3cx5

File:3cx5.jpg

Structure of complex III with bound cytochrome c in reduced state and definition of a minimal core interface for electron transfer.

OverviewOverview

In cellular respiration, cytochrome c transfers electrons from cytochrome bc1 complex (complex III) to cytochrome c oxidase by transiently binding to the membrane proteins. Here, we report the structure of isoform-1 cytochrome c bound to cytochrome bc1 complex at 1.9-A resolution in reduced state. The dimer structure is asymmetric. Monovalent cytochrome c binding is correlated with conformational changes of the Rieske head domain and subunit QCR6p and with a higher number of interfacial water molecules bound to cytochrome c1. Pronounced hydration and a 'mobility mismatch' at the interface with disordered charged residues on the cytochrome c side are favourable for transient binding. Within the hydrophobic interface, a minimal core was identified by comparison with the novel structure of the complex with bound isoform-2 cytochrome c. Four core interactions encircle the heme cofactors surrounded by variable interactions. The core interface may be a feature to gain specificity for formation of the reactive complex.

About this StructureAbout this Structure

3CX5 is a Protein complex structure of sequences from Mus musculus and Saccharomyces cerevisiae. Full crystallographic information is available from OCA.

ReferenceReference

Structure of complex III with bound cytochrome c in reduced state and definition of a minimal core interface for electron transfer., Solmaz S, Hunte C, J Biol Chem. 2008 Apr 4;. PMID:18390544 Page seeded by OCA on Wed May 14 11:34:40 2008