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ß-Glucosidase enzymatic activity of crystal polypeptide of the Bacillus thuringiensis strain 1.1Laboratory of General Microbiology, Section of Genetics, Development and Molecular Biology, School of Biology, Aristotle University, Thessaloniki, Greece
Laboratory of General Microbiology, Section of Genetics, Development and Molecular Biology, School of Biology, Aristotle University, Thessaloniki, Greece
Laboratory of General Microbiology, Section of Genetics, Development and Molecular Biology, School of Biology, Aristotle University, Thessaloniki, Greece, asivropo{at}bio.auth.gr
The crystals of Bacillus thuringiensis strain 1.1 consist of the 140 kDa
Journal of Endotoxin Research, Vol. 9, No. 4,
215-224 (2003) |
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-endotoxin, which exhibits ß-glucosidase enzymatic activity, based on the following data. (i) Purified crystals exhibit ß-glucosidase enzymatic activity. When the crystals are reacted with specific antibodies directed either against the commercial (almond purified) ß-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 ß-glucosidase and the 140 kDa crystal polypeptide share antigenic similarities; in Western immunoblots, the 140 kDa crystal polypeptide is recognized by anti-ß -glucosidase antibodies, and commercial ß-glucosidase is recognized by anti-140-kDa antibodies. (iii) The enzymatic properties of commercial ß-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-ß -glucosides, disaccharides with 
- or ß-linkage polysaccharides) and have an optimum activity at 40°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 ß-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.