A Rebeccamycin Analog Provides Plasmid-Encoded Niche Defense

J Am Chem Soc. 2015 Nov 18;137(45):14272-4. doi: 10.1021/jacs.5b09794. Epub 2015 Nov 10.


Bacterial symbionts of fungus-growing ants occupy a highly specialized ecological niche and face the constant existential threat of displacement by another strain of ant-adapted bacteria. As part of a systematic study of the small molecules underlying this fraternal competition, we discovered an analog of the antitumor agent rebeccamycin, a member of the increasingly important indolocarbazole family. While several gene clusters consistent with this molecule's newly reported modification had previously been identified in metagenomic studies, the metabolite itself has been cryptic. The biosynthetic gene cluster for 9-methoxyrebeccamycin is encoded on a plasmid in a manner reminiscent of plasmid-derived peptide antimicrobials that commonly mediate antagonism among closely related Gram-negative bacteria.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actinobacteria / drug effects*
  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology*
  • Carbazoles / chemistry
  • Carbazoles / pharmacology*
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Plasmids / genetics*
  • Plasmids / metabolism


  • Anti-Bacterial Agents
  • Carbazoles
  • rebeccamycin