High-multiplicity of chitinase genes in Streptomyces coelicolor A3(2)

Six different genes for chitinase from ordered cosmids of the chromosome of Streptomyces coelicolor A3(2) were identified by hybridization, using the chitinase genes from other Streptomyces spp. as probes, and cloned. The gen es were sequenced and analyzed. The genes, together with an additional chit inase gene obtained from the data bank, can be classified into either famil y 18 or family 19 of the glycosyl hydrolase classification. The five chitin ases that fall into family 18 show diversity in their multiple domain struc tures as well as in the amino acid sequences of their catalytic domains. Th e remaining two chitinases are members of family 19 chitinases, since their C-terminus shares more than 70% identity with the catalytic domain of ChiC of Streptomyces griseus, the sole gene for family 19 chitinase so far foun d in an organism other than higher plants.