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School of Biological and Chemical Sciences

Megan Downes

PhD student

Email: m.f.downes@qmul.ac.uk

Profile

Project title: Molecular intervention: Disrupting bacterial machinery using Directed Evolution

Summary: Antibiotic resistance poses a large problem in the modern world. The advent of antibiotics greatly increased life expectancy, due to their broad range of action in treating many bacterial pathogens. However, wide-spread use, and often misuse has led to the rise in antibiotic resistance. The opportunistic pathogen Pseudomonas aeruginosa is a common cause of infection in burn injuries and chronic lung infections in people with cystic fibrosis. P. aeruginosa utilises the Type 3 Secretion System (T3SS), a large needle-like assembly, to infect host cells. The T3SS has many components which are recruited by a series of chaperones in a strictly hierarchical manner, disrupting this abrogates the assembly of the functional T3SS.  These chaperones have recently become of interest as potential therapeutics. By producing mutants that bind to their cognate partner more strongly than the wild type chaperone, key T3SS components can be sequestered within the bacterium and thus, the pathogenicity abrogated. This project is focusing on PcrH, the joint chaperone for translocators PopB and PopD, two proteins responsible for creating the pore in the host cell wall to allow entry of pathogenic proteins. Previous students used directed evolutio to select for PcrH mutants that bind with high affinity to PopB and PopD respectively. This project initially aims to assess their potential as therapeutics.  

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