Identification of a diphtheria toxin‐like gene family beyond the Corynebacterium genus Academic Article uri icon

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  • Diphtheria toxin (DT), produced by Corynebacterium diphtheria, is the causative agent of diphtheria and one of the most potent protein toxins known; however, it has an unclear evolutionary history. Here, we report the discovery of a DT-like gene family in several bacterial lineages outside of Corynebacterium, including Austwickia and Streptomyces. These DT-like genes form sister lineages in the DT phylogeny and conserve key DT features including catalytic and translocation motifs, but possess divergent receptor-binding domains. DT-like genes are not associated with corynephage, but have undergone lateral transfer through a separate mechanism. The discovery of the first non-Corynebacterium homologs of DT sheds light on its evolutionary origin and highlights novelties that may have resulted in the emergence of DT targeting humans.


  • Mansfield, Michael J
  • Sugiman‐Marangos, Seiji N
  • Melnyk, Roman A
  • Doxey, Andrew

publication date

  • August 2018

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