Polysaccharide agarose is a component of the cell walls of red algae. The ability of streptomycetes to ferment agarose was first discovered in the Streptomyces coelicolor A3(2) strain. The way of polysaccharide assimilation by the S. coelicolor A3(2) strain and the genes that determine the proteins necessary for this have been established. These genes are collected in a cluster and localized on the S. coelicolor A3(2) chromosome. The aim of the work was to identify streptomycetes whose genomes contain sequences similar to the agarolytic cluster of S. coelicolor A3(2), to establish the genetic relationship of the identified streptomycetes, and also to study the similarities and differences of the amino acid sequences of streptomycetes that are similar to the DagR repressor. Information in databases on the NCBI server («The National Center for Biotechnology Information») was analysed. The bioinformative research method was used using BLAST programs on the NCBI server. Nucleotide sequences of the agarolytic cluster and 16S rRNA of the S. coelicolor A3(2) strain were used as queries in BLASTN analysis. The amino acid sequence of the DagR transcription regulator of the S. coelicolor A3(2) strain was used as a query in BLASTP analysis. It was established that probable agarolytic clusters are present in the genomes of 19 streptomycetes belonging to species of different taxonomic clades (S. rochei, S. violaceoruber, S. griseoincarnatus). It was shown that there are no substitutions of amino acid residues in the primary structures of probable transcription regulators in positions important for functioning.
Keywords: streptomycete, agarolytic cluster, genetic relatedness, sequence similarity indicators, regulator
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