MOLECULAR MECHANISMS CONTROLLING BACTERIORHODOPSIN

控制细菌视紫红质的分子机制

• 批准号: 6151075
• 负责人: THOMAS G EBREY
• 金额: $ 13.93万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 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 2000-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6151075
• 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.

细菌紫红素可能是最简单的生物能传感器。 它使用小26kD蛋白吸收的轻能将运输 整个细胞膜的质子。 取得了很大的进步 在追踪质子穿过细胞膜的途径时 - “发生什么”的问题接近解决，并且 我们提出了许多实验来阐明质子释放部分 这个过程。我们现在已经开始在下一个进展 问题水平 - 提出一些关于 质子转移过程和发色团的机制 异构化 - “事情如何发生”的问题。 我们是 准备利用我们实验室的重大发现，即 PK的两个质子群可以解释为什么质子从 质子化的Schiff基地的柜台离子可以导致释放 来自Ca的质子。距离初始质子20个埃斯特罗姆单元 转移。 我们还开发了确定的新方法 残基突变在BR中对质子转移的影响 过程 - 通过它们对质子PK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 细菌紫红素越来越重要，因为细菌紫红素 继续将自己确立为一个研究一些的经典系统 生物学的基本问题。