CHARGE TRANSFER ACROSS INTERFACES OF BIOLOGICAL SYSTEMS

研究了脂双层-水界面的性质 通过观察光生电荷转移的动力学 在界面上发生逆向反应 以及产物的跨膜运动。 电 测量直接探测电荷转移， 亚纳秒时间分辨率和埃（德拜长度） 距离表面。 光反应的独特能力， 在亚纳秒的时间内转移这种电荷， 一个前所未有的时间范围，大约十个数量级。 的 研究的目的是获得有关电力和 在界面上的其他电势，在分子运动上， 界面的粘度和离子气氛的弛豫 在这些带电的界面上。 此信息通过以下方式获得： 详细分析了反应动力学与不同的 带电或极性脂质和各种带电或极性反应物。 带电物质穿过双层的渡越时间将为 直接测量，试图解决 文学 这些测量结果将用于研究 修饰的膜离子通道中的电荷转移， 细菌视紫红质和光合反应中心。 的 目的将是了解的分子决定因素， 通过直接测量电荷运动来进行电荷转移。 测量热力学性质的新方法 光化学循环的动力学分解的热形成， 如在视紫红质、细菌视紫红质和 光合反应中心将被开发。 他们将 将光声技术扩展到纳秒级 时间范围和使用一种新的方法的基础上的变化，离子 电导率

The properties of the lipid bilayer-water interface will be studied by observing the kinetics of photo-generated charge transfer across the interface, of ensuing reverse reaction at that interface and of transmembrane movement of products. Electrical measurements directly probe the charge transfer with subnanosecond time resolution and angstrom (Debye length) distance from the surface. The unique ability of photoreactions to transfer this charge in sub-nanosecond times allows the study of an unprecedented time range, some ten orders of magnitude. The study will be aimed at obtaining information on the electrical and other potentials at the interface, on the molecular motion or viscosity of the interface and on the relaxation of ion atmospheres at these charged interfaces. This information is obtained by detailed analysis of the kinetics of reactions with differently charged or polar lipids and a variety of charged or polar reactants. The transit time of charged species across bilayers will be directly measured in attempts to resolve discrepancies in the literature. These measurements will be applied to the study of charge transfer in modified membrane ion channels, in bacteriorhodopsin and in photosynthetic reaction centers. The aim will be to understand the molecular determinants of the charge transfer by direct measure of the charge movements. New methodologies to measure the thermodynamic properties via kinetically resolved heat formation of photochemical cycles such as occur in phototransduction in rhodopsin, bacteriorhodopsin and photosynthetic reaction centers will be developed. They will be the extension of photoacoustic methodology to the nanosecond time range and the use of a novel method based on changes in ionic conductivity.