Strategies of signal assignments in paramagnetic metalloproteins. An NMR investigation of the thiocyanate adduct of the cobalt (II)-substituted human carbonic anhydrase II.

The title protein with MW 30,000 containing high-spin cobalt (II) has been thoroughly investigated through 1H NMR spectroscopy with the aid of selectively deuterated amino acids and 15N enrichment. The aim is that of showing the potentiality of the approach when local information by NMR is needed and the X-ray structure is available. The potential use of the pseudocontact shift is discussed; 90, 200, and 600 MHz spectrometers are used to investigate a spherical region at various distances from the metal ion. More than 35 signals of protons around cobalt (II) have been assigned.