C-13 NMR-STUDY OF THE B9(ASP) MUTANT OF HUMAN INSULIN - SEQUENCE-SPECIFIC C-13 ASSIGNMENTS AND STRUCTURAL INFORMATION

The resonances of the proton-bearing C-13 nuclei at natural abundance were assigned for the solution dimer of the B9(Asp) mutant of human insulin. The assignments are based an a combination of direct and relayed H-1-C-13 correlated spectra, i.e. SQC, SQC-HOHAHA and HMQC-COSY, and the previously assigned H-1 spectrum. The study proves valuable not only because of the C-13 assignments, but also because it provides a verification, a completion and a few corrections of the previous H-1 assignments. Finally, the obtained C-13 assignments support the previously reported correlation between the secondary C-13(alpha) and C-13(beta) chemical shifts and the secondary structure of proteins.