LAUSR

We describe Streptomyces fradiae mechanisms of sensitivity to nitrone‐oligomycin A, a derivative of oligomycin A. We obtained S. fradiae‐nitR+bld, a nitrone‐oligomycin A resistant mutant with a «bald» phenotype. Comparative genomic analysis of the wild‐type S. fradiae ATCC19609 and S. fradiae‐nitR+bld revealed a mutation in padR – a gene encoding a multifunction transcription regulator, which resulted in the amino acid replacement in a highly conserved DNA‐binding domain. Bioinformatics genome analysis of S. fradiae ATCC19609 discovered a PadR binding site 13 bp upstream the start codon of the marR transcription factor gene. Induction of S. fradiaenitR+bld and w.t. strains with nitrone‐oligomycin A lead to a significant increase in expression level of the marR gene in the w.t. strain, but no change observed in mutant strain. We identified differences between DNA–protein interactions of the mutant and native PadR proteins with its putative binding site in S. fradiae ATCC19609. This allowed us to suggest that the padR gene, that harbored a single nucleotide mutation in the S. fradiaenitR+bld strain, might be involved in the mechanism of resistance to nitrone‐oligomycin A. We assume the participation of the transcriptional factorpadR in the formation of the bald phenotype.