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 journalArticle

455 Scopus citations

Abstract

Short peptides that contain significant α-helical structure in aqueous solution allow the investigation of the role of amino acid side chains in stabilizing or destabilizing α-helix structure. A host-guest system of soluble synthetic peptides was designed that consisted of chains with the block sequence TyrSerGlu4Lys4X3Glu 4Lys4, 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 > Ile > Val > Ser > Thr > Asn > Gly. This order differs from both host-guest copolymer values (Met > Ile > 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 > Ile > Val > Asn, Thr > Ser > Gly), but matches the order found in a series of synthetic coiled-coil α helices, 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
JournalScience
Volume250
Issue number4981
DOIs
StatePublished - 1990
Externally publishedYes

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