Allen J P, Feher G, Yeates T O, Komiya H, Rees D C
University of California, San Diego, La Jolla 92093.
Proc Natl Acad Sci U S A. 1988 Nov;85(22):8487-91. doi: 10.1073/pnas.85.22.8487.
The three-dimensional structure of the reaction center (RC) from Rhodobacter sphaeroides has been determined by x-ray diffraction to a resolution of 2.8 A with an R value of 24%. The interactions of the protein with the primary quinone, QA, secondary quinone, QB, and the nonheme iron are described and compared to those of RCs from Rhodopseudomonas viridis. Structural differences between the QA and QB environments that contribute to the function of the quinones (the electron transfer from QA- to QB and the charge recombination of QA-, QB- with the primary donor) are delineated. The protein residues that may be involved in the protonation of QB are identified. A pathway for the doubly reduced QB to dissociate from the RC is proposed. The interactions between QB and the residues that have been changed in herbicide-resistant mutants are described. The environment of the nonheme iron is compared to the environments of metal ions in other proteins.
球形红杆菌反应中心（RC）的三维结构已通过X射线衍射确定，分辨率为2.8埃，R值为24%。描述了该蛋白质与初级醌QA、次级醌QB以及非血红素铁的相互作用，并与绿假单胞菌反应中心的相互作用进行了比较。阐述了QA和QB环境之间的结构差异，这些差异有助于醌的功能（从QA-到QB的电子转移以及QA-、QB-与初级供体的电荷复合）。确定了可能参与QB质子化的蛋白质残基。提出了双还原态QB从反应中心解离的途径。描述了QB与抗除草剂突变体中发生变化的残基之间的相互作用。将非血红素铁的环境与其他蛋白质中金属离子的环境进行了比较。
