At least 154 of the expected-210 13C0-'3C, correlations were resolved by using the software package MADNMR.* This suggests that uniform I3C labeling will support a heteronuclear approach to sequence-specific resonance assignments. The I3C-l3C correlations, in combination with multiple-bond 13C-IH correlations or I3C-l5N correlations from dual 13C/'SN-labeled proteins, or both, can be used to trace out the peptide backbone ...