Two-dimensional 1H-NMR and CD structural analysis in a micellar medium of a bovine alphaS1-casein fragment having benzodiazepine-like properties.
The conformation of the benzodiazepine-like decapeptide, YLGYLEQLLR, corresponding to residues 91-100 of bovine alphaS1-casein, has been examined in SDS micelles using CD, two-dimensional 1H-NMR and restrained molecular-dynamics simulation. Evidence is presented that the decapeptide adopts a rigid structure in water/SDS micellar medium, but not in water or dimethylsulfoxide. The three-dimensional structure, consistent with the proton-proton distances obtained from the quantitative analysis of the two-dimensional NOEs, was generated by restrained energy minimization and molecular-dynamics simulation. In water/SDS micellar medium, YLGYLEQLLR adopts an amphipathic helicoid structure with distinct hydrophobic and hydrophilic faces. The relative disposition of the tyrosine aromatic rings was compared with that of the aromatic rings in the benzodiazepines.
Lecouvey
M
M
Laboratoire de Chimie Physique Macromoléculaire, CNRS-URA 494, ENSIC-INPL, Nancy, France.
Frochot
C
C
Miclo
L
L
Orlewski
P
P
Driou
A
A
Linden
G
G
Gaillard
J L
JL
Marraud
M
M
Cung
M T
MT
Vanderesse
R
R
D000818:Animals; D001569:Benzodiazepines / Q000494:pharmacology*; D002364:Caseins / Q000737:chemistry* / Q000494:pharmacology*; D002417:Cattle; D002942:Circular Dichroism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008958:Models, Molecular; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry* / Q000494:pharmacology*; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D014443:Tyrosine / Q000737:chemistry; D014867:Water
D002364:Caseins; D008823:Micelles; D010446:Peptide Fragments; D014867:Water; D001569:Benzodiazepines; D012967:Sodium Dodecyl Sulfate; D014443:Tyrosine; D004121:Dimethyl Sulfoxide