Negative regulation of bleomycins biosynthesis by ArsR/SmtB family repressor BlmR in Streptomyces verticillus.

Negative regulation of bleomycins biosynthesis by ArsR/SmtB family repressor BlmR in Streptomyces verticillus. Appl Microbiol Biotechnol. 2019 Jun 11;: Authors: Chen H, Wang J, Cui J, Wang C, Liang S, Liu H, Wen J Abstract Bleomycin, a broad-spectrum antibiotic, has been widely used for various tumor treatments. However, its poor fermentation yield is not satisfactory for industrial production. Here, the ArsR/SmtB family regulator BlmR was characterized as a repressor of bleomycin production. As an autoregulator, BlmR was found to bind to a 12-2-12 imperfect palindrome sequence in its own promoter, and deletion of blmR led to a 34% increase of bleomycin B2 production compared with the wild-type strain. Using reverse transcription and quantitative PCR (RT-qPCR), blmT, which encoded a putative transporter, was identified as the target gene regulated by BlmR. Therefore, high-production strain was constructed by blmT overexpression in a blmR deletion strain, and the bleomycin B2 titer reached to 80 mg/L, which was 1.9-fold higher than the wild-type strain. Moreover, electrophoretic mobility shift assay (EMSA) showed neither metal-binding motifs nor redox switches in BlmR. In order to elucidate the regulatory mechanism, a model of BlmR was constructed by homology modeling and protein-protein docking. The BlmR-DNA complex was generated by protein-DNA docking with the assistance of site-directed mutagenesis and molecular dynamic (MD) simula...
Source: Applied Microbiology and Biotechnology - Category: Microbiology Authors: Tags: Appl Microbiol Biotechnol Source Type: research