Conformational Dynamics of Rhodopsin and Bacteriorhodopsin

荧光偏振和能量转移用于探测 两种光激活蛋白的构象动力学， 视紫红质和细菌视紫红质。 多年来，这些 蛋白质为受体提供了重要的模型系统 作用和离子传输。 的目标 本研究旨在研究蛋白质柔性的变化 是构象转变的结果。 这些系统 由于易于 利用光诱导转变。 这些实验应该 提供了蛋白质动力学如何影响 构象转变 相寿命谱是 用于测量荧光能量转移的变化， 细菌视紫红质的荧光偏振 通过它的质子泵光循环。 这种新颖技术 将允许发色团视网膜的位置变化， 监测毫秒级存在的中间体 时间尺度 在视紫红质的工作中，荧光标记是 连接到位于羧基尾部的位点， 被认为是将尾巴锚在膜上。 膜 该网站的位置将使用 荧光能量转移 荧光各向异性 测量将被用来表征运动的 “拴尾巴” 最后，理论模型将 研究提供分子动力学和 构象变化

Fluorescence polarization and energy transfer is used to probe the conformational dynamics of two light-activated proteins, rhodopsin and bacteriorhodopsin. Over the years, these proteins have provided important model systems for receptor action and ion transport, respectively. The goal of the present study is to investigate changes in protein flexibility as a result of conformational transitions. These systems are especially convenient for this purpose because of the ease of inducing transitions with light. These experiments should provide unique information on how protein dynamics influence conformational transitions. Phase lifetime spectroscopy is used to measure changes in fluorescence energy transfer and fluorescence polarization in bacteriorhodopsin as it proceeds through its proton-pumping photocycle. This novel technique will allow changes in position of the chromophore, retinal, to be monitored for intermediates which exist on the millisecond time scale. In the rhodopsin work, fluorescence labels are attached to a site located on the carboxyl tail which is thought to anchor the tail to the membrane. The membrane location of the this site will be established using fluorescence energy transfer. Fluorescence anisotropy measurements will be used to characterize the motion of the "tethered tail". Finally, theoretical models will be investigated to provide link between molecular dynamics and conformational changes.