Preliminary analysis of 1H and 13C spectral and relaxation behavior in methionine-enkephalin.

Publisher Website
Google Scholar
Abstract
NMR studies on the conformational dynamics of the pentapeptide H-Tyr-Gly-Gly-Phe-Met-OH are reported. This peptide, for which the generic trivial name methionine-enkephalin has been suggested, is pharmacologically active as a ligand for the mammalian opiate receptor(s). The studies reported are parallel investigations in 2 solvents (dimethylsulfoxide and H2O) of 1H and 13C high resolution spectral assignments; 1H and 13C spin-lattice relaxation times, temperature dependence of amide proton chemical shifts and half-times for chemical exchange or amide protons. The tyrosine side chain of methionine-enkephalin exhibits restricted motion with respect to the main peptide backbone of the molecule. Both the phenylalanyl and methionyl side chains are undergoing intramolecular reorientation with relatively high frequency.