title: 1H-NMR and 13C-NMR investigation of complexes of Mn2+ with ocytocin analogues in (2H6)dimethylsulfoxide.
abstract: Several ocytocin analogues were synthesised by substitution of the Pro residue with sarcosine or N-methylalanine, the glutamine residue with threonine and one of the cysteines with 2-mercaptopropionic acid. All the derivatives were investigated by NMR in dimethylsulfoxide solutions and evidence was obtained for similar preferred conformations in the solution free state. All peptides were shown to form complexes with Mn2+ in solution by the strong paramagnetic effects experienced by several proton resonances. Two structures could be determined, one formed by peptides containing threonine and the other by the remaining peptides. The two structures were delineated by molecular modelling using the Mn(2+)-proton distances obtained by NMR as restraints.
authors.affiliation: Department of Chemistry, University of Siena, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Valensin
authors.forename: A
authors.initials: A
authors.lastname: Maccotta
authors.forename: E
authors.initials: E
authors.lastname: Gaggelli
authors.forename: Z
authors.initials: Z
authors.lastname: Grzonka
authors.forename: F
authors.initials: F
authors.lastname: Kasprzykowski
authors.forename: H
authors.initials: H
authors.lastname: Kozlowski
mesh_terms: D000409:Alanine / Q000031:analogs & derivatives; D000595:Amino Acid Sequence; D001665:Binding Sites; D002247:Carbon Isotopes; D003545:Cysteine; D003903:Deuterium; D004121:Dimethyl Sulfoxide; D005973:Glutamine; D006859:Hydrogen; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008345:Manganese / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010121:Oxytocin / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry*; D011392:Proline; D011485:Protein Binding; D011487:Protein Conformation; D012521:Sarcosine; D013438:Sulfhydryl Compounds; D013816:Thermodynamics; D013912:Threonine
chemical_list: D002247:Carbon Isotopes; D013438:Sulfhydryl Compounds; D005973:Glutamine; D013912:Threonine; D008345:Manganese; D010121:Oxytocin; C008408:N-methylalanine; D006859:Hydrogen; D011392:Proline; D003903:Deuterium; D003545:Cysteine; C023884:thiolactic acid; D000409:Alanine; D004121:Dimethyl Sulfoxide; D012521:Sarcosine