The Gram-positive bacterium Clostridium difficile is the primary causative agent of antibiotic-associated diarrhoea and kills tens of thousands of people around the world every year. While a significant proportion of research into C. difficile has focused on the toxins produced by the bacterium, which are responsible for disease aetiology, effective methods of prevention and treatment are likely to result from research into a range of aspects of the bacterium.One such aspect is the paracrystalline layer of protein found on the cell surface of a wide range of bacterial species and virtually all archaea known as an S-layer. The S-layer of C. difficile is mostly formed by the low- and high-molecular weight S-layer proteins LMW SLP and HMW SLP. HMW SLP possesses three cell wall binding domains. The C. difficile genome contains 28 other genes that also code for proteins with three cell wall binding domains, many of these proteins also possess other domains that confer a specific function on the protein.In this thesis work resulting in the determination of high-resolution structures of the “functional” regions of three proteins coded for by these genes is described: Cwp84, Cwp19 and Cwp2. This work required use of experimental phasing methods and advanced molecular replacement techniques. The structures reveal information on the role of these proteins in the formation of the S-layer, carbohydrate metabolism and host cell adhesion, respectively. This adds to the growing body of knowledge on the S-layer of C. difficile and may, in the future, contribute to the development of novel therapeutics against the bacterium.
|Date of Award||30 Sep 2017|
|Supervisor||Ravi Acharya (Supervisor) & Clifford C. Shone (Supervisor)|