MECHANISM OF CHLORIDE TRANSPORT BY HALORHODOPSIN

盐视紫红质的氯离子转运机制

• 批准号: 3277142
• 负责人: JANOS K LANYI
• 金额: $ 10.22万
• 依托单位: UNIVERSITY OF CALIFORNIA-IRVINE
• 依托单位国家: 美国
• 财政年份: 1981
• 资助国家: 美国
• 起止时间: 1981-07-01 至 1987-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3277142
• 关键词: Halobacteriaceae; bacteriorhodopsins; chemical structure function; crosslink; gel electrophoresis; liposomes; membrane activity; microorganism culture; mutant; photobiology; photochemistry; spectrometry; Halobacteriaceae; bacteriorhodopsins; chemical structure function; crosslink; gel electrophoresis; liposomes; membrane activity; microorganism culture; mutant; photobiology; photochemistry; spectrometry

We will explore the mechanism by which halorhodopsin functions as a light-driven electrogenic chloride pump. This chloride-transport system, found in the cytoplasmic membrane of halobacteria, is a retinal pigment whose chromophore exhibits flash-induced absorbance changes dependent on the presence of chloride. Furthermore, chloride, as well as other anions, apparently influences the pK of the retinal Schiff's base. Studying these phenomena in more detail, and using specific labels to modify selected amino acid residues, we will describe the groups involved in the binding of chloride, the number of chloride-binding sites and their relationship to one another, and the role of protonation/deprotonation of groups in the chloride translocation. Special attention will be paid to the possibility that halorhodopsin contains a sulfhydryl group with an influence on the photochemistry of the pigment. Although the purified chromoprotein (apparent molecular weight 21 kDa) of halorhodopsin binds chloride, and shows the chloride-dependent effects observed with the intact system, we will search for and identify any other, so far unknown, components of halorhodopsin. In this study we expect to establish the basis for a first model of the molecular mechanism of how the photochemical changes are related to chloride translocation against an electrochemical gradient. Such a model should contribute to the understanding of ionic pumps in general.

我们将探索甲氟淡鱼充当的机制 光驱动的电氯泵。 这个氯化物传输系统， 在卤细菌的细胞质膜中发现的是视网膜色素 其发色团表现出闪光引起的吸光度变化 氯化物的存在。 此外，氯化物以及其他阴离子， 显然会影响视网膜基地的PK。 研究这些 现象更详细，并使用特定标签修改选定 氨基酸残基，我们将描述涉及结合的组 氯化物，氯化物结合位点的数量及其与之的关系 彼此，以及组中质子化/去质子化的作用 氯化物易位。 特别关注可能性 那甲称二紫红质含有一组对 色素的光化学。 虽然纯化的铬蛋白 （明显的分子量21 kDa）卤代紫红蛋白结合氯化物，并结合 显示了与完整系统观察到的氯化物依赖性效应，我们 将搜索并确定到目前为止的其他任何其他组件 Halorhopopsin。 在这项研究中，我们期望为第一个建立基础 光化学变化的分子机制模型 与电化学梯度相关的氯化物易位。 这样的模型应有助于理解离子泵 一般的。