9HYU

Cryo-EM structure of the Chromera velia PSI supercomplex at 1.84 Angstrom resolution

これはPDB形式変換不可エントリーです。

9HYU の概要

• エントリーDOI: 10.2210/pdb9hyu/pdb
• EMDBエントリー: 52518
• 分子名称: Superoxide dismutase [Fe], Photosystem I protein (PsaM), Photosystem I protein (PsaR), ... (36 entities in total)
• 機能のキーワード: photosynthesis, photosystem i, psi-fcp complex, chrome velia, cryo-em.
• 由来する生物種: Chromera velia; 詳細
• タンパク質・核酸の鎖数: 19
• 化学式量合計: 826448.78

構造登録者

Yuan, X.,Qian, P.,Sobotka, R.,Naschberger, A. (登録日: 2025-01-10, 公開日: 2026-01-28, 最終更新日: 2026-03-18)

主引用文献

Yuan, X.,Lukes, M.,Qian, P.,Charras, Q.,Smrcka, T.,Man, P.,Kovarova, L.,Konik, P.,Heilmann, E.,Al-Amoudi, A.,Sobotka, R.,Naschberger, A.
The cryo-EM structure of Photosystem I from Chromera velia with a bound superoxide dismutase heterodimer.
Nat Commun, 17:913-913, 2025

PubMed Abstract: Photosystem I is a key component of the solar energy conversion machinery in oxygenic photosynthesis, and its core, where photochemistry occurs, is highly conserved. However, the coral-associated alga Chromera velia that is evolutionary linked to parasitic apicomplexans, exhibits Photosystem I with unusual features. These include the splitting of the central PsaA subunit and the binding of superoxide dismutases as regular subunits. The organization of such a unique Photosystem I was enigmatic. Here, we present the cryo-EM structure of Chromera velia Photosystem I at 1.84 Å resolution. Our work reveals a superoxide dismutase heterodimer bound to the stromal side of the core, stabilized by extensions of canonical subunits, a novel protein PsaV, and a reduced light-harvesting apparatus. We elucidate how the complex evolved to accommodate the superoxide dismutase, assemble the split PsaA, and integrate antenna proteins in a non-canonical orientation. Based on our data and prior physiological data, we propose that this specialized Photosystem I functions likely as an Mehler machine, redirecting electrons from Photosystem II back to water. This mechanism enables Chromera velia to manage redox imbalance and reduce photorespiration through localized oxygen consumption.

PubMed: 41423677
DOI: 10.1038/s41467-025-67637-0

実験手法

ELECTRON MICROSCOPY (1.84 Å)