Beware of proteins bearing gifts: Protein antibiotics that use iron as a Trojan horse

Rhys Grinter, Joel J. Milner, Daniel Walker

Research output: Contribution to journalArticleResearchpeer-review

14 Citations (Scopus)


Multicellular organisms limit the availability of free iron to prevent the utilization of this essential nutrient by microbial pathogens. As such, bacterial pathogens possess a variety of mechanisms for obtaining iron from their hosts, including a number of examples of vertebrate pathogens that obtain iron directly from host proteins. Recently, two novel members of the colicin M bacteriocin family were discovered in Pectobacterium that suggest that this phytopathogen possesses such a system. These bacteriocins (pectocin M1 and M2) consist of a cytotoxic domain homologous to that of colicin M fused to a horizontally acquired plant-like ferredoxin. This ferredoxin domain substitutes the portion of colicin M required for receptor binding and translocation, presumably fulfilling this role by parasitizing an existing ferredoxin-based iron acquisition pathway. The ability of susceptible strains of Pectobacterium to utilize plant ferredoxin as an iron source was also demonstrated, providing additional evidence for the existence of such a system. If this hypothesis is correct, it represents the first example of iron piracy directly from a host protein by a phytopathogen and serves as a testament of the flexibility of evolution in creating new bacteriocin specificities.

Original languageEnglish
Number of pages9
JournalFEMS Microbiology Letters
Issue number1
Publication statusPublished - Jan 2013
Externally publishedYes


  • Bacteriocin
  • Iron
  • Pectobacterium
  • Pectocin
  • Siderophore
  • Soft rot

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