Pathways of electron and proton flow in a transmembrane, photon-driven quinone reductase/translocase supercomplex of proteins

这项拟议的研究旨在细胞过程的组件之间的相互作用，在细胞质膜片段和原子之间的规模中间，包括个别蛋白质成分的膜结合催化剂。我们正在研究跨膜蛋白复合物内部和之间相互作用结构域的结构和功能，重点是我们称之为RC/LH 1/PufX超复合物。这种光合色素-蛋白质超复合物由反应中心（RC）复合物、捕光1（LH 1）复合物和PufX蛋白质关键组分组成。主要目标是阐明RC/LH 1/PufX超复合物中的电子和质子流的途径，该超复合物在模式生物细菌Rhodobacter sphaeroides中充当光子（光）驱动的醌还原酶/转位酶。其他目标是确定超复合物如何组装和易位醌，以及RC特异性辅因子细菌脱镁叶绿素的生物起源。我们还希望解决RC/LH 1/PufX超复合物的高分辨率晶体结构，以提供对PufX蛋白的位置和功能的3-D见解，并促进定点诱变实验的设计和解释，以测试由结构数据产生的功能假设。这项研究对于推进蛋白质催化电化学反应催化的基础知识非常重要，特别是在使用生物材料发电的应用方面。因此，这项研究不仅对科学家感兴趣，而且对可以从收集太阳能的应用中受益的公众也感兴趣。预计这项研究将促进膜蛋白超复合物的组装和相互作用的理解，并为基于生物系统的光伏器件的工程提供基础。改进的光伏设备将使加拿大受益，因为它允许更多地使用一种清洁的、基本上无限的能源。

This proposed research is aimed at interactions between components of cellular processes, on a scale intermediate between cytoplasmic membrane fragments and the atoms comprising individual protein components of membrane-bound catalysts. We are studying the structure and function of domains of interaction within and between transmembrane protein complexes, with a focus on what we call the RC/LH1/PufX supercomplex. This photosynthetic pigment-protein supercomplex is composed of the reaction center (RC) complex, the light-harvesting 1 (LH1) complex, and the PufX protein key component. The primary goal is to elucidate pathways of electron and proton flow in the RC/LH1/PufX supercomplex, which functions as a photon- (light-) driven quinone reductase/translocase in a model organism, the bacterium Rhodobacter sphaeroides. Other goals are to determine how the supercomplex assembles and translocates quinones, and the biogenesis of the RC-specific cofactor, bacteriopheophytin. We also wish to solve a high-resolution crystal structure of an RC/LH1/PufX supercomplex to provide 3-D insights into the location and function of the PufX protein, and to facilitate the design and interpretation of site-directed mutagenesis experiments to test functional hypotheses arising from the structural data. This research is important to advance fundamental knowledge of the catalysis of protein-catalyzed electrochemical reactions, especially in relation to applications using biological material to generate electricity. Thus this research is of interest not only to scientists, but also the general public who could benefit from applications to harvest solar energy. It is anticipated that this research will advance the understanding of the assembly and interaction of membrane protein supercomplexes in general, with the additional potential of providing a foundation for the engineering of photovoltaic devices based on biological systems. Improved photovoltaic devices would benefit Canada by allowing increased use of a clean, essentially limitless energy source.