Coordinative Modulation of Chlorothricin Biosynthesis by Binding of the Glycosylated Intermediates and End Product to A Responsive Regulator ChlF1 [Gene Regulation]

January 10th, 2016 by Li, Y., Li, J., Tian, Z., Xu, Y., Zhang, J., Liu, W., Tan, H.

Chlorothricin, isolated from Streptomyces antibioticus, is a parent member of spirotetronate family of antibiotics that have long been appreciated for their remarkable biological activities. ChlF1 plays bifunctional roles in chlorothricin biosynthesis by binding to its target genes (chlJ, chlF1, chlG and chlK). The dissociation constants of ChlF1 to these genes are around 102-140 nM. A consensus sequence, 5′-GTAANNATTTAC-3′, was found in these binding sites. ChlF1 represses the transcription of chlF1, chlG and chlK but activates chlJ, which encodes a key enzyme acyl-CoA carboxyl transferase involved in the chlorothricin biosynthesis. We demonstrate that the end product chlorothricin and likewise its biosynthetic intermediates (demethylsalicycloyl chlorothricin and deschloro-chlorothricin) can act as signaling molecules to modulate the binding of ChlF1 to its target genes. Intriguingly, a correlation between the antibacterial activity and binding ability of signaling molecules to the regulator ChlF1 is clearly observed. These features of the signaling molecules are associated with the glycosylation of spirotetronate macrolide aglycone. The findings provide new insights into the TetR family regulators responding to special structure of signaling molecules, and we reveal the regulatory mini-network mediated by ChlF1 in chlorothricin biosynthesis for the first time.
  • Posted in Journal of Biological Chemistry, Publications
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