This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
G protein-coupled receptors (GPCRs) are a large family of proteins involved in the cell signaling and regulation of many biological and pathological processes in the human body. To fully understand their functions, various approaches are needed. This work combines several techniques to advance the study of GPCRs with the overarching…
G protein-coupled receptors (GPCRs) are a large family of proteins involved in the cell signaling and regulation of many biological and pathological processes in the human body. To fully understand their functions, various approaches are needed. This work combines several techniques to advance the study of GPCRs with the overarching goal of pursuing X-ray crystallization using lipidic cubic phase (LCP). In meso, or LCP crystallization method involves imbedding the GPCR into a lipid membrane-mimetic material which spontaneously forms when monoacylglycerols (MAGs) are mixed at the correct hydration level and temperature. It provides a stable environment for GPCRs and has been established as the most common method to resolve structural details of GPCRs (Chapter 2). Yet, before crystallization, GPCRs need to be put through several rounds of optimization of the construct design, including truncation of N- and C- termini, fusing different soluble proteins, and mutating the receptor (Chapter 3). Other methods were also used to gain structural insights into GPCR interactions, such as coarse-grained molecular dynamic simulations, which showed the specific regions of interactions with cholesterol molecules imbedded in the membranes (Chapter 4). This study demonstrated β2-adrenergic receptor (β2AR), a GPCR, as a model of a cholesterol-sensitive receptor. Mutations were made to test the effect of removing specific residues of interest on cholesterol stabilization through the LCP-Tm assay, producing results that align with the simulation data. Finally, the goal of the last study is to provide a guide to identify which host lipids form stable LCP phases for different applications (Chapter 5). Small angle X-ray scattering is used to identify phases in hundreds of different precipitant conditions in the search of suitable host lipid for LCP studies. The results present a systematic overview of the compatibility of common MAGs by screening them against different precipitant solutions including varying salts and polyethylene glycol (PEG) concentrations, different PEG sizes, the presence of detergent or protein in the sample, and the addition of cholesterol. Together, these studies present a variety of methods to advance the structural studies of GPCRs using LCP
