title: Number and placement of hydrophobic residues in a longitudinal strip governs helix formation of peptides in the presence of lipid vesicles.
abstract: alpha-Helix formation of a peptidyl sequence is stabilized by hydrophobic residues recurring at positions which create a longitudinal hydrophobic strip upon folding of the sequence as a helix against a hydrophobic surface. To test that hypothesis, we measured by circular dichroism the helical coiling on lipid vesicles of nine analogs of a prototypic helix peptide PH-1.0, Leu-Tyr-Gln-Glu-Leu-Gln-Lys-Leu-Thr-Gln-Thr-Leu-Lys. In these analogs, Thr was substituted for 1 or 2 Leu residues in the longitudinal hydrophobic strip Leu1...Leu5..Leu8...Leu12 which forms in the alpha-helical configuration. We found that coiling of analogs of Leu-Tyr-Gln-Glu-Leu-Gln-Lys-Leu-Tyr-Gln-Thr-Leu-Lys on lipid vesicles depends upon the strength and structure of its longitudinal hydrophobic strip.
authors.affiliation: Department of Pharmacology, University of Massachusetts Medical School, Worcester 01655.
authors.forename: S
authors.initials: S
authors.lastname: Lu
authors.forename: T
authors.initials: T
authors.lastname: Ciardelli
authors.forename: V E
authors.initials: VE
authors.lastname: Reyes
authors.forename: R E
authors.initials: RE
authors.lastname: Humphreys
mesh_terms: D000595:Amino Acid Sequence; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000235:genetics; D011487:Protein Conformation
chemical_list: D010455:Peptides