Journal Article

Metabolic perturbation to enhance polyketide and nonribosomal peptide antibiotic production using triclosan and ribosome-targeting drugs

Hiraga, Yoshikazu, Izawa, Masumi, Tanaka, Yukinori, Misaki, Yuya, Watanabe, Tomoko, Ochi, Kozo

2017

Overview

Although transcriptional activation of pathwayspecific positive regulatory genes and/or biosynthetic genes is primarily important for enhancing secondary metabolite production, reinforcement of substrate supply, as represented by primary metabolites, is also effective. For example, partial inhibition of fatty acid synthesis with ARC2 (an analog of triclosan) was found to enhance polyketide antibiotic production. Here, we demonstrate that this approach is effective even for industrial high-producing strains, for example enhancing salinomycin production by 40%, reaching 30.4 g/l of salinomycin in an industrial Streptomyces albus strain. We also hypothesized that a similar approach would be applicable to another important antibiotic group, nonribosomal peptide (NRP) antibiotics. We therefore attempted to partially inhibit protein synthesis by using ribosome-targeting drugs at subinhibitory concentrations (1/50∼1/2 of MICs), which may result in the preferential recruitment of intracellular amino acids to the biosynthesis of NRP antibiotics rather than to protein synthesis. Among the ribosome-targeting drugs examined, chloramphenicol at subinhibitory concentrations was most effective at enhancing the production by Streptomyces of NRP antibiotics such as actinomycin, calcium-dependent antibiotic (CDA), and piperidamycin, often resulting in an almost 2-fold increase in antibiotic production. Chloramphenicol activated biosynthetic genes at the transcriptional level and increased amino acid pool sizes 1.5- to 6-fold, enhancing the production of actinomycin and CDA. This “metabolic perturbation” approach using subinhibitory concentrations of ribosome-targeting drugs is a rational method of enhancing NRP antibiotic production, being especially effective in transcriptionally activated (e.g., rpoB mutant) strains. Because this approach does not require prior genetic information, it may be widely applicable for enhancing bacterial production of NRP antibiotics and bioactive peptides.

• Publisher: Springer Berlin Heidelberg,Springer,Springer Nature B.V
• Subject: Actinomycin / Amino acids / Analysis / Anti-Bacterial Agents - biosynthesis / Antibacterial agents / Antibiotics / Bacterial Proteins - genetics / Bacterial Proteins - metabolism / Biomedical and Life Sciences / Biosynthesis / Biotechnological Products and Process Engineering / Biotechnology / Calcium / Chloramphenicol / Chloramphenicol - pharmacology / Chloromycetin / Drug delivery / Drugs / Fatty acid synthesis / Fatty acids / Gene Expression Regulation, Bacterial / Genes / Industrial Microbiology - methods / Life Sciences / Lincomycin - pharmacology / Metabolism / Metabolites / Microbial Genetics and Genomics / Microbial Sensitivity Tests / Microbiology / mutants / Peptide Biosynthesis, Nucleic Acid-Independent / Peptides / Peptides - chemistry / Perturbation / Plant metabolites / polyketides / Polyketides - metabolism / Production processes / Protein biosynthesis / Protein synthesis / Proteins / Pyrans - metabolism / regulator genes / Reinforcement / Ribonucleic acid / Ribosomes - drug effects / Ribosomes - metabolism / RNA / RpoB protein / Salinomycin / secondary metabolites / Strains (organisms) / Streptomyces - drug effects / Streptomyces - genetics / Streptomyces - metabolism / Streptomyces albus / Substrate inhibition / Transcription (Genetics) / Transcription activation / transcriptional activation / Triclosan / Triclosan - pharmacology