Conformational analysis of peptide T and of its C-pentapeptide fragment.
The synthetic peptide of sequence H-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-OH, termed peptide T, a competitor of the Human Immunodeficiency Virus in the binding to human T cells, and its C-terminal pentapeptide fragment, were studied by 1H-nmr in DMSO solution to determine conformational preferences. The observation of nuclear Overhauser enhancements (NOEs) for both peptides, and unusual finding for small linear peptides, allowed complete sequence-specific resonance assignments. Long-range NOEs, ring-current shifts, and the very small temperature coefficient of the Thr8 NH chemical shift suggest, for the zwitterionic form of peptide T, the presence in solution of a beta-turn involving Thr5, Asn6, Tyr7 and Thr8. This conformational feature is consistent with previous structure-activity relationship studies indicating the invariance of the same residues in several potent pentapeptide analogues. The studied pentapeptide fragment, although less structured, shows some tendency to fold even in a polar solvent such as DMSO. Preliminary chemotaxis data on some pentapeptide analogues are consistent with our structural model.
Motta
A
A
Picone
D
D
Temussi
P A
PA
Marastoni
M
M
Tomatis
R
R
D006678:HIV; D008958:Models, Molecular; D009842:Oligopeptides; D015717:Peptide T; D011487:Protein Conformation; D012191:Retroviridae Proteins
D009842:Oligopeptides; D012191:Retroviridae Proteins; D015717:Peptide T