title: Structural characterization of the [Pco/o(2)] compound of cytochrome c oxidase.
abstract: The structural properties of a key transient oxygen intermediate of cytochrome c oxidase, P(R), remain an enigma, although inferences have been drawn from its equilibrium analogues, [Pco/o(2)] , P(H) and P(M). With resonance Raman spectroscopy, an oxygen isotope-sensitive band at 806 cm(-1) was observed in [Pco/o(2)] produced by adding CO and O(2) to the resting enzyme. The vibrational band shifted to 771 cm(-1) upon isotopic substitution of (16)O(2) with (18)O(2). The same modes at 806 and 771 cm(-1) were present simultaneously when the mixed isotope, (18)O(16)O, was employed, indicating that in [Pco/o(2)] the O-O bond is cleaved, resulting in a Fe(4+)O(2-) structure. This result unifies the nature of the three equilibrium analogues of the P(R) intermediate.
authors.affiliation: Department of Physiology and Biophysics, Albert Einstein College of Medicine of Yeshiva University, Bronx, NY 10461, USA.
authors.forename: Hong
authors.initials: H
authors.lastname: Ji
authors.forename: Syun-Ru
authors.initials: SR
authors.lastname: Yeh
authors.forename: Denis L
authors.initials: DL
authors.lastname: Rousseau
mesh_terms: D000818:Animals; D002248:Carbon Monoxide / Q000737:chemistry; D002417:Cattle; D003576:Electron Transport Complex IV / Q000737:chemistry*; D006418:Heme / Q000031:analogs & derivatives* / Q000737:chemistry; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry; D013059:Spectrum Analysis, Raman
chemical_list: C027728:heme a; D006418:Heme; D002248:Carbon Monoxide; D003576:Electron Transport Complex IV; D010100:Oxygen