Matching Items (132)
Description
The need for a renewable and sustainable light-driven energy source is the motivation for this work, which utilizes a challenging, yet practical and attainable bio-inspired approach to develop an artificial oxygen evolving complex, which builds upon the principles of the natural water splitting mechanism in oxygenic photosynthesis. In this work, a stable framework consisting of a three-dimensional DNA tetrahedron has been used for the design of a bio-mimic of the Oxygen-Evolving Complex (OEC) found in natural Photosystem II (PSII). PSII is a large protein complex that evolves all the oxygen in the atmosphere, but it cannot be used directly in artificial systems, as the light reactions lead to damage of one of Photosystem II's core proteins, D1, which has to be replaced every half hour in the presence of sunlight. The final goal of the project aims to build the catalytic center of the OEC, including the Mn4CaCl metal cluster and its protein environment in the stable DNA framework of a tetrahedron, which can subsequently be connected to a photo-stable artificial reaction center that performs light-induced charge separation. Regions of the peptide sequences containing Mn4CaCl ligation sites are implemented in the design of the aOEC (artificial oxygen-evolving complex) and are attached to sites within the tetrahedron to facilitate assembly. Crystals of the tetrahedron have been obtained, and X-ray crystallography has been used for characterization. As a proof of concept, metal-binding peptides have been coupled to the DNA tetrahedron which allowed metal-containing porphyrins, specifically Fe(III) meso-Tetra(4-sulfonatophenyl) porphyrin chloride, to be encapsulated inside the DNA-tetrahedron. The porphyrins were successfully assembled inside the tetrahedron through coordination of two terminal histidines from the orthogonally oriented peptides covalently attached to the DNA. The assembly has been characterized using Electron Paramagnetic Resonance (EPR), optical spectroscopy, Dynamic Light Scattering (DLS), and x-ray crystallography. The results reveal that the spin state of the metal, iron (III), switches during assembly from the high-spin state to low-spin state.
ContributorsRendek, Kimberly Nicole (Author) / Fromme, Petra (Thesis advisor) / Chen, Julian (Committee member) / Ros, Alexandra (Committee member) / Arizona State University (Publisher)
Created2012
Description
Coronaviruses are a medically significant group of viruses that cause respiratory and enteric infections in humans and a broad range of animals. Coronaviruses assemble at the internal membranes of the endoplasmic reticulum- Golgi intermediate compartment (ERGIC). While there is a basic understanding of how viruses assemble at these membranes, the full mechanistic details are not understood. The coronavirus envelope (E) protein is a small multifunctional viroporin protein that plays a role in virus assembly but its function is unknown. The two goals of this study were : 1. To identify and analyze the localization of MHV E and 2. To identify the functions of conserved residues in the tail of the E protein. This study closely examined the localization, dynamics and mobility of the mouse hepatitis virus (MHV) E protein to gain insight into its functions. The results from the first aim of this study showed that the MHV E protein localizes at the site of assembly in the ERGIC-Golgi region based on analysis by immunofluorescence and correlative electron microscopy. A novel tetra-cysteine tagged MHV E protein was used to study the dynamics of the protein in cells. A recombinant MHV E Lumio virus was used to study the trafficking and mobility of the E protein. Live cell imaging and surface biotinylation confirmed that the E protein does not traffic to the cell surface. Fluorescence recovery after photo-bleaching (FRAP) analyses revealed that the E protein is mobile at the site of localization. As a part of the second aim, conserved prolines and tyrosine in the tail of the protein were targeted by site directed mutagenesis and analyzed for functionality. While none of the residues were absolutely essential for localization or virus production, the mutations had varying degrees of effect on envelope formation, protein stability and virus release. Differential scanning calorimetry data suggests that the proline and tyrosine residues enhance interaction with lipids. A wild type (WT) peptide contained the conserved residues was also able to significantly reduce the hexagonal phase transition temperature of lipids, whereas a mutant peptide with alanine substitutions for the residues did not cause a temperature shift. This suggests that the peptide can induce a negative curvature in lipids. The E protein may be playing a role as a scaffold to allow membrane bending to initiate budding or possibly scission. This data, along with the localization data, suggests that the E protein plays a mechanistic role at the site of virus assembly possibly by remodeling the membrane thereby allowing virus budding and/or scission.
ContributorsVenkatagopalan, Pavithra (Author) / Hogue, Brenda G (Thesis advisor) / Jacobs, Bertram L (Committee member) / Roberson, Robert W. (Committee member) / Fromme, Petra (Committee member) / Arizona State University (Publisher)
Created2012
Description
A Sense Of is a performance-based work that addresses the effects of the transformation of space, time, and energy through the various sensory modes. The work is an invitation to the artist's perspective of the world, which is combined with the performers' creative voices and interpretations of the artist's explorations into sensory awareness. The movement installation entitled A Sense Of was presented in November 2011. This document presents an overview of the project. It addresses relevant literature, examines the creative process used in the work, and provides an analysis of the project as a whole.
ContributorsUllom, Kathryn (Author) / Standley, Eileen (Thesis advisor) / Fitzgerald, Mary (Committee member) / Schupp, Karen (Committee member) / Klett, Mark (Committee member) / Arizona State University (Publisher)
Created2012
Description
Membrane protein structure is continuing to be a topic of interest across the scientific community. However, high resolution structural data of these proteins is difficult to obtain. The amino acid transport protein, Outer Envelope Protein, 16kDa (OEP16) is a transmembrane protein channel that allows the passive diffusion of amino acids across the outer chloroplast membrane, and is used as a model protein in order to establish methods that ultimately reveal structural details about membrane proteins using nuclear magnetic resonance (NMR) spectroscopy. Methods include recombinant expression of isotope enriched inclusion bodies, purification and reconstitution in detergent micelles, and pre-characterization techniques including circular dichroism (CD) spectroscopy, dynamic light scattering (DLS), and high pressure liquid chromatography (HPLC). High resolution NMR spectroscopy was able to assign 99% of the amide backbone and the chemical shifts provided detailed secondary structure of OEP16 on a per residue basis using the software TALOS+. Relaxation studies explored the intramolecular dynamics of OEP16 and results strongly support the resonance assignments. Successful titration studies were able to locate residues important for amino acid binding for import into the chloroplast as well as provide information on how the transmembrane helices of OEP16 are packed together. For the first time there is experimental evidence that can assign the location of secondary structure in OEP16 and creates a foundation for a future three dimensional structure.
ContributorsZook, James Duncan (Author) / Fromme, Petra (Thesis advisor) / Chen, Julian (Committee member) / Wachter, Rebekka (Committee member) / Arizona State University (Publisher)
Created2012
Description
The green fluorescent protein (GFP)-like fluorescent proteins play an important role for the color of reef-building corals. Different colors of extant coral fluorescent proteins (FPs) have evolved from a green ancestral protein. Interestingly, green-to-red photoconversion FPs (Kaede-type Red FPs) are only found in clade D from Scleractinia (Faviina suborder). Therefore, I focus on the evolution of Kaede-type FPs from Faviina suborder ancestral FP. A total of 13 mutations have been identified previously that recapitulate the evolution of Kaede-type red FPs from the ancestral green FP. To examine the effect of each mutation, total ten reconstructed FPs were analyzed and six x-ray crystal structures were solved. These substitutions created a more hydrophilic environment around the carbonyl group of Phe61. Also, they increased the flexibility of the c-terminal chain, which keeps it from interacting with the entrance of the putative solvent channel. The photoconversion reaction shows a twophase kinetics. After the rapid initial phase, the overall reaction followed the firstorder kinetics. Based on the crystal structure analysis, I propose a new mechanism for Kaede-type FP photoconversion process, which a proton transfers via Gln38 to the carbonyl group of Phe61.
ContributorsKim, Hanseong (Author) / Wachter, Rebekka M. (Thesis advisor) / Fromme, Petra (Committee member) / Redding, Kevin E (Committee member) / Arizona State University (Publisher)
Created2012
Description
The heliobacterial reaction center (HbRC) is widely considered the simplest and most primitive photosynthetic reaction center (RC) still in existence. Despite the simplicity of the HbRC, many aspects of the electron transfer mechanism remain unknown or under debate. Improving our understanding of the structure and function of the HbRC is important in determining its role in the evolution of photosynthetic RCs. In this work, the function and properties of the iron-sulfur cluster FX and quinones of the HbRC were investigated, as these are the characteristic terminal electron acceptors used by Type-I and Type-II RCs, respectively. In Chapter 3, I develop a system to directly detect quinone double reduction activity using reverse-phase high pressure liquid chromatography (RP-HPLC), showing that Photosystem I (PSI) can reduce PQ to PQH2. In Chapter 4, I use RP-HPLC to characterize the HbRC, showing a surprisingly small antenna size and confirming the presence of menaquinone (MQ) in the isolated HbRC. The terminal electron acceptor FX was characterized spectroscopically and electrochemically in Chapter 5. I used three new systems to reduce FX in the HbRC, using EPR to confirm a S=3/2 ground-state for the reduced cluster. The midpoint potential of FX determined through thin film voltammetry was -372 mV, showing the cluster is much less reducing than previously expected. In Chapter 7, I show light-driven reduction of menaquinone in heliobacterial membrane samples using only mild chemical reductants. Finally, I discuss the evolutionary implications of these findings in Chapter 7.
ContributorsCowgill, John (Author) / Redding, Kevin (Thesis advisor) / Jones, Anne (Committee member) / Fromme, Petra (Committee member) / Arizona State University (Publisher)
Created2012
Description
Lyme disease is a common tick-borne illness caused by the Gram-negative bacterium Borrelia burgdorferi. An outer membrane protein of Borrelia burgdorferi, P66, has been suggested as a possible target for Lyme disease treatments. However, a lack of structural information available for P66 has hindered attempts to design medications to target the protein. Therefore, this study attempted to find methods for expressing and purifying P66 in quantities that can be used for structural studies. It was found that by using the PelB signal sequence, His-tagged P66 could be directed to the outer membrane of Escherichia coli, as confirmed by an anti-His Western blot. Further attempts to optimize P66 expression in the outer membrane were made, pending verification via Western blotting. The ability to direct P66 to the outer membrane using the PelB signal sequence is a promising first step in determining the overall structure of P66, but further work is needed before P66 is ready for large-scale purification for structural studies.
ContributorsRamirez, Christopher Nicholas (Author) / Fromme, Petra (Thesis director) / Hansen, Debra (Committee member) / Department of Physics (Contributor) / School of Molecular Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
My intention with this project was multifaceted; my goal was to articulate in words and share through physical embodiment what dance means to me and how dance has helped shape me as an individual. In doing so, I delved into an exploration of defining dance and its role within my life and in society at large. Inspired by the black and white, silent film The Artist, I began pondering how important external elements such as music, lighting, and color are when choreographing work and furthermore sharing it with an audience. For most mainstream concert dance choreographers, these elements are an integral part of the artistic process and factor into the totality of a performance experience as a work comes into fruition. The title of my thesis, A Composition of Dance, is a play on words in my attempt to challenge my own notion of dance and investigate how one's senses and environment can influence one's perception of dance from both the performer and audience perspective.
ContributorsGiordano, Erin Noele (Author) / Schupp, Karen (Thesis director) / Rex, Melissa (Committee member) / Britt, Melissa (Committee member) / Barrett, The Honors College (Contributor) / School of Nutrition and Health Promotion (Contributor) / School of Dance (Contributor)
Created2013-05
Description
Membrane proteins located within or as attachments to the cell membrane play critical roles in many essential cellular functions and host-pathogen interactions. Knowledge of the structure and function of membrane proteins in pathogenic species can allow for the development of specific vaccines and therapeutic agents against the pathogen. Francisella tularensis is an intracellular pathogen that is the causative agent of the severe, life-threatening infection, tularemia, in humans and other small mammals. F. tularensis is prevalent within the environment and is a potential bioterrorism agent due to its high virulence and its ability to be spread easily as an aerosol. The CapBCA membrane protein complex has been identified as a virulence factor of F. tularensis. This project, derived from the Membrane Proteins in Infections Diseases (MPID) Project, aims to successfully express the membrane proteins CapBCA, which are crucial to the pathogenic properties of F. tularensis. To accomplish this goal, methods for in vivo recombinant expression and purification of membrane proteins are in the process of being developed. The expression of the CapA component has been successful for some time, therefore, the goal of this study is to develop an approach toward recombinant in vivo membrane protein expression of both the CapB and CapC components of the CapBCA membrane protein complex. In this study, the CapB and CapC components were expressed for the first time in vivo through the use of the novel MPID vector, pelB-MBP. The expression of the CapB and CapC components will allow for large-scale expressions to commence with the end goal of determining the crystal structures of the individual proteins or the complex. Ultimately, it is hoped that knowledge of these molecular structures can lead to the development of a vaccine or other therapeutic agents against this pathogen.
ContributorsTrimble, Kelli Lauren (Author) / Fromme, Petra (Thesis director) / Hansen, Debra (Committee member) / Barrett, The Honors College (Contributor) / Department of Chemistry and Biochemistry (Contributor) / School of Film, Dance and Theatre (Contributor)
Created2015-05
Description
Today's prison industrial complex in the United States often dehumanizes inmates simply because they are criminals. Members of the free society are generally too far removed from the inside of prisons that most people do not see the harsh and cruel conditions for and treatment of prisoners. As a Dance and Justice Studies major at Arizona State University, I was curious about how to intertwine my interests in dance and justice. This paper chronicles my exploration of adding a human rights issue to my dance practice through choreographing a solo dance performance based on Cleve Foster's unusual experience on death row. Research on theories of prison and punishment in American society combined with physical research in the dance studio enabled me to create a solo performance that shed light on the inhumane conditions for and treatment of prison inmates in today's society. Through the process, I found that some elements of my dance practice stayed the same, while others changed. This informed me of what continuously remains important to me, while allowing me to expand my personal dance practice. I ultimately discovered a bridge between my two passions, dance and justice, and learned a meaningful way to convey a contemporary social justice issue to the general public.
ContributorsKerr, Elena Marie (Author) / Schupp, Karen (Thesis director) / Vissicaro, Pegge (Committee member) / Barrett, The Honors College (Contributor) / Herberger Institute for Design and the Arts (Contributor) / School of Social Transformation (Contributor) / School of Film, Dance and Theatre (Contributor)
Created2015-05