SEQUENTIAL ASSIGNMENT OF H-1, C-13 AND N-15 RESONANCES OF HUMAN CARBONIC-ANHYDRASE-I BY TRIPLE-RESONANCE NMR TECHNIQUES AND EXTENSIVE AMINOACID-SPECIFIC N-15-LABELING

The backbone NMR resonances of human carbonic anhydrase I (HCA I) have been assigned. This protein is one of the largest monomeric proteins assigned so far. The assignment was enabled by a combination of 3D tri ple-resonance experiments and extensive use of amino acid-specific N-1 5-labeling. The obtained resonance assignment has been used to evaluat e the secondary structure elements present in solution. The solution s tructure appears to be very similar to the crystal structure, although some differences can be observed. Proton-deuteron exchange experiment s have shown that the assignments provide probes that can be used in f uture folding studies of HCA I.