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http://hdl.handle.net/1974/727
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| Title: | NMR and Biophysical Studies of Modular Protein Structure and Function |
| Authors: | Chitayat, Seth |
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| Keywords: | NMR spectroscopy
Protein structure
Protein-ligand interactions
Extracellular proteins
Clostridium perfringens
Apolipoproteins
Low density lipoprotein
Bacterial pathogens
Cardiovascular disease
Molecular biology
Biochemistry
Modular proteins |
| Issue Date: | 2007 |
| Series/Report no.: | Canadian theses |
| Abstract: | Proteins modularity enhances the multi-functionality and versatility of proteins by providing such properties as multiple and various ligand-binding sites, increased ligand affinity through the avidity effect, and the juxtaposition of ligand-binding modules near catalytic domains. An NMR-based "dissect-and-build" approach to studying modular protein structure and function has proven very successful, whereby modules are initially characterized individually and then correlated with the overall function of a protein. We have used the dissect-and-build approach and NMR to study two modular protein systems.
Chapter 2 details the NMR solution structure of the weak-lysine-binding kringle IV type 8 (KIV8) module from the apolipoprotein(a) (apo(a)) component of lipoprotein(a) was determined and its ligand-binding properties assessed. In vitro studies have demonstrated the importance of the apo(a) KIV7 and KIV8 modules in mediating specific lysine-dependent interactions with the apolipoproteinB-100 (apoB-100) component of LDL in the initial non-covalent step of lipoprotein assembly. Notable differences identified in the lysine binding site (LBS) of the KIV8 were deemed responsible for the differential modes of apoB-100 recognition by KIV7 and KIV8. In addition, the KIV8 structure has brought to light the importance of an RGD sequence at the N-terminus of the apo(a) KIV8 module, which may mediate important apo(a)-integrin interactions.
In Chapters 3-6, structure-function studies of the CpGH84C X82 and the CpGH84A dockerin-containing modular pair were conducted to understand how the varying modularity unique to the C-terminal regions of the secreted multi-modular family 84 glycoside hydrolases influences the spreading of Clostridium perfringens. Identification of a CpGH84C cohesin module (X82), and the structural characterization of a dockerin-containing modular pair provides the first evidence for multi-enzyme complex formation mediated by non-cellulosomal cohesin-dockerin interactions. The formation of large hydrolytic enzyme complexes introduces a novel mechanism by which C. perfringens may enhance its role in pathogenesis. |
| Description: | Thesis (Ph.D, Biochemistry) -- Queen's University, 2007-09-27 11:46:38.753 |
| URI: | http://hdl.handle.net/1974/727 |
| Appears in Collections: | Biochemistry Graduate Theses
Queen's Theses & Dissertations
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