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 在生物界面间的转移，这是一个对所有生物至关重要的过程， 细胞 平面脂双层被用作细胞间的模型， 脸上 通过脂质双层-水界面的电荷转移， 将通过快速光电方法研究双分子层本身 以及在以前的研究中开发的光电门效应。 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作用 并且允许观察离子运动而不干扰电容性 文物 这些测量和静电计算 膜内的相互作用将被用来解开各种 电荷移动的阶段：界面、跨膜和反向 界面的 我们将使用富勒烯C60作为一种新型的疏水阴离子 电荷载体 特别是，我们将致力于验证我们的离子链 疏水离子跨膜电导假说。的链 交替的阳离子和阴离子可允许离子穿过膜 通过在每一端的单跳，类似于Grotthuss机制， 过量的质子或氢氧根离子在水中的迁移率。 证明了这一点 这一机制将对离子通道的起源产生影响： Chain可以看作是这些渠道的原型。 通道形成肽类似物如天蚕素的合成 和蜂毒肽将被用来了解的分子决定因素， 通道形成和离子门控。 宽带时间分辨脉冲光声方法 在以前的研究中开发，将应用于细菌视紫红质 以及溶液中和界面处的电荷转移反应。 一个主要 目的是确定熵效应的重要性， 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.