Mechanism of proton transport in bacteriorhodopsin from crystallographic structures of the K, L, M1, M2, and M2′ intermediates of the photocycle
Mechanism of proton transport in bacteriorhodopsin from crystallographic structures of the K, L, M1, M2, and M2′ intermediates of the photocycle
复制标题
DOI：
10.1016/s0022-2836(03)00263-8
复制
发表时间：
2003-04-25
影响因子：
5.6
通讯作者：
Schobert, B
中科院分区：
文献类型：
--
作者：
Lanyi, JK;Schobert, B
我们在 170 K 的光稳态下，在 60% 占用率的红色激光照射下，在细菌视紫红质晶体中产生了光循环的 L 中间体，并以 1.62 埃的分辨率确定了其结构。通过该模型，可以获得初始细菌视紫红质以及运输周期中前五个状态的高分辨率结构信息。这些状态涉及视网膜的光异构化及其初始构型变化、视网膜希夫碱的去质子化和质子向细胞外膜表面的耦合释放，以及允许希夫碱从细胞质侧重新质子化的开关事件。六个结构模型以原子细节描述了视网膜的转变及其与水 402、Asp85 和 Asp212 的相互作用，以及远离席夫碱的功能残基的位移。这些变化为扭曲的视网膜松弛如何引起水和蛋白质原子的运动提供了理论依据，从而导致矢量质子在希夫碱之间的转移。 (C) 2003 Elsevier Science Ltd. 保留所有权利。
We produced the L intermediate of the photocycle in a bacteriorhodopsin crystal in photo-stationary state at 170 K with red laser illumination at 60% occupancy, and determined its structure to 1.62 Angstrom resolution. With this model, high-resolution structural information is available for the initial bacteriorhodopsin, as well as the first five states in the transport cycle. These states involve photo-isomerization of the retinal and its initial configurational changes, deprotonation of the retinal Schiff base and the coupled release of a proton to the extracellular membrane surface, and the switch event that allows reprotonation of the Schiff base from the cytoplasmic side. The six structural models describe the transformations of the retinal and its interaction with water 402, Asp85, and Asp212 in atomic detail, as well as the displacements of functional residues farther from the Schiff base. The changes provide rationales for how relaxation of the distorted retinal causes movements of water and protein atoms that result in vectorial proton transfers to and from the Schiff base. (C) 2003 Elsevier Science Ltd. All rights reserved.