Fogolari F, Zuccato P, Esposito G, Viglino P
Dipartimento Scientifico Tecnologico, University of Verona, 37100 Verona,
Biophys J. 1999 Jan;76(1 Pt 1):1-16. doi: 10.1016/S0006-3495(99)77173-0.
Electrostatics plays a key role in many biological processes. The Poisson-Boltzmann equation (PBE) and its linearized form (LPBE) allow prediction of electrostatic effects for biomolecular systems. The discrepancies between the solutions of the PBE and those of the LPBE are well known for systems with a simple geometry, but much less for biomolecular systems. Results for high charge density systems show that there are limitations to the applicability of the LPBE at low ionic strength and, to a lesser extent, at higher ionic strength. For systems with a simple geometry, the onset of nonlinear effects has been shown to be governed by the ratio of the electric field over the Debye screening constant. This ratio is used in the present work to correct the LPBE results to reproduce fairly accurately those obtained from the PBE for systems with a simple geometry. Since the correction does not involve any geometrical parameter, it can be easily applied to real biomolecular systems. The error on the potential for the LPBE (compared to the PBE) spans few kT/q for the systems studied here and is greatly reduced by the correction. This allows for a more accurate evaluation of the electrostatic free energy of the systems.
静电学在许多生物过程中起着关键作用。泊松 - 玻尔兹曼方程（PBE）及其线性化形式（LPBE）可用于预测生物分子系统的静电效应。对于具有简单几何形状的系统，PBE和LPBE的解之间的差异是众所周知的，但对于生物分子系统则了解较少。高电荷密度系统的结果表明，LPBE在低离子强度下以及在较小程度上在高离子强度下的适用性存在局限性。对于具有简单几何形状的系统，非线性效应的起始已被证明由电场与德拜屏蔽常数的比值决定。在本工作中，该比值用于校正LPBE结果，以便相当准确地重现从具有简单几何形状的系统的PBE获得的结果。由于校正不涉及任何几何参数，因此可以很容易地应用于实际的生物分子系统。对于此处研究的系统，LPBE（与PBE相比）的电势误差跨越几个kT/q，并且通过校正大大降低。这使得能够更准确地评估系统的静电自由能。
