MOLECULAR MECHANISMS CONTROLLING BACTERIORHODOPSIN

光驱动质子泵细菌视紫红质是最简单的 自然界中的能量转换装置和离子泵。的汇聚点 关于结构、光化学和质子泵浦的信息 细菌视紫红质的特性使其成为一种理想的蛋白质 试着了解控制质子泵的分子机制。 因此，这一应用的重点是单个氨基酸。 在希夫碱附近，来自BR的细菌视紫红质的活性部位 通过它之后经历的变换来实现初始状态 吸收一个光子，当它返回到初始状态时。在……里面 具体地说，将探讨以下四个问题：1)什么 控制希夫碱和初始质子D85的pKa(S) 席夫碱的受体和部分反离子？2)什么 控制暗适应的速率，以及相关的过程，即 末端发色团的热重异构化 光循环？3)。控制(或引起)质子运动的是什么 光循环。例如，席夫碱的PK会改变吗 在光循环过程中？是什么控制了席夫碱的反应速度 去质子化，L到M的转变？4)质子是什么？ 释放组和如何控制质子释放？ 活性部位附近的下列可电离氨基酸为 研究：酪氨酸57和185，精氨酸82和赖氨酸129，以及 席夫碱和天冬氨酸85和212。我们会操纵 不仅是色素的蛋白质部分，而且还有吸光性 使用化学修饰视网膜的发色团。

The light driven proton pump bacteriorhodopsin is one of the simplest energy conversion devices and ion pumps in nature. The convergence of information on the structure, photochemistry, and proton pumping properties of bacteriorhodopsin make it an ideal protein in which to try to understand the molecular mechanisms controlling a proton pump. Thus, the focus of this application is on the individual amino acids near the Schiff base, the active site of bacteriorhodopsin, from bR's initial state through the transformations that it undergoes after absorbing a photon and as it returns to the initial state. In particular, the following four questions will be probed: 1) What controls the pKa(s) of the Schiff base and of D85, the initial proton acceptor and part of the counter ion to the Schiff base? 2) what controls the rate of dark adaptation, and a related process, the rate of thermal reisomerization of the chromophore at the end of the photocycle? 3). What controls (or causes) the proton movements during the photocycle. For example, does the pK of the Schiff base change during the photocycle? What controls the rate of Schiff base deprotonation, the L to M transition? and 4) what is the proton release group and how is proton release controlled? The following ionizable amino acids near the active site will be studied: tyrosine 57 and 185, arginine 82 and lysine 129, as well as the Schiff base and the aspartic acids 85 and 212. We will manipulate not only the protein part of the pigment but also the light-absorbing chromophore using chemically modified retinals.