TRANSLOCATION IN ENERGY CONVERSION--STRUCTURAL STUDIES

该项目的总体目标是确定 分子内和分子间结构在生物能源中的作用 转换。这里提出的结构研究涉及到 圆柱面平均轮廓结构的确定 特定双分子络合物中的膜分子组成 参与中等分辨率的能量转换(约10 埃)；这些组件之间的空间关系，相对 彼此之间以及膜的整体轮廓结构之间的关系； 与这些相关的氧化还原中心之间的空间关系 组件，在这些复合体中彼此相对，并且相对于 膜的整体轮廓结构，精度为+/-L-2 埃斯特罗姆。通过将这些结构参数与 这些组件和/或其复合体展示的能力 有效的电子传递和跨膜的产生 电化学势(并最终合成三磷酸腺苷) 重组的、面向矢量的单膜系统，我们希望 对能量耦合的机制有了实质性的了解 生物膜。非共振和共振X射线技术 衍射法、中子衍射法、EXAFS(扩展X射线吸收精细法 结构)和偏振EXAFS光谱与光学线性二色性 将被用来研究相关的膜蛋白，包括 光合作用反应中心、细胞色素氧化酶、细胞色素c和 细胞色素b/c1及其形式的各种双分子络合物 面向矢量的单膜系统。他们的反应 中心-细胞色素b/c1-细胞色素c络合物表现出高效的 光驱动的一系列循环电子转移反应。

The overall goal of this project is to determine important aspects of the role of intramolecular and intermolecular structure in biological energy conversion. The structural studies proposed here concern the determination of the cylindrically-averaged profile structures of the membrane molecular components within specific bimolecular complexes involved in energy conversion at moderate resolution (approximately 10 angstroms); the spatial relationships between these components, relative to each other and to the overall profile structure of the membrane; and the spatial relationships among the redox centers associated with these components, relative to each other within these complexes and relative to the overall profile structure of the membrane, with an accuracy of +/-l-2 Angstroms. Through a correlation of such structural parameters with the capabilities of these components and/or complexes thereof to exhibit efficient electron transport and the generation of transmembrane electrochemical potentials (and ultimately the synthesis of ATP) in reconstituted,vectorially oriented single membrane systems, we hope to gain substantial insight into the mechanism of energy coupling in biological membranes. The techniques of nonresonance and resonance x-ray diffraction, neutron diffraction, EXAFS (Extended X-ray Absorption Fine Structure) and polarized EXAFS spectroscopy and optical linear dichroism will be utilized to study the relevant membrane proteins, including photosynthetic reaction centers, cytochrome oxidase, cytochrome c and cytochrome b/c1 and various bimolecular complexes thereof in the form of vectorially oriented, single membrane systems. The reaction center-cytochrome b/c1-cytochrome c complexes exhibit an efficient light-driven cyclic series of electron transfer reactions.