Download MendeleyCryo-EM structure of the Blastochloris viridis LH1-RC complex at 2.9 angstrom.
Qian, P., Siebert, C.A., Wang, P., Canniffe, D.P., Hunter, C.N.(2018) Nature 556: 203-208
- PubMed: 29618818
- DOI: https://doi.org/10.1038/s41586-018-0014-5
- Primary Citation of Related Structures:
6ET5 - PubMed Abstract:
The light-harvesting 1-reaction centre (LH1-RC) complex is a key functional component of bacterial photosynthesis. Here we present a 2.9 Å resolution cryo-electron microscopy structure of the bacteriochlorophyll b-based LH1-RC complex from Blastochloris viridis that reveals the structural basis for absorption of infrared light and the molecular mechanism of quinone migration across the LH1 complex. The triple-ring LH1 complex comprises a circular array of 17 β-polypeptides sandwiched between 17 α- and 16 γ-polypeptides. Tight packing of the γ-apoproteins between β-polypeptides collectively interlocks and stabilizes the LH1 structure; this, together with the short Mg-Mg distances of bacteriochlorophyll b pairs, contributes to the large redshift of bacteriochlorophyll b absorption. The 'missing' 17th γ-polypeptide creates a pore in the LH1 ring, and an adjacent binding pocket provides a folding template for a quinone, Q P , which adopts a compact, export-ready conformation before passage through the pore and eventual diffusion to the cytochrome bc 1 complex.
Organizational Affiliation:
Department of Molecular Biology and Biotechnology, University of Sheffield, Sheffield, UK.
