Active enhancement of bacillus thuringiensis subspisraelensis toxins and protein-purification

ABSTRACT

Bacillus thuringiensissub sp. ilsraelensis de Barjac, that produce insecticidal protein endotoxins are used for mosquito control. The bacterium produces several cry and cytoxins that individually show activity against mosquitoes. A CryllA protein IA848, which corresponds to the first 848 amino acids from N-terminal of CryllA-gene was purified from E.coli by Ni-NTA affinity isolation, Q-Sepharose Fast-Flow chromatography and Super-200 size exclusion chromatography. It was determined using laboratory bioassays that the purified-IA848 protein has good insecticidal competitive binding bioassays show that IA848 does not compete with CryIAb for binding to the brush border membrane vesicles [BBM] of the Aedesaegyptiborer and does not compete with CryIAb at concentrations below 400-fold excess of un-labeled CrylAb for binding to the peritrophic matrix [PM] of the insect. This IA848 proved good competitive in control strategies. CryllA protein purification demonstrate molecular mechanism by which CytIA synergizes or suppresses resistance to toxins by providing a binding site for CryIIAa that resulted in an efficient formation of CryIIAa pre-pore that inserts into membranes and forms'fonic pores