Hexapeptide analogue of somatostatin, Sandoz 201-456. Conformational study in dimethylsulfoxide by 1D and 2D n.m.r. methods.
The conformational properties of the somatostatin analogue 201-456 (1) have been studied by high field n.m.r. in DMSO. This analogue is the base structure of nine derivates synthesized by Bauer et al. and shows a very low biological activity, although derived structures such as SMS 201-995 (2) are very potent. Our study has shown an important difference between the most stable conformation of the two compounds: although the beta turn type II' structure at the Phe3-Trp4-Lys5 level is present in both analogues, an important conformational change appears at the cystine bridge. In SMS 201-995 the beta turn/beta sheet conformation is stabilized by the additional amino-acids D-Phe1 and Thr8 (ol) through intramolecular H-bonds.
Wynants
C
C
Van Binst
G
G
Loosli
H R
HR
D000595:Amino Acid Sequence; D004121:Dimethyl Sulfoxide; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D011487:Protein Conformation; D013004:Somatostatin / Q000031:analogs & derivatives*
D013004:Somatostatin; C046526:San 201-456; D004121:Dimethyl Sulfoxide