A high homology exists in N-terminal amino acid sequences of delta-endotoxins between Lepidoptera-specific and Coleoptera-specific Bacillus thuringiensis strains.

The 130 kDa parasporal inclusion proteins of the Lepidoptera-specific Bacillus thuringiensis reference strains for four H serovars were examined for sequences of 14 N-terminal amino acids. The four sequences fell into a single category, MNRNNQNEYEVIDA, and were dissimilar to any of the established sequences for Lepidoptera- and/or Diptera-killing crystal proteins. They were highly related to the reported sequence of the 130 kDa protein of the strain Buibui (serovar japonensis), which is specific for scarabaeid coleopterans.