A structural basis for long-range coupling in azurins from resonance Raman spectroscopy

The resonance Raman spectra of four structurally characterized azurins, an analogous blue copper protein, from three species of bacteria, Alcaligenes denitrificans, Pseudomonas aeruginosa and Alcaligenes xylosoxidans are reported. Similar frequencies but substantially different intensity patterns were observed from the spectra. Results provide a strong basis for the interpretation of observed resonance Raman intensity differences and frequency shifts arising from the coupling between the active site and the surrounding protein matrix.