Genes of Streptomyces globisporus 1912-4Crt Encoding Chitin Catabolism Enzymes

Polysaccharide chitin is one of the most common biopolymers in nature. Chitin (when used as the sole source of energy, carbon, and nitrogen) has been shown to be a substrate sufficient to enable the growth and synthesis of secondary metabolites by the S. griseus NCIMB 8136 strain and some other streptomycetes. The species Streptomyces globisporus and S. griseus belong to the same lower hierarchical taxon (S. griseus clade). The aim was to find in the S. globisporus 1912-4Crt genome genes encoding proteins that are necessary for chitin fermentation and transmembrane transport of resulting products. Methods. The object of the study was a sequence of the S. globisporus 1912-4Crt genome (reference NZ_QWFA01000000.1, GenBank) on the server of NCBI (The National Center for Biotechnology Information). Streptomycete S. globisporus 1912 and its variants are producers of antibiotic landomycin E and carotenoids. Search for and analysis of nucleotide and amino acid sequences were performed using programs BLAST (Basic Local Alignment Search Tool) on the aforementioned server. Results. A set of genes that determine enzymes of chitin catabolism and Ngc-transporter proteins were identified in the S. globisporus 1912-4Crt genome. Genes encoding 10 endo-acting chitinases (from the GH18 and GH19 families) and 2 exo-acting hydrolases (GH20) were identified in the S. globisporus 1912-4Crt sequence. Several genes determining deacetylases that deacetylate both chitin and oligosaccharides were found in the genome of the strain. One gene that determines endo-acting chitosanase from the GH75 family was discovered there. The ability of the wild-type strain S. globisporus 1912 and a number of its variants (including S. globisporus 1912-4Crt) to ferment chitin was proven in vitro. Conclusions. A set of genes sufficient for chitin assimilation was established in the S. globisporus 1912-4Crt genome sequence. Streptomycetes from different clades (for example, strains of S. coelicolor (S. albidoflavus group) and S. griseus, S. globisporus (S. griseus group)) containing different complexes of chitinolytic enzymes could be suggested.