTPase(1PNT12～18)分别亲核进攻砷酸盐和磷酸盐的所有形式(H3YO4/H2YO4-/HYO42-/YO43-,Y=As/P)的反应活性序列,其中,广义局域软度由有限差分近似下的从头计算B3LYP/6-311+G(d,p)方法和直接的ABEEMσπ方法获得.随着底物的负电荷不断增大,体系的整体软度和中心原子的局域软度均变得更软,砷酸盐及其还原酶也比磷酸盐及其还原酶要软.利用广义局域软度结合软度的匹配规则,可知随着底物负电荷的逐渐增加,原子个数较大的酶与底物之间的反应活性不断升高,并且-2价的阴离子(HAsO42-和HPO42-)能够在溶液中稳定存在.所预测的活性序列与实验所测得的结果是相一致的,可见,广义局域软度在预测分子间活性方面能够给出合理的预测.然而,原局域软度结合软度的匹配原则在预测接近真实体系的分子间活性的时候,却得到与实验相反的结果.
In order to further verify the rationality and accuracy of the generalized activity index, this article has been applied to the macromolecular biological system. Combined with the principle of local hard and soft acid (HSAB), we studied the active sequence of enzyme-catalyzed reaction, that is, arsenate reductase ArsC (1LJU10-17) and low molecular weight phosphate reductase LWMPTPase (1PNT12-18) nucleophilicly attack all forms of arsenate and phosphate (H3YO4 / H2YO4- / HYO42- / YO43-, Y = As / P ), In which the generalized local softness is obtained by the ab initio B3LYP / 6-311 + G (d, p) method and the direct ABEEMσπ method under the finite difference approximation. As the negative charge of the substrate increases The overall softness of the system and the local softness of the central atom become softer, and the arsenate and its reductase are also softer than the phosphate and its reductase. By using the matching of the generalized local softness with the softness Rules, we know that as the negative charge of the substrate increases, the reactivity between the larger number of atoms and the substrate increases, and the -2-valent anions (HAsO42- and HPO42-) can stabilize in solution Exists.The prediction of the active sequence and the experimental results are consistent, we can see that the generalized local area Softness can predict the intermolecular activity can give a reasonable prediction.However, the original local softness with the matching principle of softness in the prediction of the real system near the intermolecular activity, but get the opposite result with the experiment.