Roles of Hydration in Protein-Ligand Binding: Passive or Active Participant?

IF 2.8 2区 化学 Q3 CHEMISTRY, PHYSICAL
Kacie A Evans, He Mirabel Sun, Morgan Powers, Carter Lantz, Arthur Laganowsky, Hays Rye, David H Russell
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Abstract

Hydration is a critical yet often underappreciated factor that influences protein dynamics in solution, with direct effects on structure, stability, and interactions such as ligand binding. Native mass spectrometry (nMS) enables the analysis of biomolecules in their solution states, which are shaped by cofactors, osmolytes, ligands, and notably, hydration. Here, we employ variable-temperature electrospray ionization to address a central question in molecular biophysics: does hydration act as a passive background solvent or as an active participant in modulating ligand binding? To investigate these effects, temperature-dependent changes in average charge state (Zavg), ADP equilibrium binding affinities (Ka), and enthalpy-entropy compensation (EEC) for the GroEL single ring mutant (SR1) were collected in both H2O and D2O. Temperature-dependent shifts in Zavg were observed for SR1-ADP complexes in both solvents, indicating protein conformational changes. Differences in nucleotide binding affinities calculated from mole fraction plots determined as a function of concentration between H2O and D2O solutions suggest that hydration plays a role in modulating ligand binding. Changes in hydration can modulate protein conformation and ligand binding affinities, typically reflected in shifts in enthalpy (ΔH) and entropy (-TΔS), while the overall Gibbs free energy (ΔG) remains relatively unchanged. Thermodynamic analysis revealed distinct patterns of EEC in D2O compared to H2O, providing insight into how hydration modulates the SR1(ADP)1-7 interactions. Collectively, these findings support the view that hydration acts as an active participant in ligand binding, with measurable effects on protein conformation, stability, and thermodynamics.

水合作用在蛋白质-配体结合中的作用:被动还是主动?
水合作用是影响溶液中蛋白质动力学的一个关键因素,但经常被低估,它对结构、稳定性和配体结合等相互作用有直接影响。天然质谱(nMS)能够分析溶液状态下的生物分子,这些生物分子由辅因子、渗透物、配体和水合作用形成。在这里,我们采用变温电喷雾电离来解决分子生物物理学中的一个核心问题:水合作用是作为被动的背景溶剂还是作为调节配体结合的主动参与者?为了研究这些影响,我们收集了GroEL单环突变体(SR1)在H2O和D2O中平均电荷态(Zavg)、ADP平衡结合亲和(Ka)和焓熵补偿(EEC)的温度依赖变化。SR1-ADP复合物在两种溶剂中均观察到温度依赖性的Zavg变化,表明蛋白质构象发生了变化。根据摩尔分数图计算出的核苷酸结合亲和力的差异作为H2O和D2O溶液浓度的函数,表明水合作用在调节配体结合中起作用。水合作用的变化可以调节蛋白质的构象和配体的结合亲和性,这通常反映在焓(ΔH)和熵(-TΔS)的变化上,而总体的吉布斯自由能(ΔG)保持相对不变。热力学分析揭示了D2O与H2O中EEC的不同模式,为水合作用如何调节SR1(ADP)1-7相互作用提供了深入的见解。总的来说,这些发现支持了水合作用作为配体结合的积极参与者的观点,对蛋白质的构象、稳定性和热力学具有可测量的影响。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
The Journal of Physical Chemistry A
The Journal of Physical Chemistry A 化学-物理:原子、分子和化学物理
CiteScore
5.20
自引率
10.30%
发文量
922
审稿时长
1.3 months
期刊介绍: The Journal of Physical Chemistry A is devoted to reporting new and original experimental and theoretical basic research of interest to physical chemists, biophysical chemists, and chemical physicists.
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