Graduate School of Human and Environmental Studies, Kyoto University, Kyoto, Japan.
Photochem Photobiol. 2010 Jan-Feb;86(1):62-9. doi: 10.1111/j.1751-1097.2009.00619.x. Epub 2009 Sep 21.
We compared the optical properties of the trimeric photosystem (PS) I complexes of the primordial cyanobacterium Gloeobacter violaceus PCC 7421 with those of Synechocystis sp. PCC 6803. Gloeobacter violaceus PS I showed (1) a shorter difference maximum of P700 by approximately 2 nm, (2) a smaller antenna size by approximately 10 chlorophyll (Chl) a molecules and (3) an absence of Red Chls. The energy transfer kinetics in the antennae at physiological temperatures were very similar between the two species due to the thermal equilibrium within the antenna; however, they differed at 77 K where energy transfer to Red Chls was clearly observed in Synechocystis sp. PCC 6803. Taken together with the lower P700 redox potential in G. violaceus by approximately 60 mV, we discuss differences in the optical properties of the PS I complexes with respect to the amino acid sequences of core proteins and further to evolution of cyanobacteria.
我们比较了原始蓝细菌 Gloeobacter violaceus PCC 7421 的三聚体光系统 I（PS I）复合物与 Synechocystis sp. PCC 6803 的光学性质。Gloeobacter violaceus PS I 表现出：（1）P700 的差异最大值短约 2nm；（2）天线尺寸小约 10 个叶绿素（Chl）a 分子；（3）不存在红叶绿素。由于天线内的热平衡，两种物种在生理温度下天线中的能量转移动力学非常相似；然而，在 77 K 时，在 Synechocystis sp. PCC 6803 中明显观察到能量向红叶绿素的转移。再加上 G. violaceus 中 P700 氧化还原电位低约 60 mV，我们讨论了 PS I 复合物的光学性质与核心蛋白的氨基酸序列以及蓝细菌的进化有关的差异。
