ELECTROSTATIC AND HYDRODYNAMIC ORIENTATIONAL STEERING EFFECTS IN ENZYME-SUBSTRATE ASSOCIATION
ELECTROSTATIC AND HYDRODYNAMIC ORIENTATIONAL STEERING EFFECTS IN ENZYME-SUBSTRATE ASSOCIATION
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DOI：
10.1016/s0006-3495(95)79874-5
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发表时间：
1995-07-01
影响因子：
3.4
通讯作者：
MCCAMMON, JA
中科院分区：
文献类型：
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作者：
ANTOSIEWICZ, J;MCCAMMON, JA
用布朗动力学模拟了裂酶的哑铃模型和伸长配体的哑铃模型之间的扩散相遇。模拟考虑了分子之间的静电和流体动力学相互作用。结果表明，列入流体动力相互作用到模拟的主要影响是在速率常数的整体下降。流体动力学取向的影响是适度的大小，这里考虑的系统。它们表现出的速度常数的变化时，有利于流体动力学相互作用的扩散遇到的静电相互作用的整体强度的函数相比，有利于静电相互作用。静电相互作用通过改变底物向酶的漂移速度来改变流体动力学扭矩。我们的结论是，仅涉及酶与其配体之间的静电相互作用的模拟可能会产生一些速率常数（例如，20%）太高，但提供了酶-配体遭遇中的取向操纵效应的现实描述。
Diffusional encounters between a dumbbell model of a cleft enzyme and a dumbbell model of an elongated ligand are simulated by Brownian dynamics. The simulations take into account electrostatic and hydrodynamic interactions between the molecules. It is shown that the primary effect of inclusion of hydrodynamic interactions into the simulation is an overall decrease in the rate constant. Hydrodynamic orientational effects are of modest size for the systems considered here. They are manifested when changes in the rate constants for diffusional encounters favored by hydrodynamic interactions are compared with those favored by electrostatic interactions as functions of the overall strength of electrostatic interactions. The electrostatic interactions modify the hydrodynamic torques by modifying the drift velocity of the substrate toward the enzyme. We conclude that simulations referring only to electrostatic interactions between an enzyme and its ligand may yield rate constants that are somewhat (e.g., 20%) too high, but provide realistic descriptions of the orientational steering effects in the enzyme-ligand encounters.