期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 319, 期 2, 页码 501-515出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/S0022-2836(02)00168-7
关键词
bacterial photosynthesis; protein-protein interaction; electron transfer proteins; membrane proteins; protein complexes
资金
- NIGMS NIH HHS [GM-13191, GM-45162] Funding Source: Medline
In the photosynthetic bacterium Rhodobacter sphaeroides, a water soluble cytochrome c(2) (cyt c(2)) is the electron donor to the reaction center (RC), the membrane-bound pigment-protein complex that is the site of the primary light-induced electron transfer. To determine the interactions important for docking and electron transfer within the transiently bound complex of the two proteins, RC and cyt c(2) were co-crystallized in two monoclinic crystal forms. Cyt c(2) reduces the photo-oxidized RC donor (D+), a bacteriochlorophyll dimer, in the co-crystals in similar to0.9 mus, which is the same time as measured in solution. This provides strong evidence that the structure of the complex in the region of electron transfer is the same in the crystal and in solution. X-ray diffraction. data were collected from co-crystals to a maximum resolution of 2.40 Angstrom and refined to an R-factor of 22% (R-free = 26%). The structure shows the cyt c(2) to be positioned at the center of the periplasmic surface of the RC, with the heme edge located above the bacteriochlorophyll dimer. The distance between the closest atoms of the two cofactors is 8.4 Angstrom. The side-chain of Tyr L162 makes van der Waals contacts with both cofactors along the shortest intermolecular electron transfer pathway. The binding interface can be divided into two domains: (i) A short-range interaction domain that includes Tyr L162, and groups exhibiting non-polar interactions, hydrogen bonding, and a cation-pi interaction. This domain contributes to the strength and specificity of cyt c(2) binding. (ii) A long-range, electrostatic interaction domain that contains solvated complementary charges on the RC and cyt c(2). This domain, in addition to contributing to the binding, may help steer the unbound proteins toward the right conformation. (C) 2002 Elsevier Science Ltd. All rights reserved.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据