NMR-STUDIES OF SECONDARY STRUCTURE IN CALCIUM-BINDING HEXADECAPEPTIDE

The three-dimensional solution structure of the CaBP hexadecapeptide c ontaining the sequence of the IIId Ca-binding loop of calmodulin has b een determined by restrained molecular dynamics calculations based on experimental constraints derived from two-dimensional H-1 NMR spectra and supported by measurements of the exchange rates for backbone amide protons with solvent and the chemical shift index. All these methods prove that the peptide saturated with La3+ ions exhibits the alpha-hel ical conformation comprising seven amino acid residues of C-terminus.