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Conformational analysis of peptide T and of its C‐pentapeptide fragment
Author(s) -
Motta Andrea,
Picone Delia,
Temussi Piero A.,
Marastoni Mauro,
Tomatis Roberto
Publication year - 1989
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.360280142
Subject(s) - pentapeptide repeat , chemistry , peptide , stereochemistry , sequence (biology) , cyclic peptide , chemotaxis , biochemistry , receptor
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 1 H‐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 Thr 8 NH chemical shift suggest, for the zwitterionic form of peptide T, the presence in solution of a β‐turn involving Thr 5 , Asn 6 , Tyr 7 and Thr 8 . 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.