title: Comparing conformations at low temperature and at high viscosity. Conformational study of somatostatin and two of its analogues in methanol and in ethylene glycol.
abstract: The influence of low temperature and high viscosity on the conformation of somatostatin and two of its analogues was investigated by 1H NMR in solution. The conformation of native somatostatin, a cyclic octapeptide agonist DC13-116 and a linear octapeptide agonist were compared in ethylene glycol at 303 K and in methanol at low temperature. The first goal of this study was to investigate if either low temperature or high viscosity is the more important for the reduction of the conformational freedom. Secondly we wanted to compare the amount of information concerning the conformation present in both solvents. A larger amount of NOESY cross-peaks is observed in ethylene glycol at room temperature compared to methanol at low temperature. This indicates that the raising of the viscosity is a more important factor in reducing the flexibility of peptides than the lowering of the temperature.
authors.affiliation: Department of Organic Chemistry, Free University of Brussels, Belgium.
authors.forename: P
authors.initials: P
authors.lastname: Verheyden
authors.forename: E
authors.initials: E
authors.lastname: De Wolf
authors.forename: H
authors.initials: H
authors.lastname: Jaspers
authors.forename: G
authors.initials: G
authors.lastname: Van Binst
mesh_terms: D000595:Amino Acid Sequence; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D003080:Cold Temperature; D019855:Ethylene Glycol; D005026:Ethylene Glycols / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D000432:Methanol / Q000737:chemistry*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry; D010456:Peptides, Cyclic / Q000737:chemistry; D011487:Protein Conformation; D017433:Protein Structure, Secondary; D012996:Solutions; D013004:Somatostatin / Q000031:analogs & derivatives* / Q000737:chemistry*; D014783:Viscosity
chemical_list: D005026:Ethylene Glycols; D009842:Oligopeptides; D010456:Peptides, Cyclic; D012996:Solutions; C092678:phenylalanyl-chlorophenylalanyl-tyrosyl-tryptophyl-lysyl-valyl-phenylalanyl-threoninamide; C060347:lanreotide; D013004:Somatostatin; D019855:Ethylene Glycol; D000432:Methanol