Role of Hydration Force in the Self-Assembly of Collagens and Amyloid Steric Zipper Filaments

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• 作者：Krishnakumar M. Ravikumar ; Wonmuk Hwang
• 刊名：Journal of the American Chemical Society
• 出版年：2011
• 出版时间：August 3, 2011
• 年：2011
• 卷：133
• 期：30
• 页码：11766-11773
• 全文大小：1064K
• 年卷期：v.133,no.30(August 3, 2011)
• ISSN：1520-5126

文摘

In protein self-assembly, types of surfaces determine the force between them. Yet the extent to which the surrounding water contributes to this force remains as a fundamental question. Here we study three self-assembling filament systems that respectively have hydrated (collagen), dry nonpolar, and dry polar (amyloid) interfaces. Using molecular dynamics simulations, we calculate and compare local hydration maps and hydration forces. We find that the primary hydration shells are formed all over the surface, regardless of the types of the underlying amino acids. The weakly oscillating hydration force arises from coalescence and depletion of hydration shells as two filaments approach, whereas local water diffusion, orientation, or hydrogen-bonding events have no direct effect. Hydration forces between hydrated, polar, and nonpolar interfaces differ in the amplitude and phase of the oscillation relative to the equilibrium surface separation. Therefore, water-mediated interactions between these protein surfaces, ranging in character from 鈥渉ydrophobic鈥?to 鈥渉ydrophilic鈥? have a common molecular origin based on the robustly formed hydration shells, which is likely applicable to a broad range of biomolecular assemblies whose interfacial geometry is similar in length scale to those of the present study.