ELECTROSTATIC EFFECTS IN PROTEINS - COMPARISON OF DIELECTRIC AND CHARGE MODELS
ELECTROSTATIC EFFECTS IN PROTEINS - COMPARISON OF DIELECTRIC AND CHARGE MODELS
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DOI：
10.1093/protein/4.8.903
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发表时间：
1991-12-01
期刊：
影响因子：
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通讯作者：
SOLMAJER, T
中科院分区：
文献类型：
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作者：
MEHLER, EL;SOLMAJER, T
两种方法计算蛋白质中的静电效应进行了比较，并提出了一个分析的依赖关系的计算特性的模型来定义的电荷分布。静电自由能的变化已被计算使用屏蔽库仑势（SCP）与距离相关的有效介电常数模型散装溶剂的影响和有限差分方法来解决泊松-玻尔兹曼（FDPB）方程。计算的性质包括电离基团的离解常数的变化，湮灭表面电荷对金属结合的影响，以及由于电离基团的电荷变化而引起的氧化还原电位的变化。在所考虑的蛋白质中，带电位点相隔3.5-12埃。结果表明，在这个距离范围内的SCP产生的计算值至少是准确的FDPB方程的解决方案所获得的系统研究。此外，在3-5埃的距离范围内，SCP给出了比FDPB方程好得多的结果。这两种方法之间的差异的可能来源进行了讨论。结合常数和氧化还原电位的变化计算了几个标准的电荷集，并得到的值之间的“最佳”和“最坏”的情况下，显示出20-40%的变化。从这项研究中得出的结论是，在大多数应用中，静电自由能的变化可以计算经济和可靠地使用SCP方法与一个单一的功能形式的屏蔽功能。
Two approaches for calculating electrostatic effects in proteins are compared and an analysis is presented of the dependence of calculated properties on the model used to define the charge distribution. Changes in electrostatic free energy have been calculated using a screened Coulomb potential (SCP) with a distance-dependent effective dielectric permittivity to model bulk solvent effects and a finite difference approach to solve the Poisson-Boltzmann (FDPB) equation. The properties calculated include shifts in dissociation constants of ionizable groups, the effect of annihilating surface charges on the binding of metals, and shifts in redox potentials due to changes in the charge of ionizable groups. In the proteins considered the charged sites are separated by 3.5-12 angstrom. It is shown that for the systems studied in this distance range the SCP yields calculated values which are at least as accurate as those obtained from solution of the FDPB equation. In addition, in the distance range 3-5 angstrom the SCP gives substantially better results than the FDPB equation. Possible sources of this difference between the two methods are discussed. Shifts in binding constants and redox potentials were calculated with several standard charge sets, and the resulting values show a variation of 20-40% between the 'best' and 'worst' cases. From this study it is concluded that in most applications, changes in electrostatic free energies can be calculated economically and reliably using an SCP approach with a single functional form of the screening function.