NUCLEOTIDE-SEQUENCE AND ANALYSIS OF A GENE (CHIA) FOR A CHITINASE FROM STREPTOMYCES-LIVIDANS-66

A chitinase gene (chiA) from Streptomyces lividans was characterized and its nucleotides sequenced. Although the deduced amino acid sequence of chitinase A1 did not show any similarity to those of other Streptomyces chitinases that has been sequenced, the C-terminal part, containing both a putative catalytic domain and type-III-like repeating units, showed a similarity (36%) to that of chitinase D from Bacillus circulans. A site of initiation of transcription was found approximately 51 bp upstream from the GTG initiation codon. The promoter region of the chiA gene was subcloned on a 178-bp fragment into the promoter-probe vector pIJ486, resulting in the chitin stimulated expression of the neomycin resistance gene. One of the deleted subclones, which contained a 114-bp sequence upstream from the translation start codon, retained both chitin stimulated production and glucose repression. Chitin stimulated production was lost in an other deleted mutant containing the 104-bp upstream sequence.