9LTV

Cryo-EM structure of the Dinoroseobacter shibae RC-LH1 supercomplex with incomplete LH1 ring(State 2)

9LTV の概要

• エントリーDOI: 10.2210/pdb9ltv/pdb
• EMDBエントリー: 63382
• 分子名称: Antenna pigment protein beta chain, PROTOPORPHYRIN IX CONTAINING FE, UBIQUINONE-10, ... (13 entities in total)
• 機能のキーワード: reaction centre light-harvesting 1, photosynthesis
• 由来する生物種: Dinoroseobacter shibae DFL 12 = DSM 16493; 詳細
• タンパク質・核酸の鎖数: 33
• 化学式量合計: 350662.08

構造登録者

Liu, Z.K.,Wang, P.,Liu, L.N. (登録日: 2025-02-06, 公開日: 2025-10-01, 最終更新日: 2026-04-15)

主引用文献

Liu, Z.K.,Li, J.X.,Zhang, Y.Y.,Lv, J.L.,Li, K.,Chen, X.L.,Zhang, Y.Z.,Liu, L.N.,Wang, P.
Structural basis for aerobic anoxygenic photosynthesis in the reaction center-light-harvesting 1 (RC-LH1) supercomplex of Dinoroseobacter shibae.
Commun Biol, 8:1565-1565, 2025

PubMed Abstract: Aerobic anoxygenic phototrophic (AAP) bacteria are essential for oceanic carbon cycling. However, their architecture and structural adaptations of their photosynthetic systems to ensure adequate light harvesting, electron transport, and oxidative resilience in oxygen-rich environments remain poorly understood. In this study, we present a 2.4-Å cryo-EM structure of the reaction center-light-harvesting 1 (RC-LH1) supercomplex from Dinoroseobacter shibae DFL-12, a marine AAP bacterial symbiont of benthic dinoflagellates. This RC-LH1 supercomplex features a closed LH1 ring comprising 17 αβ-subunits, each containing two spheroidenones per αβ-heterodimer-a previously unreported configuration in phototrophic bacteria. The cytochrome subunit of the RC is truncated to three hemes, in contrast to the four-heme configuration found in anaerobic relatives. The structure also reveals elongated bacteriochlorophyll (BChl) spacing, which may account for its blue-shifted absorption maximum that is optimized for low-light benthic environments. Furthermore, we identify a previously unknown subunit, protein-LRC, which is hypothesized to functionally couple photochemical and respiratory electron transport. Collectively, these specific structural features allow AAP bacteria to balance anoxygenic photosynthesis and protection against oxidative damage, providing a mechanistic framework for them to thrive in oxygenated marine environments. Our study provides insights into the structural and functional variability of bacterial photosynthesis in response to oxygenated marine environments.

PubMed: 41238682
DOI: 10.1038/s42003-025-08935-7

実験手法

ELECTRON MICROSCOPY (2.75 Å)