A54145, a new lipopeptide antibiotic complex: factor control through precursor directed biosynthesis

Area of Science:

• Microbiology
• Biochemistry
• Synthetic Biology

Background:

• A54145 is a lipopeptide antibiotic complex produced by Streptomyces fradiae.
• Eight distinct factors with variations in peptide nuclei and fatty acid side chains were identified.

Purpose of the Study:

• To investigate the effect of fatty acid precursors on the native biosynthesis of A54145 factors by S. fradiae.
• To induce the production of preferred antibiotic factors or analogs through precursor feeding.

Main Methods:

• Fermentation of S. fradiae with controlled addition of fatty acid precursors.
• Utilized stirred bioreactors with on-line respiration analysis via mass spectrometry due to precursor toxicity.
• Supplementation of media with specific amino acids (valine or isoleucine) in shaken-flask studies.

Main Results:

• Fatty acid precursors significantly enhanced the biosynthesis of factors with specific fatty acid acyl side chains.
• Caprate feeding increased n-decanoyl-containing factors from ~14% to ~80%.
• Enriching the medium with valine or isoleucine increased factors with branched-chain fatty acid substituents and specific amino acid incorporation into peptide nuclei.

Conclusions:

• Controlled precursor feeding is an effective strategy to modulate lipopeptide antibiotic biosynthesis.
• This method allows for the targeted enhancement of specific antibiotic factors with desired structural features.
• The findings provide a basis for optimizing the production of A54145 analogs for potential therapeutic applications.