title: A model for cytochrome oxidase.
abstract: A model is proposed for the active center of cytochrome c oxidase (ferrocytochrome c:oxygen oxidoreductase, EC 1.9.3.1) in which cytochrome a is a low-spin ferrihemoprotein and cytochrome a3 is a high-spin ferrihemoprotein antiferromagnetically coupled to one of the two Cu2+ ions present in the enzyme. It is further proposed that reduction is accompanied by a conformational change in the enzyme thus exposing the sixth coordination site of cytochrome a3 to ligands. With this model it is possible to account for a variety of outstanding observations including the results of magnetic circular dichroism, Mossbauer, and electron paramagnetic resonance spectroscopies, as well as magnetic susceptibility measurements.
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D003300:Copper; D004578:Electron Spin Resonance Spectroscopy; D003576:Electron Transport Complex IV; D006420:Hemeproteins; D008024:Ligands; D008280:Magnetics; D008961:Models, Structural; D011487:Protein Conformation
chemical_list: D006420:Hemeproteins; D008024:Ligands; D003300:Copper; D003576:Electron Transport Complex IV