CRYSTALLOGRAPHIC REFINEMENT AT 2.3-ANGSTROM RESOLUTION AND REFINED MODEL OF THE PHOTOSYNTHETIC REACTION-CENTER FROM RHODOPSEUDOMONAS-VIRIDIS
CRYSTALLOGRAPHIC REFINEMENT AT 2.3-ANGSTROM RESOLUTION AND REFINED MODEL OF THE PHOTOSYNTHETIC REACTION-CENTER FROM RHODOPSEUDOMONAS-VIRIDIS
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DOI：
10.1006/jmbi.1994.0097
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发表时间：
1995-02-24
影响因子：
5.6
通讯作者：
MICHEL, H
中科院分区：
文献类型：
--
作者：
DEISENHOFER, J;EPP, O;MICHEL, H
紫色细菌红假单胞菌（Rhodopseudomonas viridis）光合反应中心的原子模型在2.3埃分辨率下被精确到x值为0.193。精炼后的模型包含10288个非氢原子；其中10045个有明确的电子密度。鲁扎蒂图显示平均坐标误差为0.26埃。在精化过程中，发现了一个部分有序的类胡萝卜素、一个在部分占据的Q(B)位点的一元醌、一个洗涤剂分子、7个假定的硫酸盐离子和201个水分子的位置。超过一半的这些水在蛋白质亚基之间的界面结合，因此对亚基相互作用有重要贡献。水分子在一些辅助因子的环境中也起着重要的结构和可能的功能作用。两个水分子与辅助的细菌叶绿素和靠近一对特殊的细菌叶绿素的蛋白质形成氢键，细菌叶绿素是主要的电子供体。在仲醌Q(B)的结合位点附近结合了一组约10个水分子，这些水分子可能参与了质子向双还原Q(B)的转移。
The atomic model of the photosynthetic reaction centre from the purple bacterium Rhodopseudomonas viridis has been refined to an X-value of 0.193 at 2.3 Angstrom resolution. The refined model contains 10,288 non-hydrogen atoms; 10,045 of these have well defined electron density. A Luzzati-plot indicates an average co-ordinate error of 0.26 Angstrom. During refinement, the positions of a partially ordered carotenoid, a unibiquinone in the partially occupied Q(B) site, a detergent molecule, seven putative sulphate ions, and 201 water molecules were found. More than half of these waters are bound at interfaces between protein subunits and therefore contribute significantly to subunit interactions. Water molecules also play important structural and probably functional roles in the environment of some of the cofactors. Two water molecules form hydrogen bonds to the accessory bacteriochlorophylls and to the protein in the vicinity of the special pair of bacteriophylls, the primary electron donor. A group of about 10 water molecules is bound near the binding site of the secondary quinone Q(B) These waters are likely to participate in the transfer of protons to the doubly reduced Q(B).