8GN2

Crystal structure of PPBQ-bound photosystem II complex

8GN2 の概要

• エントリーDOI: 10.2210/pdb8gn2/pdb
• 分子名称: Photosystem II protein D1, Photosystem II reaction center protein K, Photosystem II reaction center protein L, ... (44 entities in total)
• 機能のキーワード: photosystem, electron transfer, electron acceptor, quinone, photosynthesis
• 由来する生物種: Thermostichus vulcanus; 詳細
• タンパク質・核酸の鎖数: 39
• 化学式量合計: 748841.77

構造登録者

Kamada, S.,Nakajima, Y.,Shen, J.-R. (登録日: 2022-08-22, 公開日: 2023-07-05, 最終更新日: 2025-07-30)

主引用文献

Kamada, S.,Nakajima, Y.,Shen, J.R.
Structural insights into the action mechanisms of artificial electron acceptors in photosystem II.
J.Biol.Chem., 299:104839-104839, 2023

PubMed Abstract: Photosystem II (PSII) utilizes light energy to split water, and the electrons extracted from water are transferred to Q, a plastoquinone molecule bound to the D1 subunit of PSII. Many artificial electron acceptors (AEAs) with molecular structures similar to that of plastoquinone can accept electrons from PSII. However, the molecular mechanism by which AEAs act on PSII is unclear. Here, we solved the crystal structure of PSII treated with three different AEAs, 2,5-dibromo-1,4-benzoquinone, 2,6-dichloro-1,4-benzoquinone, and 2-phenyl-1,4-benzoquinone, at 1.95 to 2.10 Å resolution. Our results show that all AEAs substitute for Q and are bound to the Q-binding site (Q site) to receive electrons, but their binding strengths are different, resulting in differences in their efficiencies to accept electrons. The acceptor 2-phenyl-1,4-benzoquinone binds most weakly to the Q site and showed the highest oxygen-evolving activity, implying a reverse relationship between the binding strength and oxygen-evolving activity. In addition, a novel quinone-binding site, designated the Q site, was discovered, which is located in the vicinity of Q site and close to Q site, a binding site reported previously. This Q site is expected to play a role as a channel or a storage site for quinones to be transported to the Q site. These results provide the structural basis for elucidating the actions of AEAs and exchange mechanism of Q in PSII and also provide information for the design of more efficient electron acceptors.

PubMed: 37209822
DOI: 10.1016/j.jbc.2023.104839

実験手法

X-RAY DIFFRACTION (1.95 Å)