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Updated: Aug 15, 2026

T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
Published on: July 31, 2010
Intermonomer interactions in dimer of bovine heart cytochrome c oxidase
1Institute for Protein Research, Osaka University, 3-2 Yamada-oka, Suita 565-0871, Japan.
Abstract:
The X-ray structure of bovine heart cytochrome c oxidase solved for orthorhombic crystals showed a dimeric structure stabilized by four subunit-subunit contacts, namely, subunit Vb-subunit Vb on the matrix side, subunit I-subunit VIa, subunit VIa-subunit I in the transmembrane region and subunit VIb-subunit VIb on the intermembrane side. The same intermonomer contacts as in the orthorhombic crystals were observed in both hexagonal and tetragonal crystals, the X-ray structures of which were determined by the molecular-replacement method. These results suggest that the dimeric structure also exists under physiological conditions. These contacts, especially the subunit IVa-subunit I contact, in which the N-terminal portion of subunit IVa is placed on the surface of subunit I near the dioxygen-reduction site, indicate that the function of the bovine heart enzyme is likely to be controlled by perturbation of the monomer-monomer association.
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