Mechanisms of TonB-Dependent Protein Import in Pseudomonas aeruginosa

Lead Research Organisation: University of Oxford
Department Name: Medical Sciences DTC


S-type pyocins are a family of soluble protein antibiotics that are specific for strains of P. aeruginosa. For these proteins to elicit their cytotoxic activity, they must first translocate across the bacterial outer membrane. This process is facilitated by parasitising the Ton system, a bacterial nutrient transport system; comprised of an inner membrane energy-transducing complex and a ligand-specific outer membrane transporter. The mechanism by which pyocin binding to the outer membrane transporter triggers the recruitment of the Ton complex and subsequent protein translocation across the outer membrane is poorly understood. I aim to decipher the molecular and mechanical basis of pyocin translocation by the Ton complex. I will use biochemical and structural techniques to characterise the protein-protein interactions between pyocins with their outer membrane receptors and the Ton complex. I will also design an assay to study the mechanical forces generated by the Ton complex as pyocins are translocated through the outer membrane in vivo, using fluorescence microscopy and force spectroscopy. These studies will determine the mechanism by which P. aeruginosa translocate molecules across the outer membrane; a process of paramount importance for the development of novel antibiotic therapies to target the growing problem of bacterial antibiotic resistance.


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
MR/N013468/1 01/10/2016 30/09/2025
1797450 Studentship MR/N013468/1 01/10/2016 31/03/2021 Jonathan Goult
Description Molecular dynamics simulations - Leeds 
Organisation University of Leeds
Country United Kingdom 
Sector Academic/University 
PI Contribution Our collaborator Prof Emanuele Paci, in conjunction with a PhD student (Daniel Van), have conducted extensive MD simulations helping us to understand how pyocin S2 opens its transporter protein FpvAI. We have tested the outputs of these simulations using various protein engineering strategies. This work has been written up but has yet to be submitted due to delays from the pandemic-principally our collaborator has been trapped in the Netherlands for many months unable to travel back to the UK.
Collaborator Contribution Extensive computer simulations
Impact Work yet to be submitted
Start Year 2018
Description Pseudomonas strain library cytotoxicity screening - University of Glasgow 
Organisation University of Glasgow
Department Institute of Infection, Immunity and Inflammation
Country United Kingdom 
Sector Academic/University 
PI Contribution Expression and purification of pyocins for in vivo screening
Collaborator Contribution Screening of pyocins against a pathogenic P. aeruginosa strain library to determine MICs and therapeutic efficacy in Galleria mellonella infection model
Impact Pathogenic P. aeruginosa strain coverage of PyoSN determined alone and in combination with other pyocin cocktails
Start Year 2020