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

Pu Qian, Tristan I. Croll, David J. K. Swainsbury, Pablo Castro-Hartmann, Nigel W. Moriarty, Kasim Sader, C. Neil Hunter

Research output: Contribution to journalArticlepeer-review

21 Citations (Scopus)
10 Downloads (Pure)


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.

Original languageEnglish
Pages (from-to)3253-3263
Number of pages11
JournalBiochemical Journal
Issue number17
Early online date17 Aug 2021
Publication statusPublished - 7 Sep 2021

Cite this