Binding assay between Cry9Aa and Vip3Aa toxins.
A, ligand-blot binding assays of 5 nm biotinylated Vip3Aa or Cry9Aa toxins bound to Cry9Aa or Vip3Aa blotted on the PVDF membrane (0.5 μg of each protein), showing that they can interact with each other. B, ELISA binding of increasing concentrations of biotinylated Cry9Aa to 1 μg of Vip3Aa protein bound to the ELISA plate, showing saturable binding. Error bars represent S.D. C, SPR binding analyses of Vip3Aa were performed by immobilizing Vip3Aa toxin by conventional amine coupling. Sensorgrams of serial doubling dilutions of Cry9Aa are shown. D, competition ELISA binding assay of 28 nm biotinylated Vip3Aa to 0.5 μg of Cry9Aa protein bound to the ELISA plate performed in the presence of different excesses of unlabeled Vip3Aa as competitor, showing that their interaction is specific. Error bars represent S.D. Abs, absorbance.