Abstract:Based on the conserved 5' and 3' sequence of chitinase gene from B.thuringiensis, a product of 2031 bp was amplified and cloned into Escherichia coli strain DH5α from B.thuringiensis serovar entomocidus strain HD109 genomic DNA. The product encoded an open reading frame (chiA74-HD109) encoding a deduced protein of 676 amino acids. Removal of the signal peptide sequence resulted in a predicted protein that was 70457 Da in size and 5.45 of isoelectric point. The deduced 676 amino acids sequence showed high degree of identity with other chitinases such as ChiB (AB041932) from Bacillus cereus (97.9%), chiA74 (AF424979) from B.thuringiensis serovar kenyae strain LBIT-82 (98.4%), chitinase (U89796) from B.thuringiensis serovar pakistani (83.0%), kchi (AY189740) from B.thuringiensis serovar kurstaki (97.8%), chitinase (AF526379) from B.thuringiensis serovar israelensis (96.6%), chitinase (AY074882) from B.thuringiensis (98.4%), and chitinase (AY129671) from B.thuringiensis serovar sotto (97.3%).Analysis of the sequence indicated that the chitinase contained a catalytic domain belonging to family 18 of glycosyl hydrolases in the N-terminus, a fibronectin type Ⅲ domain in the middle region and a chitin-binding domain in the C-terminus.All three domains showed conserved sequences when compared to other bacterial chitinase sequences.