MOLECULAR MECHANISMS CONTROLLING BACTERIORHODOPSIN

控制细菌视紫红质的分子机制

• 批准号: 6835512
• 负责人: THOMAS G EBREY
• 金额: $ 8.93万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-02-01 至 2005-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6835512
• 关键词: Schiff bases; acidity /alkalinity; bacterial pigment; bacteriorhodopsins; chemical kinetics; chromophore; cis trans isomerization; hydrogen ions; ion transport; membrane proteins; molecular dynamics; molecular site; photochemistry; protein transport; protonation

Bacteriorhodopsin is probably the simplest biological energy transducer. It uses light energy, absorbed by a small 26kD protein, to transport protons across the cell membrane. A great deal of progress has been made on tracing out the pathway of the protons across the cell membrane - the "what happens" kinds of questions are close to being solved and we propose a number of experiments to clarify the proton release part of this process. We have now started to make some progress on the next level of questions - proposing some definite hypotheses about the mechanisms of the proton transfer processes and chromophore isomerization - the "how things happen" kinds of questions. We are poised to exploit a major finding from our lab, that the coupling of the pK's of two protonatable groups can explain why proton transfer from the protonated Schiff base to its counter ion can lead to the release of a proton from a group ca. 20 Angstrom units away from the initial proton transfer. We also have developed new methods for determining the effects of mutations of the residues in bR on the proton transfer process -by their effect on the coupling of the pK's of the proton transfer groups. The appearance of high resolution structures will continue to make the functional experiments we propose on bacteriorhodopsin more and more important, as bacteriorhodopsin continues to establish itself as a classic system to study some fundamental questions in biology.

细菌视紫红质可能是最简单的生物能量转换器。 它利用光能，被一个小的26 kD蛋白质吸收， 质子穿过细胞膜。 取得了很大的进展， 追踪质子穿过细胞膜的路径 - “发生了什么”这类问题即将得到解决， 我们提出了一些实验来澄清质子释放部分 这个过程。我们现在已经开始在下一个方面取得一些进展 问题的水平-提出一些明确的假设 质子转移过程和发色团的机理 异构化-“事情是如何发生的”这类问题。 我们 准备利用我们实验室的一个重大发现， 两个可质子化基团的pK可以解释为什么质子从 质子化席夫碱与其抗衡离子的反应可以导致释放出 质子来自Ca组。距离初始质子20埃单位 转移 我们还开发了新的方法来确定 bR残基突变对质子转移的影响 过程-通过它们对质子的pK的耦合的影响 转移组。 高分辨率结构的出现将 继续进行我们提出的功能实验， 细菌视紫红质越来越重要， 继续确立自己作为一个经典的系统，研究一些 生物学的基本问题。