title: Kinetics of cytochrome c oxidase from R. sphaeroides initiated by direct electron transfer followed by tr-SEIRAS.
abstract: Time-resolved surface-enhanced IR-absorption spectroscopy (tr-SEIRAS) has been performed on cytochrome c oxidase from Rhodobacter sphaeroides. The enzyme was converted electrochemically into the fully reduced state. Thereafter, in the presence of oxygen, the potential was switched to open circuit potential (OCP). Under these conditions, the enzyme is free to undergo enzymatic oxidation in the absence of an external electric field. Tr-SEIRAS was performed using the step-scan technique, triggered by periodic potential pulses switching between - 800mV and OCP. Single bands were resolved in a broad band in the amide I region using phase sensitive detection. Amplitudes of these bands were analyzed as a function of time. Time constants in the ms time scale were considered in terms of conformational changes of the protein secondary structures associated with the enzymatic turnover of the protein.
authors.affiliation: Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City Str. 1, 1220 Vienna, Austria.
authors.forename: Christoph
authors.initials: C
authors.lastname: Steininger
authors.affiliation: Center of electrochemical Surface Technology, CEST, Viktor-Kaplan-Str. 2, 2700 Wiener Neustadt, Austria.
authors.forename: Ciril
authors.initials: C
authors.lastname: Reiner-Rozman
authors.affiliation: Institute of Chemical Technologies and Analytics, Vienna University of Technology, Getreidemarkt 9, 1060 Vienna, Austria.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schwaighofer
authors.affiliation: Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City Str. 1, 1220 Vienna, Austria.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Knoll
authors.affiliation: Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City Str. 1, 1220 Vienna, Austria. Electronic address: kontakt@rlc-naumann.eu.
authors.forename: Renate L C
authors.initials: RL
authors.lastname: Naumann
mesh_terms: D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism*; D055767:Immobilized Proteins / Q000737:chemistry / Q000378:metabolism; D007700:Kinetics; D008958:Models, Molecular; D011487:Protein Conformation; D012242:Rhodobacter sphaeroides / Q000201:enzymology*; D013055:Spectrophotometry, Infrared
chemical_list: D055767:Immobilized Proteins; D003576:Electron Transport Complex IV
keywords: Conformational transitions; Cytochrome c oxidase; Electrochemically modulated spectroscopy; Fourier transform infrared spectroscopy; Membrane proteins; Surface-enhanced infrared-absorption spectroscopy