Membrane interactions and surface hydrophobicity of Bacillus thuringiensis delta-endotoxin CryIC.
The interaction between Bacillus thuringiensis insecticidal delta-endotoxin CryIC and phospholipid vesicles was studied by fluorescence spectroscopy. The toxin dissipates the diffusion potential across vesicular membranes, presumably by creating ion permeable channels or pores. This effect is pH-dependent and strongly increases under acidic conditions. The enhanced membrane-perturbing activity of CryIC at low pH correlates with the increased surface hydrophobicity of the toxin molecule. The membrane permeabilizing effect of the toxin is further increased by the presence of acidic phospholipids. These findings are discussed in relation to the mode of insecticidal action of the toxin.
Butko
P
P
Institute for Biological Sciences, National Research Council, Ottawa, Ontario, Canada.
Cournoyer
M
M
Pusztai-Carey
M
M
Surewicz
W K
WK
D000817:Anilino Naphthalenesulfonates; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001427:Bacterial Toxins; D004731:Endotoxins / Q000737:chemistry / Q000378:metabolism*; D005456:Fluorescent Dyes; D006460:Hemolysin Proteins; D006863:Hydrogen-Ion Concentration; D008564:Membrane Potentials; D010572:Pest Control, Biological; D010743:Phospholipids / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D000817:Anilino Naphthalenesulfonates; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D005456:Fluorescent Dyes; D006460:Hemolysin Proteins; D010743:Phospholipids; C030956:insecticidal crystal protein, Bacillus Thuringiensis; C027132:1-anilino-8-naphthalenesulfonate