A 1H nuclear magnetic resonance study of the opioid peptide dynorphin-(1–13) in aqueous solution

A 1H n.m.r. study of the conformation of the opioid peptide dynorphin-(1-13) was performed in aqueous solution using one-dimensional (1D) and two-dimensional (2D) n.m.r. techniques. Chemical shifts, scalar 3Jφ values, amide proton–deuteron exchange rates, temperature coefficients of chemical shifts, and spin-label perturbation of amide proton relaxation rates formed a self-consistent picture of a polypeptide chain possessing no major preferred secondary conformations. 600 MHz 2D J-resolved spectroscopy was used to analyse the coupling patterns for the consituent amino acid residues. Side-chain rotamer analysis based upon 3Jαβ coupling constants for five of the residues indicated no significantly large populations of any χ1 rotamers.