The Vip3Ag4 Insecticidal Protoxin from Bacillus thuringiensis Adopts A Tetrameric Configuration That Is Maintained on Proteolysis.

ABSTRACT: The Vip3 proteins produced during vegetative growth by strains of the bacterium Bacillus thuringiensis show insecticidal activity against lepidopteran insects with a mechanism of action that may involve pore formation and apoptosis. These proteins are promising supplements to our arsenal of insecticidal proteins, but the molecular details of their activity are not understood. As a first step in the structural characterisation of these proteins, we have analysed their secondary structure and resolved the surface topology of a tetrameric complex of the Vip3Ag4 protein by transmission electron microscopy. Sites sensitive to proteolysis by trypsin are identified and the trypsin-cleaved protein appears to retain a similar structure as an octomeric complex comprising four copies each of the ~65

SUBMITTER: Palma L 

PROVIDER: S-EPMC5450713 | biostudies-literature | 2017 May

REPOSITORIES: biostudies-literature