Outer membrane translocation of pyocins via the copper regulated TonB-dependent transporter CrtA

Jiraphan Premsuriya, Khedidja Mosbahi, Iva Atanaskovic, Colin Kleanthous, Daniel Walker

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
17 Downloads (Pure)


Pseudomonas aeruginosa is a common cause of serious hospital-acquired infections, the leading proven cause of mortality in people with cystic fibrosis and is associated with high levels of antimicrobial resistance. Pyocins are narrow-spectrum protein antibiotics produced by P. aeruginosa that kill strains of the same species and have the potential to be developed as therapeutics targeting multi-drug resistant isolates. We have identified two novel pyocins designated SX1 and SX2. Pyocin SX1 is a metal-dependent DNase while pyocin SX2 kills cells through inhibition of protein synthesis. Mapping the uptake pathways of SX1 and SX2 shows these pyocins utilize a combination of the common polysaccharide antigen (CPA) and a previously uncharacterized TonB-dependent transporter (TBDT) PA0434 to traverse the outer membrane. In addition, TonB1 and FtsH are required by both pyocins to energize their transport into cells and catalyze their translocation across the inner membrane, respectively. Expression of PA0434 was found to be specifically regulated by copper availability and we have designated PA0434 as Copper Responsive Transporter A, or CrtA. To our knowledge these are the first S-type pyocins described that utilize a TBDT that is not involved in iron uptake.
Original languageEnglish
Pages (from-to)1035-1049
Number of pages15
JournalBiochemical Journal
Issue number14
Early online date3 Jul 2023
Publication statusPublished - 17 Jul 2023


  • cell biology
  • molecular biology
  • biochemistry
  • antibiotic resistance
  • pseudomonas aeruginosa
  • bacteriocin
  • pyocin
  • molecular interactions
  • structural biology


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