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Cry11Aa toxin from Bacillus thuringiensis binds its receptor in Aedes aegypti mosquito larvae through loop α‐8 of domain II
Author(s) -
Fernández Luisa E.,
Pérez Claudia,
Segovia Lorenzo,
Rodríguez Mario H.,
Gill Sarjeet S.,
Bravo Alejandra,
Soberón Mario
Publication year - 2005
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2005.05.032
Subject(s) - bacillus thuringiensis , aedes aegypti , mutagenesis , biology , mutant , midgut , receptor , toxin , microbiology and biotechnology , biochemistry , bacteria , larva , gene , genetics , botany
Bacillus thuringiensis subs israelensis produces Cry toxins active against mosquitoes. Receptor binding is a key determinant for specificity of Cry toxins composed of three domains. We found that exposed loop α‐8 of Cry11Aa toxin, located in domain II, is an important epitope involved in receptor interaction. Synthetic peptides corresponding to exposed regions in domain II (loop α‐8, β‐4 and loop 3) competed binding of Cry11Aa to membrane vesicles from Aedes aegypti midgut microvilli. The role of loop α‐8 of Cry11A in receptor interaction was demonstrated by phage display and site‐directed mutagenesis. We isolated a peptide‐displaying phage (P5.tox), that recognizes loop α‐8 in Cry11Aa, interferes interaction with the midgut receptor and attenuates toxicity in bioassay. Loop α‐8 mutants affected in toxicity and receptor binding were characterized.