Repository logo
 

Cryo-EM structure of the Rhodospirillum rubrum RC-LH1 complex at 2.5 Å.

Published version
Peer-reviewed

Type

Article

Change log

Authors

Qian, Pu 
Croll, Tristan I 
Swainsbury, David JK 
Castro-Hartmann, Pablo 
Moriarty, Nigel W 

Abstract

The reaction centre light-harvesting 1 (RC-LH1) complex is the core functional component of bacterial photosynthesis. We determined the cryo-electron microscopy (cryo-EM) structure of the RC-LH1 complex from Rhodospirillum rubrum at 2.5 Å resolution, which reveals a unique monomeric bacteriochlorophyll with a phospholipid ligand in the gap between the RC and LH1 complexes. The LH1 complex comprises a circular array of 16 αβ-polypeptide subunits that completely surrounds the RC, with a preferential binding site for a quinone, designated QP, on the inner face of the encircling LH1 complex. Quinols, initially generated at the RC QB site, are proposed to transiently occupy the QP site prior to traversing the LH1 barrier and diffusing to the cytochrome bc1 complex. Thus, the QP site, which is analogous to other such sites in recent cryo-EM structures of RC-LH1 complexes, likely reflects a general mechanism for exporting quinols from the RC-LH1 complex.

Description

Keywords

carotenoids, cryo-electron microscopy, light-harvesting, photosynthesis, quinone, reaction centre, Bacterial Proteins, Bacteriochlorophylls, Benzoquinones, Binding Sites, Cryoelectron Microscopy, Crystallization, Electron Transport Complex III, Hydrogen Bonding, Hydroquinones, Ligands, Light-Harvesting Protein Complexes, Phospholipids, Protein Conformation, alpha-Helical, Rhodospirillum rubrum

Journal Title

Biochem J

Conference Name

Journal ISSN

0264-6021
1470-8728

Volume Title

478

Publisher

Portland Press Ltd.
Sponsorship
Wellcome Trust (209407/Z/17/Z)