Quantitatively Identifying the Roles of Interfacial Water and Solid Surface in Governing Peptide Adsorption
Quantitatively Identifying the Roles of Interfacial Water and Solid Surface in Governing Peptide Adsorption
复制标题
定量识别界面水和固体表面在控制肽吸附中的作用
DOI：
10.1021/acs.langmuir.8b01189
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发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Sahai Nita
中科院分区：
文献类型：
--
作者：
Xu Zhijun;Yang Xiao;Wei Qichao;Zhao Weilong;Cui Beiliang;Yang Xiaoning;Sahai Nita
了解蛋白质在固体上吸附的分子机制对于其在材料合成和组织工程中的应用至关重要。尽管表面/水界面处的水相已被认为分为三种类型：本体水、中间水相和表面结合水层，但水和表面在确定蛋白质吸附中的作用尚不清楚，特别是在定量水平上。在此，我们提供了一种结合微秒强化采样模拟和力积分的方法，以定量表征水诱导的贡献和肽-表面相互作用对吸附自由能的影响。以羟基磷灰石和石墨烯表面为例，我们展示了不同的界面特征如何主导这两个热力学参数之间微妙的力平衡，从而导致对肽吸附的表面偏好/阻力。具体而言，水层提供了针对肽吸附的持续排斥力，如水诱导的自由能曲线的单调增加所示，而表面-肽相互作用的贡献在热力学上有利于肽吸附。更重要的是，所揭示的吸附机制很大程度上取决于水相的分布，这在建立肽与水层和表面相互作用之间的力平衡方面起着至关重要的作用。对于 HAP 表面，由于中间水相中肽-表面相互作用的控制作用，带电肽对表面表现出很强的结合亲和力。表面结合水层被观察为固体表面对电荷中性肽吸附的生物抗性的根源。然而，石墨烯上优选的肽吸附主要由邻近表面的水层处的表面诱导成分主导。我们的结果进一步阐明，与亲水表面上的观察相反，中间水相显着缩短了表面分散力的有效范围。
Understanding the molecular mechanism of protein adsorption on solids is critical to their applications in materials synthesis and tissue engineering. Although the water phase at the surface/water interface has been recognized as three types: bulk water, intermediate water phase and surface-bound water layers, the roles of the water and surface in determining the protein adsorption are not clearly identified, particularly at the quantitative level. Herein, we provide a methodology involving the combination of microsecond strengthen sampling simulation and force integration to quantitatively characterize the water-induced contribution and the peptide-surface interactions into the adsorption free energy. Using hydroxyapatite and graphene surfaces as examples, we demonstrate how the distinct interfacial features dominate the delicate force balance between these two thermodynamics parameters, leading to surface preference/resistance to peptide adsorption. Specifically, the water layer provides sustained repelling force against peptide adsorption, as indicated by a monotonic increase in the water-induced free energy profile, whereas the contribution from the surface-peptide interactions is thermodynamically favorable to peptide adsorptions. More importantly, the revealed adsorption mechanism is critically dictated by the distribution of water phase, which plays a crucial role in establishing the force balance between the interactions of the peptide with the water layer and the surface. For the HAP surface, the charged peptide exhibits strong binding affinity to the surface, due to the controlling contribution of peptide–surface interaction in the intermediate water phase. The surface-bound water layers are observed as the origin of bioresistance of solid surfaces toward the adsorption of charge-neutral peptides. The preferred peptide adsorption on the graphene, however, is dominated by the surface-induced component at the water layers adjacent to the surface. Our results further elucidate that the intermediate water phase significantly shortens the effective range of the surface dispersion force, in contrast to the observation on the hydrophilic surface.