Resonance Raman spectroscopy of amicyanin, a blue copper protein from Paracoccus denitrificans
The copper binding site of amicyanin from Paracoccus denitrificans has been examined by resonance Raman spectroscopy. The pattern of vibrational modes is clearly similar to those of the blue copper proteins azurin and plastocyanin. Intense resonance-enhanced peaks are observed at 377, 392, and 430 cm-1 as well as weaker overtones and combination bands in the high frequency region. Most of the peaks below 500 cm-1 shift 0.5-1.5 cm-1 to lower energy when the protein is exposed to D/sub 2/O. Based on the pattern of conserved amino acids, the axial type EPR spectrum, and the resonance Raman spectrum, it is proposed that the copper binding site in amicyanin contains a Cu(II) ion in a distorted trigonal planar geometry with one cysteine and two histidine ligands and an axial methionine ligand at a considerably longer distance. Furthermore, the presence of multiple intense Raman peaks in the 400 cm-1 region which are sensitive to deuterium substitution leads to the conclusion that the Cu-S stretch is coupled with internal ligand vibrational modes and that the sulfur of the cysteine ligand is likely to be hydrogen-bonded to the polypeptide backbone.
- Research Organization:
- Oregon Graduate Center, Beaverton (USA)
- OSTI ID:
- 5176105
- Journal Information:
- J. Biol. Chem.; (United States), Vol. 263:7
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
COPPER
RECEPTORS
METALLOPROTEINS
RAMAN SPECTRA
CYSTEINE
DEUTERIUM
ELECTRON SPIN RESONANCE
LIGANDS
TRACER TECHNIQUES
AMINO ACIDS
CARBOXYLIC ACIDS
ELEMENTS
HYDROGEN ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
LIGHT NUCLEI
MAGNETIC RESONANCE
MEMBRANE PROTEINS
METALS
NUCLEI
ODD-ODD NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PROTEINS
RESONANCE
SPECTRA
STABLE ISOTOPES
THIOLS
TRANSITION ELEMENTS
550201* - Biochemistry- Tracer Techniques