NMR conformational studies on a synthetic peptide reproducing the [1-20] processing domain of the pro-ocytocin-neurophysin precursor.
The combined use of several nuclear magnetic resonance and restrained molecular dynamics techniques allowed the formulation of a molecular model for the preferred solution conformation of a synthetic peptide reproducing the [1-20] processing domain of the pro-ocytocin-neurophysin precursor. In the model, the conformation of the 20-membered tocin ring, with the two Cys1 and Cys6 residues bridged by a disulphide bond, is very close to that observed for isolated ocytocin in the solid state; in addition, a type II beta-turn is postulated for the 7-10 segment of the acyclic tail containing the Lys11-Arg12 processing site, and connecting ocytocin to the neurophysin domain, while the C-terminal 13-20 segment of the molecule is believed to assume a helical structure. This particular structural organization could be important in participating as the favorable conformation for optimal substrate-enzyme active site recognition and processing by specific endoproteases.
Falcigno
L
L
Department of Chemistry, University of Naples, Italy.
Paolillo
L
L
D'Auria
G
G
Saviano
M
M
Simonetti
M
M
Di Bello
C
C
D000595:Amino Acid Sequence; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009481:Neurophysins / Q000737:chemistry*; D010121:Oxytocin / Q000737:chemistry*; D011487:Protein Conformation; D011498:Protein Precursors / Q000737:chemistry*; D017434:Protein Structure, Tertiary
D009481:Neurophysins; D011498:Protein Precursors; D010121:Oxytocin