Dissecting protein-protein interactions facilitating secretion of the virulence factor EspC by enteropathogenic Escherichia coli

Bishop, Keith (2009) Dissecting protein-protein interactions facilitating secretion of the virulence factor EspC by enteropathogenic Escherichia coli. MPhil thesis, University of Nottingham.

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Abstract

This study investigates the domain structure and secretion of the autotransporter (AT) EspC, secreted by enteropathogenic Escherichia coli (EPEC). The boundaries of the archetypical signal peptide and beta-domain surrounding the passenger domain of EspC were established. Then, structural modelling was used to define a region of EspC between the passenger- and β-domains, termed the inter-domain, which may comprise a passenger- chaperone domain. Yeast two-hybrid and co-purification approaches were subsequently used to assess protein-protein interactions between individual EspC domains and with a putative secretion accessory factor, YbgC. Direct interaction between the EspC passenger- and inter-domain was observed, consistent with a proposed chaperone function for the inter-domain. Structural modelling identified conserved surface motifs within the inter-region as targets for mutagenesis to determine their influence upon EspC secretion. Complementation of an EPEC espC mutant strain with inter-domain EspC mutants showed profound affects on secretion. Furthermore, these mutants had a dominant-negative affect on wildtype EspC secretion, affecting bacterial cell viability.

These results provide the first characterisation of the putative EspC inter-domain and implicate it in facilitating efficient AT secretion. Observations from this work provide a foundation and rational direction for future research and a broad complement of research tools which will greatly facilitate future studies.

Item Type:Thesis (MPhil)
Supervisors:Delahay, R.M.
Hardie, K.
Uncontrolled Keywords:EspC, Y2H, Yeast two-hybrid, Enteropathogenic Escherichia coli, EPEC
Faculties/Schools:UK Campuses > Faculty of Medicine and Health Sciences > School of Molecular Medical Sciences
ID Code:1023
Deposited By:Mr Keith Bishop
Deposited On:05 Mar 2010 11:33
Last Modified:26 Nov 2012 10:32

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