title: Oxygen activation and reduction in respiration: involvement of redox-active tyrosine 244.
abstract: Cytochrome oxidase activates and reduces O(2) to water to sustain respiration and uses the energy released to drive proton translocation and adenosine 5'-triphosphate synthesis. A key intermediate in this process, P, lies at the junction of the O(2)-reducing and proton-pumping functions. We used radioactive iodide labeling followed by peptide mapping to gain insight into the structure of P. We show that the cross-linked histidine 240-tyrosine 244 (His240-Tyr244) species is redox active in P formation, which establishes its structure as Fe(IV) = O/Cu(B)2+-H240-Y244. Thus, energy transfer from O2 to the protein moiety is used as a strategy to avoid toxic intermediates and to control energy utilization in subsequent proton-pumping events.
authors.affiliation: Department of Chemistry and Department of Biochemistry, Michigan State University, East Lansing, MI 48824, USA.
authors.forename: D A
authors.initials: DA
authors.lastname: Proshlyakov
authors.forename: M A
authors.initials: MA
authors.lastname: Pressler
authors.forename: C
authors.initials: C
authors.lastname: DeMaso
authors.forename: J F
authors.initials: JF
authors.lastname: Leykam
authors.forename: D L
authors.initials: DL
authors.lastname: DeWitt
authors.forename: G T
authors.initials: GT
authors.lastname: Babcock
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D019281:Dimerization; D003576:Electron Transport Complex IV / Q000737:chemistry* / Q000378:metabolism*; D006639:Histidine / Q000737:chemistry / Q000378:metabolism; D007457:Iodine Radioisotopes; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D010449:Peptide Mapping; D017494:Proton Pumps; D014443:Tyrosine / Q000737:chemistry / Q000378:metabolism*
chemical_list: D007457:Iodine Radioisotopes; D010446:Peptide Fragments; D017494:Proton Pumps; D014443:Tyrosine; D006639:Histidine; D003576:Electron Transport Complex IV; D010100:Oxygen