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Conformational Comparison of Cyclic &#945;<sub>3</sub>&#946; Tetrapeptide vs. &#945;<sub>3</sub>&#946; Pentapeptide


SA Pawara
AM Jabgunde
GEM Maguire
DD Dhavale
HG Kruger
F Albericio

Abstract

The γ-turn inducing sugar β-amino acid plays an important role in the formation of well-defined secondary structures of cyclic tetra- and pentapeptide. Two tetra- and one novel pentapeptide were synthesized from a sugar β-amino acid and the conformations of the compounds were established by NMR spectroscopy (EASY-ROESY) and compared with CD spectroscopic data. Although the ã-turn conformation was dominant for both tetra- and pentapeptide according to NMR spectroscopic analysis in DMSO, the pentapeptide exhibited the  presence of a second conformation.CDspectroscopic results in methanol showed that the tetrapeptides have a γ-turn conformation, while the pentapeptide has a random structure.

KEYWORDS: Cyclic peptide, tetrapeptide, pentapeptide, conformational analysis, NMR spectroscopy, CD spectroscopy.


Journal Identifiers


eISSN: 1996-840X
print ISSN: 0379-4350