Ifuku Kentaro, Sato Fumihiko
Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto, 606-8502 Japan.
Plant Cell Physiol. 2002 Oct;43(10):1244-9. doi: 10.1093/pcp/pcf136.
One function of the extrinsic 23-kDa protein in photosystem II (OEC23) is to retain Ca(2+ )and Cl(-), two essential cofactors for photosynthetic oxygen evolution. A truncated mutant of OEC23 (OEC23 Delta19) revealed that 19 residues of the N-terminus of OEC23 were necessary for Ca(2+ )retention but not for its proper interaction with OEC17, the extrinsic 17-kDa protein in photosystem II. The lost ability of OEC23 Delta19 to reconstitute the oxygen-evolving activity was partially restored by OEC17 binding, suggesting the involvement of OEC17 in Ca(2+ )retention in photosystem II.
光系统II中23千道尔顿外在蛋白（OEC23）的一个功能是保留Ca(2+)和Cl(-)，这是光合放氧的两个必需辅助因子。OEC23的一个截短突变体（OEC23 Delta19）表明，OEC23 N端的19个残基对于保留Ca(2+)是必需的，但对于其与光系统II中17千道尔顿外在蛋白OEC17的正确相互作用并非必需。OEC17结合部分恢复了OEC23 Delta19重建放氧活性的丧失能力，这表明OEC17参与了光系统II中Ca(2+)的保留。
