Crystal Proteins from B. thuringiensis

The significance of cadherin-like proteins as receptors has been demonstrated by ectopic expression in different cell lines [12, 13] and is further corroborated by the presence of mutated cadherin genes in resistant Hdiothis virescens [14, 15] and Pectinophora gossypidla [16, 17] insect strains. In addition, glycolipids and glycosylated alkaline phosphatase have been implicated in Cry binding [18, 19]. 

More than 300 Cry sequences are currently known and classified solely on the basis of sequence homology of the full-length proteins into 49 Cry classes [20, 

the crystal structure of six activated Cry proteins has been solved [22-27]. These proteins, CrylAa, CrylAc, Cry2Aa, Cry3Aa, Cry3Bb, and Cry4Ba, have a very similar architecture and are composed of three structural domains. The N-terminal domain [residues 58-290 (in Cry3A)] contains seven a-helices with the central more hydrophobic helix ( 5) encirded by she outer amphipathic helices. 

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