SUMMARY. Strain Streptomyces albus J1074 remains one of the most important platforms for natural product discovery via the expression of biosynthetic gene clusters (BGCs) from the microorganisms of Actinobacteria class. Numerous approaches of maximizing the expression of heterologous BGCs in this strain have been described, yet there are no reports on the properties of spontaneous J1074 mutants in gene rpsL for ribosomal protein S12. The interest in such mutations in actinobacteria is caused by the fact that they induce a considerable increase in the antibiotic activity. In this work we describe the isolation and characterization of strain S. albus KO-1297 carrying missense mutation within rpsL gene, which leads to substitution Lys88àGlu in protein S12. As compared to the parental strain, this mutant exhibits increased resistance to streptomycin and enhanced antibiotic productivity. КО-1297 and engineered rpsLK88E strain К88Е are not identical in their ability to produce antibiotics. КО-1297 also exhibits a certain level of instability of rpsL mutation. Genomes of КО-1297 and its rpsLWT revertant harbor the mutations that could be responsible for phenotypic differences between these strains, parental strain and К88Е.
Keywords: Streptomyces albus J1074, rpsL мутації, геноміка