Ion channels formed in planar lipid bilayers by Bacillus thuringiensis toxins in the presence of Manduca sexta midgut receptors.
A purified, GPI-linked receptor complex isolated from Manduca sexta midgut epithelial cells was reconstituted in planar lipid bilayers. CryIAa, CryIAc and CryIC, three Bacillus thuringiensis insecticidal proteins, formed channels at much lower doses (0.33-1.7 nM) than in receptor-free membranes. The non-toxic protein CryIB also formed channels, but at doses exceeding 80 nM. The channels of CrylAc, the most potent toxin against M. sexta, rectified the passage of cations. All other toxin channels displayed linear current-voltage relationships. Therefore, reconstituted Cry receptors catalyzed channel formation in phospholipid membranes and, in two cases, were involved in altering their biophysical properties.
Schwartz
J L
JL
Biotechnology Research Institute, National Research Council, Montreal, Que., Canada. jean-louis.schwartz@bri.nrc.ca
Lu
Y J
YJ
Söhnlein
P
P
Brousseau
R
R
Laprade
R
R
Masson
L
L
Adang
M J
MJ
D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000494:pharmacology*; D001427:Bacterial Toxins; D018826:CD13 Antigens / Q000378:metabolism; D004064:Digestive System / Q000201:enzymology / Q000378:metabolism; D004731:Endotoxins / Q000494:pharmacology*; D006460:Hemolysin Proteins; D007473:Ion Channels / Q000096:biosynthesis* / Q000378:metabolism; D008051:Lipid Bilayers / Q000378:metabolism*; D018402:Manduca / Q000378:metabolism*
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D018826:CD13 Antigens