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Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
ATR-FTIR difference spectroscopy of the P(M) intermediate of bovine cytochrome c oxidase
Masayo Iwaki1, Jacques Breton, Peter R Rich
1The Glynn Laboratory of Bioenergetics, Department of Biology, University College London, UK.
Abstract:
Perfusion-induced attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy was used to investigate changes induced in protein and cofactors of bovine cytochrome c oxidase when it was converted from the oxidised state to the catalytic P(M) intermediate. The transition was induced in a film of detergent-depleted 'fast' oxidase with a buffer containing CO and O(2). The extent of formation of the P(M) state was quantitated simultaneously by monitoring formation of its characteristic 607-nm band with a scanned visible beam reflected off the top surface of the prism. The P(M) minus O FTIR difference spectrum is distinctly different from the redox spectra reported to date and includes features that can be assigned to changes of haem a(3) and surrounding protein. Tentative assignments are made based on vibrational data of related proteins and model compounds.
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