Promotes colloidosmotic lysis by binding to the midgut epithelial cells of many lepidopteran larvae. The crystal protein is produced during sporulation and is accumulated both as an inclusion and as part of the spore coat. Introduced by genetic manipulation and expressed in insect-resistant cotton and tomato by Calgene (Monsanto) and in maize by Dekalb Genetics. Toxic segment of the protein is located in the N-terminus. Belongs to the delta endotoxin family.