title: Conformational analysis of the biologically active cyclic analog of beta-casomorphin H-Tyr-cyclo[D-OrnPheProGly].
abstract: A biologically active analog of beta-casomorphin, H-Tyr-cyclo[D-OrnPheProGly], was studied by theoretical conformational analysis. Random sampling was used to search the conformational space of allowed dihedral angles. Among 53 low-energy conformers with different folding of the peptide cyclic moiety, only those were selected which correspond to the low-energy area of the model linear tripeptide Ac-D-AlaAlaPro-NHMe. This peptide was used as the main chain "template" for the D-OrnPheProGly fragment of the studied cyclopeptide molecule. Only 15 conformers were chosen as potentially biologically active structures. The conformational possibilities of the Phe residue were constrained to the combined (A + G) region of the Ala residue phi,psi-map for linear peptides.
authors.affiliation: Shemyakin and Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Russia. pkos@ibch.siobc.ras.ru
authors.forename: P V
authors.initials: PV
authors.lastname: Kostetsky
authors.forename: S F
authors.initials: SF
authors.lastname: Arkhipova
mesh_terms: D000595:Amino Acid Sequence; D002151:Calorimetry; D004723:Endorphins / Q000737:chemistry; D008958:Models, Molecular; D009842:Oligopeptides / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry*; D011487:Protein Conformation; D013329:Structure-Activity Relationship; D013816:Thermodynamics
chemical_list: D004723:Endorphins; D009842:Oligopeptides; D010456:Peptides, Cyclic; C086901:tyrosyl-cyclo(ornithyl-phenylalanyl-prolyl-glycyl-); C078889:acetylprolyl-alanyl-alanine-N-methylamide; C021968:beta-casomorphins