Cloning and sequence analysis of the gene encoding a thermostable chitinase from Streptomyces thermoviolaceus OPC-520

The gene ( chi40 ) encoding a thermostable chitinase from Streptomyces thermoviolaceus OPC-520 was cloned in Escherichia coli JM109 using pUC18. The nucleotide (nt) sequence of chi40 has been determined. A single open reading frame (ORF) encoded a protein consisting of 414 amino acids (aa) with a M r of 43 838. The deduced aa sequence of the cloned chitinase (Chi40) showed striking homology (74%) with Chi63 from Streptomyces plicatus . Comparison with other chitinases revealed that Chi40 contained the two conserved regions common to microbial and plant chitinases. Furthermore, the putative promoter region of chi40 , which might be involved in the repression and induction of such catabolite-controlled genes, was detected by the DNA sequence alignments.