The problem of electrostatics in biomolecular systems presents an excellent opportunity for cross-disciplinary science and a context in which fundamental physics is called for to answer complex questions. Due to the large density in biological cells of charged biomacromolecules such as protein factors and DNA, it is challenging to understand quantitatively the electric forces in these systems. Two questions are especially puzzling. First, how is it that such a dense system of charged molecules does not simply aggregate in random and non-functional ways? Second, since some mechanism apparently prevents such aggregation, how is it that binding of biomolecules still occurs so reliably? Recognizing the role of water as a universal solvent in living systems is key to understanding these questions. We present a simplified physical model in which water is regarded as a medium of high dielectric constant that nevertheless exhibits the key features essential for answering the two questions presented. The answer to the first question lies in the strong screening ability of water, which reduces the energy scale of the electrostatic interactions. Furthermore, our model reveals the existence of asymmetric screening, a pronounced asymmetry between the screening for a system with like charges and that for a system with opposite charges, and this provides an answer to the second question.

中文翻译：

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细胞中的电相互作用：水汪汪的“反面”中的不对称筛选

生物分子系统中的静电问题为跨学科科学和需要基础物理学回答复杂问题的背景提供了极好的机会。由于带电生物大分子（如蛋白质因子和 DNA）在生物细胞中的密度很大，因此定量了解这些系统中的电力具有挑战性。有两个问题特别令人费解。首先，如此密集的带电分子系统如何不简单地以随机和非功能方式聚集？其次，既然某种机制显然阻止了这种聚集，那么生物分子的结合如何仍然如此可靠地发生？认识到水作为生命系统中通用溶剂的作用是理解这些问题的关键。我们提出了一个简化的物理模型，其中将水视为高介电常数的介质，但仍显示出回答所提出的两个问题必不可少的关键特征。第一个问题的答案在于水的强大屏蔽能力，它降低了静电相互作用的能级。此外，我们的模型揭示了不对称屏蔽的存在，即具有相同电荷的系统的屏蔽与具有相反电荷的系统的屏蔽之间存在明显的不对称性，这为第二个问题提供了答案。这降低了静电相互作用的能量规模。此外，我们的模型揭示了不对称屏蔽的存在，即具有相同电荷的系统的屏蔽与具有相反电荷的系统的屏蔽之间存在明显的不对称性，这为第二个问题提供了答案。这降低了静电相互作用的能量规模。此外，我们的模型揭示了不对称屏蔽的存在，即具有相同电荷的系统的屏蔽与具有相反电荷的系统的屏蔽之间存在明显的不对称性，这为第二个问题提供了答案。