Interactions of hydration water and biological membranes studied by neutron scattering
Interactions of hydration water and biological membranes studied by neutron scattering
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DOI：
10.1021/jp9912410
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发表时间：
1999-09-23
影响因子：
3.3
通讯作者：
Dencher, NA
中科院分区：
文献类型：
--
作者：
Fitter, J;Lechner, RE;Dencher, NA
为了阐明水合水结构和动力学性质的一般特征以及水合水对生物膜动力学行为的影响，用中子散射技术研究了盐细菌紫膜和牛视网膜盘膜。取向多层膜堆的水化膜被用来测量层状衍射图案和准弹性非相干中子散射作为水合水平，温度和蛋白质/脂质比的函数。这些测量揭示了“第一水合层”与膜表面的强相互作用和平行于膜表面的水性溶剂的降低的自扩散（自扩散系数与过量水相比小约5倍）。蛋白质/脂质复合物的皮秒内部分子运动受到与脂质和膜蛋白相互作用的溶剂量的强烈影响。特别是，脂质和它们吸引溶剂分子的能力对生物膜的“水化诱导的柔性”起着重要作用。在这些测量的基础上，讨论了光驱动质子泵紫膜中细菌视紫红质的水合过程对生物膜功能的影响。
To elucidate general features of structural and dynamical properties of hydration water and the influence of hydration water on the dynamical behavior of biomembranes, purple membranes from halobacteria and disk membranes from bovine retinae have been studied by neutron scattering techniques. Hydrated films of oriented multilamellar membrane stacks were used to measure lamellar diffraction patterns and quasielastic incoherent neutron scattering as a function of hydration level, of temperature, and of the protein/lipid ratio. These measurements revealed a strong interaction of a "first hydration layer" with the membrane surface and a reduced self-diffusion of aqueous solvent parallel to the membrane surface (the self-diffusion coefficient is about 5 times smaller as compared to excess water). The picosecond internal molecular motions of the protein/lipid complex are strongly affected by the amount of solvent interacting with the lipids and the membrane proteins. In particular, the lipids and their ability to attract solvent molecules play an important role for "hydration-induced flexibility" of biomembranes. On the basis of these measurements, the impact of the hydration process on the function of biomembranes is discussed for the light-driven proton pump bacteriorhodopsin in purple membranes.