7Y8A

Cryo-EM structure of cryptophyte photosystem I

7Y8A の概要

• エントリーDOI: 10.2210/pdb7y8a/pdb
• EMDBエントリー: 33683
• 分子名称: ACPI-1, Photosystem I P700 chlorophyll a apoprotein A1, Photosystem I P700 chlorophyll a apoprotein A2, ... (39 entities in total)
• 機能のキーワード: cryptophyte, photosystem i, evolution, photosynthesis
• 由来する生物種: Chroomonas placoidea; 詳細
• タンパク質・核酸の鎖数: 26
• 化学式量合計: 863763.55

構造登録者

Zhao, L.S.,Zhang, Y.Z.,Liu, L.N.,Li, K. (登録日: 2022-06-23, 公開日: 2023-04-12, 最終更新日: 2024-11-13)

主引用文献

Zhao, L.S.,Wang, P.,Li, K.,Zhang, Q.B.,He, F.Y.,Li, C.Y.,Su, H.N.,Chen, X.L.,Liu, L.N.,Zhang, Y.Z.
Structural basis and evolution of the photosystem I-light-harvesting supercomplex of cryptophyte algae.
Plant Cell, 35:2449-2463, 2023

PubMed Abstract: Cryptophyte plastids originated from a red algal ancestor through secondary endosymbiosis. Cryptophyte photosystem I (PSI) associates with transmembrane alloxanthin-chlorophyll a/c proteins (ACPIs) as light-harvesting complexes (LHCs). Here, we report the structure of the photosynthetic PSI-ACPI supercomplex from the cryptophyte Chroomonas placoidea at 2.7-Å resolution obtained by crygenic electron microscopy. Cryptophyte PSI-ACPI represents a unique PSI-LHCI intermediate in the evolution from red algal to diatom PSI-LHCI. The PSI-ACPI supercomplex is composed of a monomeric PSI core containing 14 subunits, 12 of which originated in red algae, 1 diatom PsaR homolog, and an additional peptide. The PSI core is surrounded by 14 ACPI subunits that form 2 antenna layers: an inner layer with 11 ACPIs surrounding the PSI core and an outer layer containing 3 ACPIs. A pigment-binding subunit that is not present in any other previously characterized PSI-LHCI complexes, ACPI-S, mediates the association and energy transfer between the outer and inner ACPIs. The extensive pigment network of PSI-ACPI ensures efficient light harvesting, energy transfer, and dissipation. Overall, the PSI-LHCI structure identified in this study provides a framework for delineating the mechanisms of energy transfer in cryptophyte PSI-LHCI and for understanding the evolution of photosynthesis in the red lineage, which occurred via secondary endosymbiosis.

PubMed: 36943796
DOI: 10.1093/plcell/koad087

実験手法

ELECTRON MICROSCOPY (2.71 Å)