Relationship between 1H and 13C NMR chemical shifts and the secondary and tertiary structure of a zinc finger peptide.

Essentially complete assignments have been obtained for the 1H and protonated 13C NMR spectra of the zinc finger peptide Xfin-31 in the presence and absence of zinc. The patterns observed for the 1H and 13C chemical shifts of the peptide in the presence of zinc, relative to the shifts in the absence of zinc, reflect the zinc-mediated folding of the unstructured peptide into a compact globular structure with distinct elements of secondary structure. Chemical shifts calculated from the 3D solution structure of the peptide in the presence of zinc and the observed shifts agree to within ca. 0.2 and 0.6 ppm for the backbone C alpha H and NH protons, respectively. In addition, homologous zinc finger proteins exhibit similar correlations between their 1H chemical shifts and secondary structure.