Structural basis for energy transduction by respiratory alternative complex III

Electron transfer in respiratory chains generates the electrochemical potential that serves as energy source for the cell. Prokaryotes can use a wide range of electron donors and acceptors and may have alternative complexes performing the same catalytic reactions as the mitochondrial complexes. This is the case for the alternative complex III (ACIII), a quinol:cytochrome c /HiPIP oxidoreductase. In order to understand the catalytic mechanism of this respiratory enzyme, we determined the structure of ACIII from Rhodothermus marinus at 3.9 Å resolution by single-particle cryo-electron microscopy. ACIII presents a so-far unique structure, for which we establish the arrangement of the cofactors (four iron–sulfur clusters and six c -type hemes) and propose the location of the quinol-binding site and the presence of two putative proton pathways in the membrane. Altogether, this structure provides insights into a mechanism for energy transduction and introduces ACIII as a redox-driven proton pump.

Abstract licence: CC BY-NC-ND

1. 28.

   RELION: Implementation of a Bayesian approach to cryo-EM structure determination · 2012

2. 35.

   Features and development of Coot · 2010

3. 37.

   Beam-induced motion correction for sub-megadalton cryo-EM particles · 2014

4. 39.

   MolProbity : all-atom structure validation for macromolecular crystallography · 2009

36 more references, whose wording the paper’s licence keeps private.

A person counts once a day per paper. We keep no cookie and no address: a reader is a hash that changes every day. Any month under five reads shows no number.