Solution conformation of tuftsin.
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.
D'Ursi
A
A
Dipartimento di Chimica, Università di Napoli, Italy.
Pegna
M
M
Amodeo
P
P
Molinari
H
H
Verdini
A
A
Zetta
L
L
Temussi
P A
PA
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*
D002247:Carbon Isotopes; D011522:Protons; D012996:Solutions; D014405:Tuftsin