Paramagnetic NMR spectroscopy and coordination structure of cobalt(II) Cys112Asp azurin

Experimental study enables the assignment of hyperfine-shifted signals of the paramagnetic 1H NMR spectra of Co(II)-substituted Cys112 Asp azurin from Pseudomonas aeruginosa for all the coordinated groups. Spectral studies show little or no localization of unpaired spin density on Met 121 protons of the Cys112 Asp protein. The interpretation of electronic absorption and NMR data is confirmed by a computerized model that visualizes Asp112 and His117 in the ligation sphere and the presence of Gly45 carbonyl and His46.