Photoperturbation of the heme a3-CuB binuclear center of cytochrome c oxidase CO complex observed by Fourier transform infrared spectroscopy.
AUTOR(ES)
Park, S
RESUMO
Purified cytochrome c oxidase CO complex from beef heart has been studied by Fourier transform infrared absorbance difference spectroscopy. Photolysis at 10-20 Kelvin results in dissociation of a3FeCO, formation of CuBCO, and perturbation of the a3-heme and CuB complex. The vibrational perturbation spectrum between 900 and 1700 cm-1 contains a wealth of information about the binuclear center. Appearance in infrared photoperturbation difference spectra of virtually all bands previously reported from resonance Raman spectra indicate the importance of polarization along the 4-vinyl:8-formyl axis, which results in the reduction of heme symmetry to C2v. Frequency-shifted bands due to the 8-formyl and 4-vinyl groups of the a3-heme have been identified and quantitated. The frequency shifts have been interpreted as being due to a change in porphyrin polarization with change in spin state of the iron by photodissociation of CO or perturbation of the CuB coordination complex.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=1233558Documentos Relacionados
- Cytochrome oxidase (a3) heme and copper observed by low-temperature Fourier transform infrared spectroscopy of the CO complex.
- Definition of the catalytic site of cytochrome c oxidase: specific ligands of heme a and the heme a3-CuB center.
- Could CuB be the site of redox linkage in cytochrome c oxidase?
- pH-induced structural changes in bacteriorhodopsin studied by Fourier transform infrared spectroscopy.
- Determination of molecular order in supported lipid membranes by internal reflection Fourier transform infrared spectroscopy.
