Number and placement of hydrophobic residues in a longitudinal strip governs helix formation of peptides in the presence of lipid vesicles.
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.
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Department of Pharmacology, University of Massachusetts Medical School, Worcester 01655.
Ciardelli
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Reyes
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Humphreys
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D000595:Amino Acid Sequence; D002942:Circular Dichroism; D008969:Molecular Sequence Data; D010455:Peptides / Q000138:chemical synthesis* / Q000235:genetics; D011487:Protein Conformation
D010455:Peptides