title: Solution conformation of tuftsin.
abstract: Tuftsin, a natural linear tetrapeptide (Thr-Lys-Pro-Arg) of potential antitumor activity, has been studied in DMSO-d6 solution by 2D NMR spectroscopy. 1H and 13C spectra show the presence of two families of conformations characterized by a trans or cis Lys-Pro bond, respectively. The family of conformers containing the cis peptide bond is a mixture of extended structures as expected for a short linear peptide. On the contrary, the trans isomer appears to be a rigid, folded conformer, as indicated by crucial NOEs and by the exceptionally low temperature coefficient of Arg NH. Analysis of the solution data by means of energy calculations leads to a unique structure, characterized by a Lys-Pro inverse gamma-turn.
authors.affiliation: Dipartimento di Chimica, Università di Napoli, Italy.
authors.forename: A
authors.initials: A
authors.lastname: D'Ursi
authors.forename: M
authors.initials: M
authors.lastname: Pegna
authors.forename: P
authors.initials: P
authors.lastname: Amodeo
authors.forename: H
authors.initials: H
authors.lastname: Molinari
authors.forename: A
authors.initials: A
authors.lastname: Verdini
authors.forename: L
authors.initials: L
authors.lastname: Zetta
authors.forename: P A
authors.initials: PA
authors.lastname: Temussi
mesh_terms: D000595:Amino Acid Sequence; D002247:Carbon Isotopes; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D011522:Protons; D012996:Solutions; D014405:Tuftsin / Q000737:chemistry*
chemical_list: D002247:Carbon Isotopes; D011522:Protons; D012996:Solutions; D014405:Tuftsin