Kühn Philipp, Pieper Jörg, Kaminskaya Olga, Eckert Hann-Jörg, Lechner Ruep E, Shuvalov Vladimir, Renger Gernot
Max-Volmer-Laboratorium für Biophysikalische Chemie, Technische Universität Berlin, Strasse des 17. Juni 135, 10623 Berlin, Germany.
Photosynth Res. 2005 Jun;84(1-3):317-23. doi: 10.1007/s11120-004-7079-8.
This short communication addresses three topics of photosynthetic water cleavage in Photosystem II (PS II): (a) effect of protonation in the acidic range on the extent of the 'fast' ns kinetics of P680+. reduction by YZ, (b) mechanism of O-O bond formation and (c) role of protein flexibility in the functional integrity of PS II. Based on measurements of light-induced absorption changes and quasielastic neutron scattering in combination with mechanistic considerations, evidence is presented for the protein acting as a functionally active constituent of the water cleavage machinery, in particular, for directed local proton transfer. A specific flexibility emerging above a threshold of about 230 K is an indispensable prerequisite for oxygen evolution and plastoquinol formation.
本简短通讯探讨了光系统II（PS II）中光合水裂解的三个主题：（a）酸性范围内质子化对P680 +被YZ还原的“快速”纳秒动力学程度的影响，（b）O - O键形成机制，以及（c）蛋白质灵活性在PS II功能完整性中的作用。基于光诱导吸收变化和准弹性中子散射的测量，并结合机理考虑，有证据表明蛋白质作为水裂解机制的功能活性成分，特别是对于定向局部质子转移。在约230 K的阈值以上出现的特定灵活性是氧气释放和质体醌形成的不可或缺的先决条件。
