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Expression and folding studies of the ankyrin repeat domain of the capsaicin receptor

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Description: The capsaicin receptor, TRPV1, is a member of the TRP (transient receptor potential) superfamily of cation channels that are responsible for detecting and integrating a wide range of physical and chemical stimuli. TRPV1 is a non-selective cation channel that is activated by noxious temperatures (> 43°C), acid, capsaicin, the chemical ingredient in 'hot peppers', and inflammatory mediators like anandamide. The channel is formed from the self assembly of four identical subunits consisting of 838 amino acid residues with intracellular amino and carboxy termini. The amino and carboxy terminus have implications in the regulation of TRPV1 function. The amino terminus consists of 432 amino acid residues and contains five putative ankyrin repeat domains. Ankyrin repeat domains are a modular protein motif consisting of a repeating 33 amino acid segment that is known to modulate protein-protein interactions. Structural and biophysical characterization of amino terminal fragments of TRPV1 could afford a detailed understanding of the regulation and activation of the channel. It was the aim of this research to characterize three recombinant protein constructs encompassing the ankyrin repeat domains of TRPV1. The three constructs were: ARD234, encompassing four putative ankyrin repeat domains, ARD1234 encompassing five putative ankyrin repeat domains, and TRPV1(432)-GFP, which encompasses the entire amino terminus fused to GFP. All three protein constructs were expressed in the E. coli strain BL21*(DE3). However, only ARD1234 was purified. ARD1234 was purified from inclusion bodies, but attempts to refold the protein failed. It was determined that ARD1234 aggregated faster than it refolded under the conditions implemented in this work.
Language: English
Format: Degree Work