Conformational analysis of a novel cyclic enkephalin analogue using NMR and EDMC calculations

Conformational space of a novel cyclic enkephalin analogue, cyclo(N-epsilon ,N-epsilon'-carbonyl-D-Lys(2),Lys(5))enkephalinamide, was exhaustively exam ined. A large number of conformations was selected and clustered into famil ies on the basis of their structure and energy. For representative conforma tions ROESY spectra were generated and their linear combination was fitted to the spectra measured in water and Me2SO-d(6). This procedure yielded an ensemble of most populated conformations of the peptide in the two solvents .