title: Trifluoroethanol induces the self-association of specific amphipathic peptides.
abstract: We have examined the effect of trifluoroethanol (TFE) on the solution behaviour of three amphipathic peptides. One of the peptides, containing three heptad repeat units (Ac-YS-(AKEAAKE)3GAR-NH2), remained monomeric under conditions where TFE induced a two-state transition from a random coil to an alpha-helix. In contrast, the TFE-induced alpha-helical formation of two peptides derived from human apolipoproteins C-II and E was accompanied by the formation of discrete dimers and trimers, respectively. The apolipoprotein C-II peptide further aggregated to form beta-sheet at higher concentrations of TFE (50% v/v). The results suggest a class of peptides capable of discrete self-association in the presence of cosolvents which favour intramolecular hydrogen bonding.
authors.affiliation: Russell Grimwade School of Biochemistry and Molecular Biology, University of Melbourne, Parkville, Vic., Australia.
authors.forename: C E
authors.initials: CE
authors.lastname: MacPhee
authors.forename: M A
authors.initials: MA
authors.lastname: Perugini
authors.forename: W H
authors.initials: WH
authors.lastname: Sawyer
authors.forename: G J
authors.initials: GJ
authors.lastname: Howlett
mesh_terms: D000595:Amino Acid Sequence; D053304:Apolipoprotein C-II; D001056:Apolipoproteins C / Q000737:chemistry* / Q000187:drug effects; D001057:Apolipoproteins E / Q000737:chemistry* / Q000187:drug effects; D002942:Circular Dichroism; D006801:Humans; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry* / Q000187:drug effects; D010455:Peptides / Q000737:chemistry* / Q000187:drug effects; D017433:Protein Structure, Secondary; D014270:Trifluoroethanol / Q000494:pharmacology*; D014783:Viscosity
chemical_list: D053304:Apolipoprotein C-II; D001056:Apolipoproteins C; D001057:Apolipoproteins E; D010446:Peptide Fragments; D010455:Peptides; D014270:Trifluoroethanol