[{"key":"dc.contributor.author","value":"King, Dustin T.","language":null},{"key":"dc.date.accessioned","value":"2016-01-08T22:02:34Z","language":null},{"key":"dc.date.available","value":"2016-07-31T00:00:00","language":null},{"key":"dc.date.issued","value":"2016","language":null},{"key":"dc.identifier.uri","value":"http:\/\/hdl.handle.net\/2429\/56341","language":null},{"key":"dc.description.abstract","value":"Bacterial diseases have an enormous impact on human health. The most widespread class of human antibacterials is the \u03b2-lactams that target the transpeptidase activity of penicillin-binding proteins, which are responsible for cross-linking the peptidoglycan cell-wall. However, bacteria have gained resistance to all major classes of \u03b2-lactams. To protect the clinical utility of the \u03b2-lactams it is essential to understand the structural basis for this resistance. This thesis aims to better understand the molecular details governing extended-spectrum \u03b2-lactamase mediated \u03b2-lactam resistance, and to gain insights into inhibition of these emerging resistance factors.\r\n          Recently, a novel resistance factor known as the New Delhi Metallo-\u03b2-Lactamase-1 has been found to confer enteric pathogens such as Escherichia coli and Klebsiella pneumoniae with nearly complete resistance to all \u03b2-lactams. The 2.1\u00c5 resolution crystal structure of K. pneumoniae holo-NDM-1 revealed an expansive active site, which we propose leads to a broader \u03b2-lactam substrate specificity. Furthermore, NDM-1 localizes to the bacterial outer-membrane by sucrose density gradient centrifugation. The structural details underpinning the broad-spectrum resistance of NDM-1 was further investigated by analysis of the protein in complex with hydrolyzed \u03b2-lactams as well as bound to the inhibitor L-captopril.  An analysis of the NDM-1 active site in these structures reveals key features important for the informed design of novel inhibitors of NDM-1 and other metallo-\u03b2-lactamases.\r\n          The novel diazabicyclooctane (DBO) avibactam inhibits a wider range of serine \u03b2-lactamases than has been previously observed with clinical \u03b2-lactamase inhibitors. To understand the molecular basis and spectrum of inhibition by avibactam, we provide structural and mechanistic analysis of the compound in complex with important class A and D serine \u03b2-lactamases. A kinetic analysis of key active-site mutants for class A \u03b2-lactamase CTX-M-15 allows us to propose a validated mechanism for avibactam-mediated \u03b2-lactamase inhibition including a unique role for S130, which acts as a general base. We then show that avibactam derivatives retain \u03b2-lactamase inhibitory properties but also exhibit considerable antimicrobial activity against clinically relevant bacteria via targeting penicillin-binding proteins.  Our results provide evidence that structure-activity relationship studies for the purposes of drug discovery must consider both \u03b2-lactamases and penicillin-binding proteins as targets.","language":"en"},{"key":"dc.language.iso","value":"eng","language":"en"},{"key":"dc.publisher","value":"University of British Columbia","language":"en"},{"key":"dc.rights","value":"Attribution-NonCommercial-NoDerivs 2.5 Canada","language":"*"},{"key":"dc.rights.uri","value":"http:\/\/creativecommons.org\/licenses\/by-nc-nd\/2.5\/ca\/","language":"*"},{"key":"dc.title","value":"Protecting our beta-lactam antibiotic assets : structural investigation of beta-lactamases","language":"en"},{"key":"dc.type","value":"Text","language":null},{"key":"dc.degree.name","value":"Doctor of Philosophy - PhD","language":"en"},{"key":"dc.degree.discipline","value":"Biochemistry and Molecular Biology","language":"en"},{"key":"dc.degree.grantor","value":"University of British Columbia","language":"en"},{"key":"dc.date.graduation","value":"2016-02","language":"en"},{"key":"dc.type.text","value":"Thesis\/Dissertation","language":null},{"key":"dc.description.affiliation","value":"Medicine, Faculty of","language":null},{"key":"dc.description.affiliation","value":"Biochemistry and Molecular Biology, Department of","language":null},{"key":"dc.degree.campus","value":"UBCV","language":"en"},{"key":"dc.description.scholarlevel","value":"Graduate","language":"en"}]