Beta-glucosidase enzymatic activity of crystal polypeptide of the Bacillus thuringiensis strain 1.1.
The crystals of Bacillus thuringiensis strain 1.1 consist of the 140 kDa delta-endotoxin, which exhibits beta-glucosidase enzymatic activity, based on the following data. (i) Purified crystals exhibit beta-glucosidase enzymatic activity. When the crystals are reacted with specific antibodies directed either against the commercial (almond purified) beta-glucosidase or against the 140 kDa polypeptide, then considerable reduction of enzymatic activity is observed almost at the same level with both antibodies. (ii) Commercial beta-glucosidase and the 140 kDa crystal polypeptide share antigenic similarities; in Western immunoblots, the 140 kDa crystal polypeptide is recognized by anti-beta-glucosidase antibodies, and commercial beta-glucosidase is recognized by anti-140-kDa antibodies. (iii) The enzymatic properties of commercial beta-glucosidase and that resident in the crystals of B. thuringiensis strain 1.1 are very similar. Thus, both enzymes hydrolyze a wide range of substrates (aryl-beta-glucosides, disaccharides with alpha- or beta-linkage polysaccharides) and have an optimum activity at 40 degrees C and pH 5. Both enzymes are relatively thermostable and are resistant to end-product inhibition by glucose. Additionally, they show the same pattern of inhibition or activation by several chemical compounds. (iv) The crystals and commercial beta-glucosidase show almost equivalent levels of insecticidal activity against Drosophila melanogaster larvae and, furthermore, cause reduction in adult flies that emerge from larvae surviving treatment.
Papalazaridou
A
A
Laboratory of General Microbiology, Section of Genetics, Development and Molecular Biology, School of Biology, Aristotle University, Thessaloniki, Greece.
Charitidou
L
L
Sivropoulou
A
A
D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000201:enzymology*; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D001427:Bacterial Toxins / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D015153:Blotting, Western; D003460:Crystallization; D004331:Drosophila melanogaster; D004591:Electrophoresis, Polyacrylamide Gel; D007306:Insecticides; D007814:Larva / Q000187:drug effects; D008970:Molecular Weight; D001617:beta-Glucosidase / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D007306:Insecticides; D001617:beta-Glucosidase