Chang C H, Tiede D, Tang J, Smith U, Norris J, Schiffer M
FEBS Lett. 1986 Sep 1;205(1):82-6. doi: 10.1016/0014-5793(86)80870-5.
The molecular replacement method has been successfully used to provide a structure for the photosynthetic reaction center of Rhodopseudomonas sphaeroides at 3.7 A resolution. Atomic coordinates derived from the R. viridis reaction center were used in the search structure. The crystallographic R-factor is 0.39 for reflections between 8 and 3.7 A. Validity of the resulting model is further suggested by the visualization of amino acid side chains not included in the R. viridis search structure, and by the arrangements of the reaction centers in the unit cell. In the initial calculations quinones or pigments were not included; nevertheless, in the resulting electron density map, electron density for both quinones QA and QB appears along with the bacteriochlorophylls and bacteriopheophytins. Kinetic analysis of the charge recombination shows that the secondary quinone is fully functional in the R. sphaeroides crystal.
分子置换法已成功用于以3.7埃分辨率提供球形红假单胞菌光合反应中心的结构。来自绿硫红假单胞菌反应中心的原子坐标被用于搜索结构。对于8至3.7埃之间的反射，晶体学R因子为0.39。绿硫红假单胞菌搜索结构中未包含的氨基酸侧链的可视化以及晶胞中反应中心的排列进一步表明了所得模型的有效性。在初始计算中未包含醌或色素；然而，在所得的电子密度图中，醌QA和QB的电子密度与细菌叶绿素和细菌脱镁叶绿素一起出现。电荷复合的动力学分析表明，次级醌在球形红假单胞菌晶体中具有完全功能。
