Side chain contributions to the stability of alpha-helical structure in peptides

Pingchiang C. Lyu, Mark I. Liff, Luis A. Marky, Neville R. Kallenbach

Research output: Contribution to journalArticlepeer-review


Short peptidcs that contain significant α-helical structure in aqueous solution allow the investigation of the role of amino acid side chains in stabilizing or destabilizing ahelix structure. A host-guest system of soluble synthetic peptides was designed that consisted of chains with the block sequence TyrSerGlu4LyS4X3Glu4LyS4, denoted EXK, in which X represents any "guest" amino acid residue. Circular dichroism spectroscopy indicates that the extent of helicity of these peptides follows the order Ala > Leu > Met > Gln > He > Val > Ser > Thr > Asn > Gly. This order differs from both hostguest copolymer values (Met > Iie > Leu > Ala > Gln > Val > Thr > Asn > Ser > Gly) and the tendencies of these amino acids to occur in helices in globular proteins (Ala > Met > Leu > Gln > He > Val > Asn, Thr > Ser > Gly), but matches the order found in a series of synthetic coiled-coil αhelices, except for Ser. Proton nuclear magnetic resonance analysis of several EXK peptides indicates that these peptides are partially helical, with the helical residues favoring the amino terminus.

Original languageEnglish (US)
Pages (from-to)669-673
Number of pages5
Issue number4981
StatePublished - Nov 2 1990

ASJC Scopus subject areas

  • General


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