Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.
J Photochem Photobiol B. 2011 Jul-Aug;104(1-2):158-64. doi: 10.1016/j.jphotobiol.2011.02.006. Epub 2011 Mar 4.
The PsbP and PsbQ proteins are extrinsic subunits of the photosystem II (PSII) supercomplex, which are found in green plants including higher plants and green algae. These proteins are thought to have evolved from their cyanobacterial homologs; cyanoP and cyanoQ respectively. It has been suggested that the functions of PsbP and PsbQ have largely changed from those of cyanoP and cyanoQ. In addition, multiple isoforms and homologs of PsbP and PsbQ were found in green plants, indicating that the acquisition of PsbP and PsbQ in PSII is not a direct path but a result of intensive functional divergence during evolution from cyanobacterial endosymbiont to chloroplast. In this review, we highlight newly introduced topics related to the functions and structures of both PsbP and PsbQ proteins. The present data suggest that PsbP together with PsbQ have specific and important roles in coordinating the activity of the donor and acceptor sides of PSII and stabilizing the active form of the PSII-light-harvesting complex II (LHCII) supercomplex.
PsbP 和 PsbQ 蛋白是光合系统 II（PSII）超复合体的外在亚基，存在于包括高等植物和绿藻在内的绿色植物中。这些蛋白被认为是从它们的蓝细菌同源物，即 cyanoP 和 cyanoQ 进化而来的。有人提出，PsbP 和 PsbQ 的功能已经从 cyanoP 和 cyanoQ 的功能发生了很大的变化。此外，在绿色植物中发现了 PsbP 和 PsbQ 的多种同工型和同源物，这表明 PSII 中 PsbP 和 PsbQ 的获得不是直接途径，而是从蓝细菌内共生体到叶绿体的进化过程中强烈的功能分化的结果。在这篇综述中，我们强调了与 PsbP 和 PsbQ 蛋白的功能和结构相关的新引入的课题。目前的数据表明，PsbP 与 PsbQ 一起在协调 PSII 的供体和受体侧的活性以及稳定 PSII-光捕获复合物 II（LHCII）超复合体的活性形式方面具有特定和重要的作用。
