CYCLO(-GLY-DSIP), A CYCLIC ANALOG OF THE DELTA-SLEEP-INDUCING PEPTIDE- COMPUTER-SIMULATION OF SPATIAL STRUCTURE INVOLVING NMR DATA

The spatial structure of cyclo(-Gly-DSIP-), a physiologically active a nalog of the delta sleep-inducing peptide, was determined by computer modelling using H-1 NMR data. An interesting feature of the spatial st ructure in DMSO was detected. One side of almost planar resulting conf ormation is formed by the side chains of the Asp(5), Ser(7) and Glu(9) residues, the side chain of the Trp(1) residue forming the other part of the outer surface; This feature may be associated with the functio nal properties of the peptide.