Structural Studies of Photosynthetic Membrane Proteins

描述（由申请人提供）紫色光合细菌的光收集天线系统的效率大于90%，是显着的。充分理解这种效率的先决条件是详细了解天线系统的主要组成部分，LH1， LH2和反应中心（RC），它们都是膜蛋白。LH1的结构仅以4.8A的分辨率已知，并且比LH2和RC单独的结构特征更差。本提案概述了利用魔角旋转（MAS）条件下的固态核磁共振（SS NMR），结合二维和三维核磁共振实验和蛋白质样品的选择性同位素标记，获得LH1体系和相关LH1- rc配合物的中等至高分辨率结构细节的计划。该方法采用SS核磁共振获得LH1体系所有组分氨基酸残基的序列特异性配位，使用这些配位和额外的核磁共振实验来确定结构约束。这项拟议的研究将为膜蛋白的研究提供有关光合作用的信息，并进一步测试SS NMR方法，膜蛋白是生物化学研究的一个关键领域，在医学领域具有重要应用。

DESCRIPTION (provided by applicant) The efficiency of the light harvesting antenna system in purple photosynthetic bacteria, at greater than 90%, is remarkable. A prerequisite to full understanding of this efficiency is a detailed structural knowledge of the major components of the antenna system, LH1, LH2, and the Reaction Center (RC), which are all membrane proteins. The structure of LH1 is only known to a resolution of 4.8A, and is less-well characterized than LH2 and the RC alone. This proposal outlines plans to obtain moderate to high-resolution structural detail of the LH1 system and the related LH1-RC complex, by utilizing Solid State Nuclear Magnetic Resonance (SS NMR) under conditions of Magic Angle Spinning (MAS) in conjunction with two- and three-dimensional NMR experiments and selective isotopic labeling of protein samples. The methodology employs SS NMR to obtain sequence-specific assignments of the amino acid residues of all constituents of the LH1 system, using these assignments and additional NMR experiments to determine structural constraints. The proposed study will provide information about photosynthesis and a further test of SS NMR methods to the study of membrane proteins - a crucial area of biochemical research with significant applications in the medical field.