Structure of Cytochrome cOxidase fromParacoccus denitrificans at 2.8Å Resolution

Abstract

The crystal structure of cytochrome c oxidase from Paracoccus denitrificans at 2.8Å resolution is described. The crystallization of this membrane protein complex is achieved by co-crystallization with antibody Fv-fragment. The enzyme contains four subunits. Subunit I contains twelve tranmembrane helices and binds heme a and the heme a₃-copper B binuclear center where molecular oxygen is reduced to water. Two proton transfer pathways, one for protons consumed in water formation and one for‘proton pumping’could be identified. A possible mechanism for proton pumping is discussed.