title: 1H-NMR studies on arginine tripeptides: evidence for guanidinium-C-terminal carboxylate interactions.
abstract: Guanidinium-C-terminal carboxylate interactions are involved in the establishment of the secondary structure of various biologically active peptide sequences. The conformational properties of a series of arginine-containing tripeptides, L-Arg-X-Gly (X = L-Ala, Val, Leu), in DMSO solutions at physiological pH, have been studied by means of 1D and 2D 1H-NMR spectroscopy. Measurements of the chemical shifts, NOE effects and temperature coefficients showed that the ArgN epsilon H and ArgN eta H2 groups form two hydrogen bonds with the C-terminal carboxylate moiety, whereas the ArgN alpha-terminal nitrogen is in the amino state. Our results point out the significant contribution of the C-terminal carboxylate group, at physiological pH, in the stabilization of the Arg side-chain structure in peptides simultaneously containing arginine residues and carboxy terminal sequences.
authors.affiliation: University of Ioannina.
authors.forename: V
authors.initials: V
authors.lastname: Tsikaris
authors.forename: M
authors.initials: M
authors.lastname: Sakarellos-Daitśiotis
authors.forename: E
authors.initials: E
authors.lastname: Panou-Pomonis
authors.forename: E
authors.initials: E
authors.lastname: Detsikas
authors.forename: C
authors.initials: C
authors.lastname: Sakarellos
authors.forename: M T
authors.initials: MT
authors.lastname: Cung
authors.forename: M
authors.initials: M
authors.lastname: Marraud
mesh_terms: D000595:Amino Acid Sequence; D001120:Arginine / Q000737:chemistry* / Q000378:metabolism; D002264:Carboxylic Acids / Q000737:chemistry; D019791:Guanidine; D006146:Guanidines / Q000737:chemistry / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D002264:Carboxylic Acids; D006146:Guanidines; D010455:Peptides; D001120:Arginine; D019791:Guanidine