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Title: Structural studies into the mechanisms of pathogenicity of Burkholderia
Author: Owen, Hayley
ISNI:       0000 0004 7230 4142
Awarding Body: University of Sheffield
Current Institution: University of Sheffield
Date of Award: 2016
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The aim of this thesis was to structurally characterise proteins potentially involved in the virulence mechanisms utilised by B. pseudomallei, the causative agent of the human disease melioidosis. The first project aims to continue investigations into an operon of four proteins of largely unknown structure and function, BPSS0211-BPSS0214. Structural studies on BPSS0211 provide evidence for conformational changes of its helical DUF1843 domain and a novel quaternary structure as part of its function. Structural studies of the DUF1842 domain of BPSS0212 reveal a lipocalin-like ß-barrel fold, suggesting it may act as a ligand-binding domain. Biochemical studies indicated that BPSS0212 and BPSS0213 interact to form a complex of approximately 350kDa molecular weight, via the C-terminal DUF1843 domains. The structure of this complex was solved and revealed that eight subunits each of BPSS0212 and BPSS0213 associate into the presumed biologically active molecule. The second project involves investigations into the type VI secretion system, which is known to be involved in virulence and is a complex composed of the products of at least 13 genes. Structural studies focussed on a putative predicted baseplate protein, TssA. Sequence comparisons have indicated across multiple species two distinct families of TssA, TssA-1 and TssA-2. Two domains, an N- and C-terminal domain, were identified from B. cenocepacia TssA-1. Constructs of the two TssA domains were produced, and the structures solved separately. The structure of the N-terminal domain has two bundles of helices forming an L-shaped molecule, and the combination of sequence and structure analysis shows that the TssA-2 N-terminal domain must be a tandem repeat of a structure resembling the first section of the N-terminal domain of TssA-1. The C-terminal domain forms a ring of 32 monomers with D16 symmetry, which has a distinctly different structure to the previously solved structure of the C-terminal domain of the TssA-2 family.
Supervisor: Rice, David ; Baker, Patrick Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available