Prof. Dr. Colin Kleanthous Department of Biochemistry University of Oxford, UK
“Protein import in Gram-negative bacteria”
Unlike their endosymbiont descendants mitochondria and plastids, bacteria do not have dedicated protein import systems. Yet, paradoxically, protein import is implicit to the toxicity mechanisms that underpin bacteriocin-mediated competition between bacteria. Discovered almost a century ago, bacteriocins are species-specific peptide or protein antibiotics deployed by bacteria to kill their neighbours during competition for resources. Bacteriocins contribute to the stable co-existence of bacteria within microbiomes, are exploited by pathogens and commensals alike and have been shown to be effective therapeutics in animal models of infection, suggesting they may have utility as novel antibiotics. Protein bacteriocins are 40-70 kDa toxins that kill susceptible organisms by binding to a specific receptor and translocating a cytotoxic domain (an enzyme or ionophore) through the cell envelope by an unknown mechanism. My talk will focus on recent work where using a combination of crystallography, isothermal titration calorimetry, crosslinking and super-resolution imaging we have uncovered how nuclease bacteriocins specific for Escherichia coli and Pseudomonas aeruginosa translocate across the outer membrane. The work highlights similarities between classical protein import in eukaryotic organelles such as mitochondria and the import of bacteriocins in Gram-negative bacteria.
Tuesday, October 24, 2017 5:15 pm Lecture hall 35/E01