CHARGE TRANSFER ACROSS INTERFACES OF BIOLOGICAL SYSTEMS

这项研究的目的是增加我们对电荷的理解 通过生物界面进行转移，这是一个对所有生物至关重要的过程 细胞。用平面脂质双层作为细胞间相互作用的模型。 面孔。 跨脂双层-水界面的电荷转移和 将通过快速光电方法来研究双层本身 以及在以前的研究中发展出的光门效应。这些 方法允许在亚纳秒时间尺度上直接测量动力学。 光选通方法利用膜内电荷的光生成 并允许在不干扰电容的情况下观察离子运动 手工艺品。这些测量和静电计算 膜内的相互作用将被用来解开各种 电荷运动的三个阶段：界面、跨膜和反向 界面。我们将使用富勒烯C60作为一种新型的疏水阴离子 充电载体。特别是，我们将致力于验证我们的离子链 双分子层疏水离子电导假说。一连串的 阳离子和阴离子的交替可以使离子穿过膜。 通过两端的单个跳跃，类似于格洛特劳斯机制 水中过量的质子或羟基离子的迁移率。这一点的证明 机制对离子通道的起源有影响：离子 Chain可以被视为这些渠道的原型。 天蚕素等通道形成肽类似物的合成 蜂毒素将被用来理解 沟道形成和离子门控。 宽带、时间分辨、脉冲光声学的方法学 在之前的研究中开发的，将应用于细菌视紫红质 溶液中和界面上的电荷转移反应。一位少校 目的将是确定熵效应或 细菌视紫红质的“构象变化”和溶剂化效应 在电荷转移反应中。

The aim of this research is to increase our understanding of charge transfer across biological interfaces, a process vital to all living cells. The planar lipid bilayer is used as the model of cellular inter- faces. The transfer of charge across the lipid bilayer-water interface and across the bilayer itself will be studied by fast photoelectric methods and by the photogating effect developed during previous studies. These methods allow direct measure of kinetics on the subnanosecond time scale. The photogating method uses photogeneration of charge within the membrane and allows ion movement to be observed without interfering capacitative artefacts. These measurements and electrostatic calculations of interactions within the membrane will be used to disentangle the various stages of charge movement: interfacial, transmembrane,and reverse interfacial. We will use the fullerence C60 as a novel hydrophobic anion charge carrier. In particular we will aim at verifying our Ion Chain hypothesis of hydrophobic ion conductance across bilayers. A chain of alternating cations and anions may allow an ion to cross the membrane by a single hop at each end, analagous to the Grotthuss mechanism for excess proton or hydroxyl ion mobilities in water. Proof of this mechanism would have implications for the origin of ion channels: the Ion Chain can be looked upon as a prototype of these channels. Synthesis of analogues of channel forming peptides such as cecropins and melittins will be used to understand the molecular determinants of channel formation and of ion gating. The methodology of wide band, time resolved, pulsed photoacoustics developed during previous studies, will be applied to bacteriorhodopsin and to charge transfer reactions in solution and at interfaces. A major aim will be to ascertain the importance of entropic effects or "conformational changes" in bacteriorhodopsin and of solvation effects in charge transfer reactions.