PURIFICATION AND PARTIAL AMINO-ACID-SEQUENCES OF THE BINDING-PROTEIN FROM BOMBYX-MORI FOR CRYIAA DELTA-ENDOTOXIN OF BACILLUS-THURINGIENSIS

The binding protein for Bacillus thuringiensis delta-endotoxin, CryIAa , from the brush border membrane of the midgut of Bombyx mori was puri fied by the dot blot method and delta-endotoxin affinity chromatograph y. The binding protein was purified to 235-fold enrichment from cholic acid extracts of brush border membranes from B. mori midgut by activa ted CryIAa-affinity chromatography and DEAE ion-exchange chromatograph y. The purified binding protein showed a single band of 180 kDa by sod ium dodecyl sulfate polyacrylamide gel electrophoresis and this band s pecifically reacted to I-125-labeled CryIAa on Immobilon membrane. The affinity of the binding protein. for CryIAa was equivalent to that of the brush border membrane vesicles and solubilized membrane proteins. Partial amino acid sequences of the binding protein showed sequence s imilarity to the cadherin-like binding protein for CryIAb from Manduca sexta, but not for CryIAc binding protein from M. sexta and Heliothis virescens. (C) 1998 Elsevier Science Inc. All rights reserved.