J. Biol. Chem., Vol. 266, Issue 16, 10054-10057, 06, 1991
Number and placement of hydrophobic residues in a longitudinal strip governs helix formation of peptides in the presence of lipid vesicles
S Lu, T Ciardelli, VE Reyes and RE Humphreys
Department of Pharmacology, University of Massachusetts Medical School, Worcester 01655.
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.