Biochemistry, Biophysics, and Structural Biology Commons^™

Molecular Characterization Of Compartment Boundary Formation During Epithelial Remodeling In Drosophila Melanogaster, Samia Parveen

Graduate Theses and Dissertations

The ability of epithelial cells to self-organize is crucial for the development of proper tissue structures and organs in multi-cellular organisms. Epithelia consist of inter-connected cells that form flat sheets, and specific groups of cells within these sheets are partitioned into distinct compartments via compartment boundaries (CBs). These CBs are specialized interfaces between cells characterized by stable, high-tension actomyosin cables, which act as fences to prevent movements between adjacent compartments during tissue reorganization. In the early Drosophila embryo, CBs are established in response to the asymmetrical localization of two cell-surface proteins the Leucine-Rich Repeat (LRR) protein Tartan and the Teneurin …

Investigating And Characterizing Septin Cellular Regulators During Infection Related Development In M. Oryzae, Rinalda Proko

Graduate Theses and Dissertations

The fungus Magnaporthe oryzae causes a devastating disease of rice and wheat, called blast, which poses a major threat to food security across the planet. To enter plant tissue, M. oryzae produces a remarkable pressure-generating infection cell called an appressorium, which mechanically ruptures the tough cuticle of host leaves through the application of enormous physical force directed onto a narrow penetration structure emerging from its base. Importantly, appressorium form and functionality depends on the regulated assembly of a toroidal ring-like structure, composed of septins, which forms within its base. Septins are a family of membrane-associated GTP-binding proteins that polymerize into …

Unraveling The Biogenesis And Roles Of Iron-Sulfur Proteins During Nitrogen Fixation By Methanosarcina Acetivorans, Jasleen Saini

Graduate Theses and Dissertations

Iron-sulfur (Fe-S) clusters, the ancient cofactors found in proteins across all life forms, play vital roles in numerous cellular processes. Fe-S clusters exhibit structural diversity, ranging from simple to complex forms. Methanogens are anaerobic archaea that produce methane as a metabolic by-product through methanogenesis, a process dependent on numerous Fe-S proteins. Notably, methanogens are capable of fixing nitrogen (diazotrophy) facilitated by the enzyme complex called nitrogenase, which contains both simple and complex Fe-S clusters. While methanogens possess the largest number of Fe-S proteins, the factors involved in Fe-S cluster biogenesis remain largely unknown. Bacteria possess three distinct and well-characterized Fe-S …

The Roles Of Estrogen Receptor Alpha-Interacting Rnas And Exosomes In Breast Cancer, And E-Cadherin In Carcinomas, Brihget Catalina Sicairos-Meza

Graduate Theses and Dissertations

Carcinomas are malignancies of epithelial cells and account for >80% of cancer-related deaths. Approximately 75% of breast cancers express estrogen receptor alpha (ERα). ERα promotes breast cancer progression by enhancing cancer cell proliferation. Tamoxifen is commonly used to treat ERα-positive breast cancers but can result in endocrine therapy resistance. The mechanisms underlying endocrine therapy resistance remain elusive. The Du lab recently found that ERα is an RNA-binding protein. However, the significance of the ERα-RNA interaction is unknown. We fractionated ERα-positive MCF7 cells into cytoplasmic and nuclear fractions, followed by immunoprecipitation of ERα with associated RNAs and RNA-sequencing. We identified many …

Silver Ions Inhibit Bacterial Movement And Stall Flagellar Motor, Benjamin Russell, Ariel Rogers, Ryan Yoder, Matthew Kurilich, Venkata Rao Krishnamurthi, Jingy Chen, Yong Wang

Physics Faculty Publications and Presentations

Silver (Ag) in different forms has been gaining broad attention due to its antimicrobial activities and the increasing resistance of bacteria to commonly prescribed antibiotics. However, various aspects of the antimicrobial mechanism of Ag have not been understood, including how Ag affects bacterial motility, a factor intimately related to bacterial virulence. Here, we report our study on how Ag⁺ ions affect the motility of E. coli bacteria using swimming, tethering, and rotation assays. We observed that the bacteria slowed down dramatically by >70% when subjected to Ag⁺ ions, providing direct evidence that Ag⁺ ions inhibit the motility …

The Alternating Access Mechanism In Mammalian Multidrug Resistance Transporters And Their Bacterial Homologs, Shadi A. Badiee, Ugochi H. Isu, Ehsaneh Khodadadi, Mahmoud Moradi

Chemistry & Biochemistry Faculty Publications and Presentations

Multidrug resistance (MDR) proteins belonging to the ATP-Binding Cassette (ABC) transporter group play a crucial role in the export of cytotoxic drugs across cell membranes. These proteins are particularly fascinating due to their ability to confer drug resistance, which subsequently leads to the failure of therapeutic interventions and hinders successful treatments. One key mechanism by which multidrug resistance (MDR) proteins carry out their transport function is through alternating access. This mechanism involves intricate conformational changes that enable the binding and transport of substrates across cellular membranes. In this extensive review, we provide an overview of ABC transporters, including their classifications …

Studying The Phosphorylation Of Isocitrate Dehydrogenase In Humans, Hannah Smith

Chemistry & Biochemistry Undergraduate Honors Theses

Isocitrate dehydrogenase is an important enzyme in the citric acid cycle where it catalyzes the oxidative decarboxylation of isocitrate to alpha-ketoglutarate. While there are three isoforms of isocitrate dehydrogenase (IDH1, IDH2, and IDH3), this research will focus on IDH1. The phosphorylation of isocitrate dehydrogenase is a process that has been linked to the formation of both luminal-like and basal-like breast cancer. Despite these correlations, the mechanisms that cause breast cancer development are unknown. To examine this, an enzyme activity assay for each phosphorylation variant and crystallization were conducted. The results of these indicate that phosphorylation at each site (IDH1-T77, IDH1-S188, …

Expression, Purification, And Characterization Of Fibroblast Growth Factor 19, Elizabeth Ford

Chemistry & Biochemistry Undergraduate Honors Theses

Fibroblast growth factors (FGFs) are a family of signaling proteins with diverse biological functions. Fibroblast growth factor 19 (FGF19) regulates several vital physiological processes, including bile acid, glucose, and lipid homeostasis. However, its therapeutic potential is limited by its structural instability. The purpose of this study is to express, purify, and characterize recombinant FGF19 to build the foundation for the creation of stable mutants, which can be used to treat a variety of common diseases including type 2 diabetes, atherosclerosis, and nonalcoholic fatty liver disease. The parameters for overexpression in Escherichia coli were optimized according to optical density, inducer concentration, …

Expression, Characterization, And Investigation Of The Thermal Stability Of Fibroblast Growth Factor (Fgf) 19, Ridhikaanth Kalaiselvan

Chemistry & Biochemistry Undergraduate Honors Theses

Fibroblast growth factors are a family of cell signaling proteins that have the ability to bind to heparin and are involved in a wide range of physiological functions, such as angiogenesis, cell differentiation, cell proliferation, cell morphogenesis, and wound healing. Fibroblast growth factor (FGF) 19 is a signaling protein belonging to this large family of fibroblast growth factors (FGFs). FGF19 has a pronounced effect on various biological processes, including cell proliferation, cholesterol and lipid catabolism, and glucose homeostasis. As such, FGF19 is known to play an integral role in regulating many metabolic diseases, which piques the interest of the science …

A Characterization Of The Quadruple Mutant Of The Fgf1-Fgf2 Heterodimer, Kenlee Claborn

Chemistry & Biochemistry Undergraduate Honors Theses

Human Fibroblast Growth Factor (FGF) was first identified as a protein whose function was to aid in cell proliferation, but now, FGF has been determined to consist of over 23 different proteins in 7 different subfamilies with three different types of cell-signaling purposes.¹ In the first subfamily are the two most notable and studied proteins, Fibroblast Growth Factor 1 (FGF1) and Fibroblast Growth Factor 2 (FGF2). Respectively, they are known for their unique capabilities of cell proliferation/mitogenesis and angiogenesis.² To induce the cell-signaling pathway that leads to the function of these proteins, FGF1 and FGF2 binds to their …

Differential Electrostatic Interaction Patterns In Sars-Cov-1 And Sars-Cov-2 Variants: A Molecular Dynamics Simulation Study, Ugochi Hope Isu

Graduate Theses and Dissertations

The SARS-related coronavirus (SARS-rCoV) is a highly contagious virus that has raised significant worldwide health concerns. It caused outbreaks in 2002-2003 and more recently in 2019-2020 with SARS-CoV-2. SARS-CoV-2 is responsible for the COVID-19 pandemic, which has resulted in a significant global impact on health and the economy. The spike protein of the virus plays a critical role in its infectivity and transmission, and the receptor-binding domain (RBD) within the spike protein is of particular interest, as it is responsible for binding to the human angiotensin-converting enzyme 2 (ACE2) receptor. In this study, we used Molecular dynamics (MD) simulations to …

Comprehensive Long- And Short- Read Sequencing Approaches To Screen The Mutational Landscape After Therapeutic Crispr-Editing For Duchenne Muscular Dystrophy, Mary Jia, Made Harumi Padmaswari, Landon Burcham, Shilpi Agrawal, Alexis Ivy, Abbey Bryan, Christopher E. Nelson

Biomedical Engineering Undergraduate Honors Theses

Duchenne muscular dystrophy (DMD) is an X-linked muscle wasting disease caused by mutations in the Dmd gene resulting in non-functional dystrophin. Adeno-associated virus (AAV)-mediated delivery of classical CRISPR systems resulting in double-stranded breaks (DSBs) has yielded promise as a curative DMD therapeutic. However, the consequences of AAV-CRISPR require more thorough characterization. PCR-enriched short-read amplicon sequencing at cut sites is the most common method of sequencing CRISPR editing, but PCR bias results in unreliable quantification of on-target edits. We analyze orthogonal long- and short-read sequencing approaches to screen the outcomes of CRISPR technologies at the DNA and RNA-level for DMD. We …

Minimal Carbon Requirements For Potential Colonizers Of Other Planets, Benjamin Tan

Biological Sciences Undergraduate Honors Theses

The NASA Office of Planetary Protection regulates the safe scientific exploration of other planets. Specifically, the office enacts rules to discourage interplanetary mission practices that would lead to the contamination of Earth-originating microbial life on other planets. Interplanetary contamination jeopardizes the potential to obtain reliable scientific evidence for extraterrestrial life. In coordination with this office, the biosignatures of potential colonizers of other celestials bodies are studied. Several organisms of Earth qualify as potential colonizers of other planets.

This experiment focused on the environment of Mars in particular. Two organisms were tested: Desulfovibrio arcticus and Desulfotalea psychrophila. Both are psychrotolerant or …

Microorganisms In Extreme Environmental Conditions, Khanh Mai Nguyen

Graduate Theses and Dissertations

Organisms are known to be able to prosper under normal and extreme environmental conditions, which are classified as mesophile and extremophile, respectively. Extremophiles can thrive under a large array of conditions, from pressures, temperatures, salinity, and pH to a combination of them. For example, to survive on the ocean floor, marine biomass must have its biomolecular machinery adapted to the high pressures and high salinity environment. Moreover, around the hydrothermal vents, aside from pressure and salinity, the microbes that live there also need to adjust to the temperature as well as the pH level. Aside from high temperatures, researchers also …

Ins And Outs Of Rocker Switch Mechanism In Major Facilitator Superfamily Of Transporters, Stephanie Sauve, Joseph Williamson, Adithya Polasa, Mahmoud Moradi

Chemistry & Biochemistry Faculty Publications and Presentations

The major facilitator superfamily (MFS) of transporters consists of three classes of membrane transporters: symporters, uniporters, and antiporters. Despite such diverse functions, MFS transporters are believed to undergo similar conformational changes within their distinct transport cycles, known as the rocker-switch mechanism. While the similarities between conformational changes are noteworthy, the differences are also important since they could potentially explain the distinct functions of symporters, uniporters, and antiporters of the MFS superfamily. We reviewed a variety of experimental and computational structural data on a select number of antiporters, symporters, and uniporters from the MFS family to compare the similarities and differences …

Simulating A Flexible Water Model As Rigid: Best Practices And Lessons Learned, Raymond Weldon, Feng Wang

Chemistry & Biochemistry Faculty Publications and Presentations

Two ways to create rigid versions of flexible models are explored. The rigid model can assume the Model’s Geometry (MG) as if the molecule is not interacting with any other molecules or the ensemble averaged geometry (EG) under a particular thermodynamic condition. Although the MG model is more straightforward to create, it leads to relatively poor performance. The EG model behaves similarly to the corresponding flexible model (the FL model) and, in some cases, agrees even better with experiments. While the difference between the EG and the FL models is mostly a result of flexibility, the MG and EG models …

Cholesterol In Class C Gpcrs: Role, Relevance, And Localization, Ugochi H. Isu, Shadi A. Badiee, Ehsaneh Khodadadi, Mahmoud Moradi

Chemistry & Biochemistry Faculty Publications and Presentations

G-protein coupled receptors (GPCRs), one of the largest superfamilies of cell-surface receptors, are heptahelical integral membrane proteins that play critical roles in virtually every organ system. G-protein-coupled receptors operate in membranes rich in cholesterol, with an imbalance in cholesterol level within the vicinity of GPCR transmembrane domains affecting the structure and/or function of many GPCRs, a phenomenon that has been linked to several diseases. These effects of cholesterol could result in indirect changes by altering the mechanical properties of the lipid environment or direct changes by binding to specific sites on the protein. There are a number of studies and …

Purification Of Anginex: An Inhibitor Of Tumor Metastasis Using Rdrd Tag, Suraj Kolluru

Inquiry: The University of Arkansas Undergraduate Research Journal

Anginex is a cytokine-like β-sheet forming peptide of 33 amino acids with potent anti-angiogenic activity.Anginex is essential in inhibiting abnormal processes caused by angiogenesis, such as tumor growth and blood vessel formation. However, Anginex has limitations, including poor stability, short half-life, complicated synthesis, and low purity. Rubredoxin dimer (RdRd) is used as a protein tag to improve stability and detection of Anginex during purification for the first time. A plasmid was designed to contain the RdRd-Anginex fusion protein. RdRd-Anginex plasmid was transformed and expressed in E. coli BL21star cells. The results show RdRd-Anginex has been purified using a Nickel Sepharose …

Cell Division Dynamics Of Escherichia Coli In Extreme Environments, Steven P. Murray

Graduate Theses and Dissertations

Life is remarkable in how resilient it can be. Many organism, classified as ex- tremophiles, can not only survive in extreme environments, but they can thrive in them. In the search for extraterrestrial life, the best candidates to harbor life exist with some kind of extreme condition. Europa, for example, is a favorite for the possibility of accommodating life as we know it within our solar system. Thought there is believed to be a liquid ocean under its icy surface, this habitat would be under immense pressures and high salinity. To best know where to look for extraterrestrial life, it …

Fiber-Based Time-Correlated Single Photon Counting As A Method For Investigating Metabolism During Tetanic Contraction Of Skeletal Muscle, Kathryn Miller Priest

Graduate Theses and Dissertations

Nicotinamide adenine dinucleotide (NAD) is a cofactor that serves to shuttle electrons during metabolic processes such as glycolysis, the tricarboxylic acid cycle, and oxidative phosphorylation (OXPHOS) [1-5]. The reduced form of NAD, NADH, is autofluorescent, making it a measurable characteristic in the investigation of metabolic changes. The fluorescence lifetime of NADH is dependent on the state of protein binding, specifically free or bound NADH, allowing for detection of metabolic shifts between glycolysis (free NADH) and OXPHOS (bound NADH) [6-16]. Fiber-coupled time-correlated single photon counting (TCSPC) equipped with an implantable needle probe can be used to measure NADH lifetime in vivo …

The Antimicrobial Resistance Plasmid Mobilome Of Salmonella Enterica And Related Enteric Species And Factors That Influence The Transfer Efficiency., Suad Algarni

Graduate Theses and Dissertations

The dynamic distribution of antimicrobial resistance genes in Salmonella enterica is considered a public health risk. S. enterica is one of the most important etiological agents of foodborne illness and has a critical impact on global human health. In S. enterica and related species, mobile genetic elements (MGEs) serve as primary vehicles for the dissemination of antibiotic resistance genes in the bacterial evolution. This dissemination can be impacted by different selective pressures that leads to diverse antibiotic response phenotypes. This project focusses on the dynamics of antimicrobial resistance genes, particularly exploring the transfer efficiency of multidrug resistance plasmids in S. …

Using Molecular Dynamics Simulations To Decipher Mechanistic Details Of Biomolecular Processes Of Biology And Biotechnology Oriented Applications, Adithya Polasa

Graduate Theses and Dissertations

Researchers in chemistry and biology often utilize computer simulations, in conjunction with experimental data, to model and predict the structures, energies, kinetics, processes, and functions of the systems that are their focus of study, ranging from single molecules to whole viruses. Here, we use molecular dynamics (MD) techniques to gain a deeper understanding of biomolecular processes in biology and biotechnology-oriented applications. Using a mixture of equilibrium and non-equilibrium MD simulations, this work describes the insertion process of YidC at the atomic level. In order to better comprehend the insertion process, several docking models of YidC-Pf3 in the lipid bilayer were …

Molecular Characterization Of Nitrogenase Regulation In Methanosarcina Acetivorans, Melissa Chanderban

Graduate Theses and Dissertations

Nitrogenase is the metalloenzyme only found in bacteria and archaea that is essential for biological nitrogen fixation (diazotrophy), but it can also serve as a catalyst in biofuel production. All diazotrophs contain a molybdenum (Mo) nitrogenase, while some species contain additional alternative nitrogenases where either vanadium (V) or iron (Fe) replace Mo in the active site cofactor. Nitrogen fixation by bacteria has been extensively studied. The limited investigation of nitrogen fixation in methanogenic archaea (methanogens) indicates production of nitrogenase is simpler than in bacteria and methanogen nitrogenase has different biochemical properties. Thus, methanogen nitrogenases provide a promising alternative for genetic …

The Binding Of The Micronutrient Transition Metals To The Alkylation Products Of Chemical Warfare Agent, Sulfur Mustard, And Thiols, Potentially Giving New Understanding To Physiological Effects Of Exposure And Increased Toxicity, Colin O'Donnell

Graduate Theses and Dissertations

Model compounds, 3,6,9-trithaiundecane-1,11-dicarboxylic acid (TTDPA), 2,5,8-trithianonane-1,9-dicarboxylic acid (TTDAA), and 1,11-diamide-3,6,9-trithiaundecane (TTDAce), closely related to the adducts formed by cysteine alkylation of the chemical weapon, sulfur mustard, were synthesized. It is shown that TTDPA forms complexes with key metal micronutrients: copper, nickel, cobalt, manganese, and zinc. Though the strength of binding to TTDPA varies, the complexes in many cases precipitate from solution. All metals produced a visible precipitate upon interaction with TTDPA under the conditions tested, however only Cu2+, Mn2+, and Zn2+ produced enough to be measured. The mass of formed precipitate seemed to peak at an equimolar ratio of TTDPA …

Comparative Analysis Of Conformational Transition Pathways In Homologous Proteins, Dylan Sebastien Ogden

Graduate Theses and Dissertations

Molecular dynamics (MD) simulations are routinely used to study the dynamics of proteins. However, conventional MD limited to the sampling of local conformational changes as the functionally important conformational transitions of proteins often extend beyond the timescales of the simulations employed, for example, membrane transport proteins. We have determined the combination of multiple MD based techniques that allows for a rigorous characterization of energetics and kinetics of large-scale conformational changes in membrane proteins. The methodology is based on biased, nonequilibrium collective variable based simulations including nonequilibrium pulling, string method with swarms of trajectories, bias-exchange umbrella sampling, and rate estimation techniques. …

Modifications Of Cellulose-Based Biomaterials For Biomedical Applications, Nour Fatema, Ruben Michael Ceballos, Chenguang Fan

Chemistry & Biochemistry Faculty Publications and Presentations

Cellulose is one of the most abundant organic compounds in nature and is available from diverse sources. Cellulose features tunable properties, making it a promising substrate for biomaterial development. In this review, we highlight advances in the physical processes and chemical modifications of cellulose that enhance its properties for use as a biomaterial. Three cellulosic products are discussed, including nanofibrillated, nanocrystalline, and bacterial cellulose, with a focus on how each may serve as a platform for the development of advanced cellulose-based biomaterials for Biomedical applications. In addition to associating mechanical and chemical properties of cellulosic materials to specific applications, a …

A Review Of Quantum Coherence And Its Effect On Photosynthetic Efficiency In Psii And Fmo Complexes, Matthew Nelson

Chemistry & Biochemistry Undergraduate Honors Theses

Photosynthesis in living organisms is one of the most efficient, natural energy harvesting processes on Earth. The absorption of light energy as photons directly energizes electrons in metabolite molecules. These molecules transfer their high energy electrons through a chain system to provide the energy needed for carbon dioxide metabolism. Recently, it has been a subject of debate how this energy transfer via electron transport achieved such high efficiency. One hypothesis is that this transfer system displays fundamentally quantum mechanical behaviors, such as coherence. Here, I will briefly define this concept in quantum mechanics, and explain the role it might play …

Determining The Full-Length Structure Of Collagenase H Using Small-Angle X-Ray Scattering, Josie Carson

Chemistry & Biochemistry Undergraduate Honors Theses

Known to cause gas gangrene, Hathewaya histolytica secretes two sister collagenases, collagenase G (Col G) and collagenase H (Col H), to degrade the triple helical structure of collagen to further infection in a host. Individual domains of Col H have been crystalized in previous studies, but methods in x-ray crystallization of full-length Col H have been unsuccessful. Using Small Angle X-Ray Scattering (SAXS) data, atomistic modeling was used to generate multiple conformations of Col H while accounting for flexibility between domains. Full-length Col H was found to adopt a two-state conformational model exhibiting a majority compact and a minority elongated …

An Analytical Method To Detect And Quantify Ll-37 In An In Vitro Co-Culture Of Activated Thp-1 Cells And Staphylococcus Aureus, Staphylococcus Epidermidis, And Pseudomonas Aeruginosa, Victoria Hunter

Graduate Theses and Dissertations

Healthcare-associated infections (HCAIs) affect 1.7 million hospitalized patients each year, resulting in over 98,000 deaths and anywhere from $28.4 to $45 billion in treatment costs. Furthermore, it has been established that more than 80% of these infections are caused by biofilms While HCAIs can be bacterial, viral, fungal, or parasitic, there are between 12 and 17 species cause 80 to 87% of all HCAIs. Among the most commonly isolated microorganisms are Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Thus, biofilms are of importance not only due to their prevalence in HCAIs but also due to the increased antibiotic …

Examining The Expression Patterns Of Desulfotalea Psychrophila Dsrab Operon And Pit At Subfreezing Temperatures And Different Concentrations Of Sulfate Salts As A Model For Mars And Icy Worlds Survival And Colonization, Sergio Luis Mosquera Mora

Graduate Theses and Dissertations

Since ancient times, Humanity has been fascinated with the idea of what lies beyond the borders of our planet. Fortunately, the combined efforts of many nations have made it possible to send unmanned spacecraft to orbit planets located close to Earth. These missions have the principal goal to collect data that could help us understand the basic environmental conditions that persist on those planets, or for evidence of past or present life. Equally important, landers and rovers have been successfully deployed to start the in-situ exploration of many planets of the Solar System. Among them, Mars has been extensively studied …