Toxin proteins are genetically engineered into our food because they kill insects by perforating body cell walls, and Professor Rikard Blunck of the University of Montreal’s Group for the study of membrane proteins (GÉPROM) has detected the molecular mechanism involved.
The Cry1Aa toxin of B. thuringiensis that was investigated is a member of the class of proteins which are called “pore-forming toxins” because they perforate the walls, or membranes, of cells. Cry toxins kill insect larvae if ingested by them and are, therefore, genetically engineered into a number of transgenic crops, including those for human consumption, to make them resistant against these insects.
“By watching the toxin in both its active and inactive state, and by measuring the dynamic changes of the light emitted by the molecular probes, we were able to determine which parts of it were interacting with the membrane to cause the pores.” Dr. Blunck explained. “We expect the technique to be applied to a wide range of disease-causing toxins in future.”