Cooperative membrane insertion of magainin correlated with its cytolytic activity.
Using oriented circular dichroism, we have found that magainin adopts an alpha-helical conformation with two distinct orientations when interacting with a lipid bilayer. At low concentrations, magainin is absorbed parallel to the membrane surface. However, at high concentrations, magainin is inserted into the membrane. This transition occurs at roughly the same critical concentration required for cytolytic activity, implying that the membrane insertion is responsible for magainin's cell-lysing activity.
Ludtke
S J
SJ
Physics Department, Rice University, Houston, TX 77251-1892.
He
K
K
Wu
Y
Y
Huang
H W
HW
D000890:Anti-Infective Agents / Q000737:chemistry / Q000494:pharmacology*; D023181:Antimicrobial Cationic Peptides; D002463:Cell Membrane Permeability / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002942:Circular Dichroism; D004134:Dimyristoylphosphatidylcholine / Q000737:chemistry; D008051:Lipid Bilayers / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry / Q000494:pharmacology*; D010715:Phosphatidylglycerols / Q000737:chemistry; D011487:Protein Conformation; D029867:Xenopus Proteins
D000890:Anti-Infective Agents; D023181:Antimicrobial Cationic Peptides; D008051:Lipid Bilayers; D010455:Peptides; D010715:Phosphatidylglycerols; D029867:Xenopus Proteins; C053300:magainin 1 peptide, Xenopus; C002773:dimyristoylphosphatidylglycerol; D004134:Dimyristoylphosphatidylcholine