Cation enrichment in the ion atmosphere is promoted by local hydration of DNA.
Cation enrichment in the ion atmosphere is promoted by local hydration of DNA.
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DOI：
10.1039/d1cp01963e
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发表时间：
2021-10-20
期刊：
影响因子：
--
通讯作者：
Havenith M
中科院分区：
文献类型：
--
作者：
Ma CY;Pezzotti S;Schwaab G;Gebala M;Herschlag D;Havenith M
静电相互作用是核酸结构和功能的核心，包括它们的折叠、凝聚以及与蛋白质和其他带电分子的相互作用。这些相互作用受到核酸周围离子的深刻影响，这些离子是所谓的离子大气的组成部分。在这里，我们报告了在30-500 cm−1频率范围内对24 bp DNA在一系列碱卤化物（NaCl, NaF, KCl， CsCl和CsF）电解质溶液中溶解的精确傅里叶变换-太赫兹/远红外（FT-THz/FIR）测量，这些溶液对离子气氛的变化敏感。在70-90 cm−1的频率范围内，通过观察Na+、K+和Cs+的阳离子模式，实验检测了离子大气中的阳离子过剩。基于MD模拟，我们提出阳离子过剩的大小（这是盐特异性的）取决于电解质扰乱DNA界面水网络的能力：在NaF气氛中，离子比NaCl电解质更能降低水与DNA之间的相互作用强度。在这里，我们明确考虑了溶剂对离子大气中化学势的贡献：DNA水合层中结合水分子数量的减少与密度波动的增强相关，这降低了离子水合的自由能成本，从而促进了离子在DNA大气中的进一步积累。我们认为考虑局部溶剂化对于理解离子大气是至关重要的。离子大气中的静电相互作用超出了连续介质模型。相反，离子和DNA的水合作用对大气和自由能的组成至关重要。
Electrostatic interactions are central to the structure and function of nucleic acids, including their folding, condensation, and interaction with proteins and other charged molecules. These interactions are profoundly affected by ions surrounding nucleic acids, the constituents of the so-called ion atmosphere. Here, we report precise Fourier Transform-Terahertz/Far-Infrared (FT-THz/FIR) measurements in the frequency range 30–500 cm−1 for a 24-bp DNA solvated in a series of alkali halide (NaCl, NaF, KCl, CsCl, and CsF) electrolyte solutions which are sensitive to changes in the ion atmosphere. Cation excess in the ion atmosphere is detected experimentally by observation of cation modes of Na+, K+, and Cs+ in the frequency range between 70–90 cm−1. Based on MD simulations, we propose that the magnitude of cation excess (which is salt specific) depends on the ability of the electrolyte to perturb the water network at the DNA interface: In the NaF atmosphere, the ions reduce the strength of interactions between water and the DNA more than in case of a NaCl electrolyte. Here, we explicitly take into account the solvent contribution to the chemical potential in the ion atmosphere: A decrease in the number of bound water molecules in the hydration layer of DNA is correlated with enhanced density fluctuations, which decrease the free energy cost of ion-hydration, thus promoting further ion accumulation within the DNA atmosphere. We propose that taking into account the local solvation is crucial for understanding the ion atmosphere. Electrostatic interaction in the ion atmosphere goes beyond continuum models. Instead, the contribution of hydration of both ions and DNA is crucial for the composition of the atmosphere and the free energy.
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影响因子：
15
作者：
Gebala M;Bonilla S;Bisaria N;Herschlag D
通讯作者：
Herschlag D
影响因子：
8.6
作者：
Das, R;Mills, TT;Pollack, L
通讯作者：
Pollack, L
影响因子：
4.8
作者：
Faber, C;Sticht, H;Rösch, P
通讯作者：
Rösch, P
DOI：
10.1021/jp8001614
发表时间：
2008-07-31
期刊：
The journal of physical chemistry. B
影响因子：
--
作者：
Joung IS;Cheatham TE 3rd
通讯作者：
Cheatham TE 3rd
影响因子：
14.9
作者：
Giambaşu GM;Gebala MK;Panteva MT;Luchko T;Case DA;York DM
通讯作者：
York DM