7SA3

Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light

7SA3 の概要

• エントリーDOI: 10.2210/pdb7sa3/pdb
• EMDBエントリー: 24943
• 分子名称: Photosystem q(B) protein, CALCIUM ION, CHLORIDE ION, ... (24 entities in total)
• 機能のキーワード: photosystem ii, far-red light photoacclimation, chlorophyll f, chlorophyll d, bicarbonate, photoactivation, photosynthesis, cyanobacteria
• 由来する生物種: Synechococcus sp. PCC 7335; 詳細
• タンパク質・核酸の鎖数: 9
• 化学式量合計: 256677.94

構造登録者

Gisriel, C.J.,Bryant, D.A.,Brudvig, G.W. (登録日: 2021-09-22, 公開日: 2021-12-01, 最終更新日: 2024-06-05)

主引用文献

Gisriel, C.J.,Shen, G.,Ho, M.Y.,Kurashov, V.,Flesher, D.A.,Wang, J.,Armstrong, W.H.,Golbeck, J.H.,Gunner, M.R.,Vinyard, D.J.,Debus, R.J.,Brudvig, G.W.,Bryant, D.A.
Structure of a monomeric photosystem II core complex from a cyanobacterium acclimated to far-red light reveals the functions of chlorophylls d and f.
J.Biol.Chem., 298:101424-101424, 2021

PubMed Abstract: Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700-800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the "red limit" for light required to drive photochemical catalysis of water oxidation. Changes to the architecture of FRL-PSII were previously unknown, and the positions of Chl d and Chl f molecules had only been proposed from indirect evidence. Here, we describe the 2.25 Å resolution cryo-EM structure of a monomeric FRL-PSII core complex from Synechococcus sp. PCC 7335 cells that were acclimated to FRL. We identify one Chl d molecule in the Chl position of the electron transfer chain and four Chl f molecules in the core antenna. We also make observations that enhance our understanding of PSII biogenesis, especially on the acceptor side of the complex where a bicarbonate molecule is replaced by a glutamate side chain in the absence of the assembly factor Psb28. In conclusion, these results provide a structural basis for the lower energy limit required to drive water oxidation, which is the gateway for most solar energy utilization on earth.

PubMed: 34801554
DOI: 10.1016/j.jbc.2021.101424

実験手法

ELECTRON MICROSCOPY (2.25 Å)