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 maize by Monsanto, Northrup King and Ciba Geigy. Toxic segment of the protein is located in the N-terminus. In strain S93 this is encoded on plasmid pUCBtS39. Belongs to the delta endotoxin family.