The role of DNA binding with the Cry8Ea1 toxin of Bacillus thuringiensis

The Cry8Ea1 protoxin is a DNA-protein complex. Both forms of the Cry8Ea1 toxin (with or without DNA binding) were obtained separately, and their stability and ability to insert into a phospholipid monolayer in vitro were compared. The presence of DNA can prevent the toxin from aggregation. Data regarding the penetration of the Cry8Ea1 toxin and Cry8Ea1 toxin-DNA complex into the air/water interface without a phospholipid monolayer show that the Cry8Ea1 toxin-DNA complex is more likely to move towards the air/water interface and is more hydrophobic. Experiments examining the protein interaction with the phospholipid monolayer show that the ability of the Cry8Ea1 toxin-DNA complex to insert into the lipid bilayer is much greater than that of the Cry8Ea1 toxin without DNA.