Membrane binding and oligomer membrane insertion are necessary but insufficient for Bacillus thuringiensis Cyt1Aa toxicity

- Cyt1Aa is properly activated by Manduca sexta midgut proteases.
- Cyt1Aa shows specific binding to Manduca sexta BBMV.
- Manduca sexta midgut proteases facilitates Cyt1Aa oligomer formation in the presence of membrane lipids.
- A similar region containing Cys residue of Cyt1Aa inserts into Manduca sexta and Aedes aegypti midgut membranes.