Open AccessAminopeptidase N from Bombyx Mori as a Candidate for the Receptor of Bacillus Thuringiensis Cry1Aa Toxin
Author(s) -
Yaoi Katsuro,
Kadotani Tomoyuki,
Kuwana Hisanaga,
Shinkawa Ayaka,
Takahashi Tsuyoshi,
Iwahana Hidenori,
Sato Ryoichi
Publication year - 1997
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1997.t01-1-00652.x
Subject(s) - biochemistry , toxin , biology , aminopeptidase , bacillus thuringiensis , midgut , bombyx mori , microbiology and biotechnology , amino acid , bacteria , leucine , genetics , botany , larva , gene
Cry1Aa toxin‐binding proteins from the midgut brush border membrane vesicles of Bombyx mori , a toxin‐susceptible silkworm, were analyzed to find candidates for the toxin receptors. Ligand blotting showed that Cry1Aa toxin bound to a 120‐kDa protein. A part of the 120‐kDa protein was solubilized from the membrane vesicles with phosphatidylinositol‐specific phospholipase C, resulting in a 110‐kDa protein which therefore may be linked to a glycosylphosphatidylinositol anchor. The 120‐kDa and 110‐kDa Cry1Aa toxin‐binding proteins were solubilized with detergent or pohosphatidylinositol‐specific phospholipase C, respectively, and purified using anion‐exchange chromatography. Scatchard plot analysis for the specific binding of purified 110‐kDa protein to Cry1Aa toxin yielded a K d value of 7.6 nM, which was similar to that for the binding of intact brush border membrane vesicles to the toxin. N‐terminal and internal amino acid sequences of the 120‐kDa and 110‐kDa proteins showed high degrees of similarity to those of aminopeptidase N, a putative Cry1Ac toxin receptor, reported in Manduca sexta and Heliothis virescens . On this basis, the 120‐kDa Cry1Aa toxin‐binding protein from B. mori was identified as a member of the aminopeptidase family.