Structural Biology Commons^™

Helical Remodeling Augments 5-Lipoxygenase Activity In The Synthesis Of Proinflammatory Mediators, Eden M. Gallegos, Tanner D. Reed, Forge A. Mathes, Nelson V. Guevara, David B. Neau, Wei Huang, Marcia E. Newcomer, Nathaniel C. Gilbert

School of Medicine Faculty Publications

The synthesis of proinflammatory leukotrienes implicated in asthma, allergic rhinitis, and atherosclerosis is initiated by the enzyme 5-lipoxygenase (5-LOX). The crystal structure of human Stable-5-LOX revealed a conformation where the catalytic iron was inaccessible to bulk solvent as two aromatic residues on a conserved helix-α2 (Hα2) plugged the substrate access portal. Whether 5-LOX can also adopt a more open conformation has not been resolved. Here, we present a new conformation of 5-LOX where Hα2 adopts an elongated conformation equivalent to that described in other animal lipoxygenase structures. Our observation of the sigmoidal kinetic behavior of 5-LOX, which is indicative of …

Mtorc1 And Mtorc2 Complexes Regulate The Untargeted Metabolomics And Amino Acid Metabolites Profile Through Mitochondrial Bioenergetic Functions In Pancreatic Beta Cells, Ghada A. Soliman, Rinat Abzalimov, Ye He

Advanced Science Research Center

Background: Pancreatic beta cells regulate bioenergetics efficiency and secret insulin in response to glucose and nutrient availability. The mechanistic Target of Rapamycin (mTOR) network orchestrates pancreatic progenitor cell growth and metabolism by nucleating two complexes, mTORC1 and mTORC2. Objective: To determine the impact of mTORC1/mTORC2 inhibition on amino acid metabolism in mouse pancreatic beta cells (Beta-TC-6 cells, ATCC-CRL-11506) using high-resolution metabolomics (HRM) and live-mitochondrial functions. Methods: Pancreatic beta TC-6 cells were incubated for 24 h with either: RapaLink-1 (RL); Torin-2 (T); rapamycin (R); metformin (M); a combination of RapaLink-1 and metformin (RLM); Torin-2 and metformin (TM); compared to the control. …

Modulation Of Kras Structure And Dynamics By Kras Ubiquitination And Membrane Depolarization, Vinay Nair

Dissertations and Theses (Open Access)

KRAS, a 21 kDa small GTPase protein, functions as a molecular switch playing a key role in regulating cell proliferation. Dysregulation of KRAS signaling by oncogenic mutations leads to uncontrolled cell proliferation, a hallmark of cancer cells. Attempts to therapeutically target oncogenic KRAS have led to limited success resulting in a need to identify new mechanisms to targeting KRAS. The interaction of KRAS with its regulators, effectors, and the membrane present one such avenue. In this study, we investigated how post-translational covalent and environmental modifications could modulate these interactions of KRAS. Using computational molecular dynamics simulations, nuclear magnetic resonance spectroscopy …

The Development Of Inhibitors For Sars-Cov-2 Orf8, My Thanh Thao Nguyen

CSB and SJU Distinguished Thesis

An unexpected outbreak of SARS-CoV-2 caused a worldwide pandemic in 2020. Many repurposed drugs were tested, but there are currently only three FDA approved antivirals (Merck’s antiviral Molnupiravir, Pfizer’s antiviral Paxlovid, and Remdisivir).1 Most of the antiviral drugs tested SARS-CoV-2 main protease and RNA-dependent RNA polymerase. However, it is important to explore different drug targets of SARS-CoV-2 to prepare for the virus mutations of the future. This research looks at an alternative approach in which SARSCoV- 2 Open Reading Frame 8 (ORF8), which has been shown to be a rapidly evolving hypervariable gene, was chosen to be the protein of …

Sars-Cov-2 Main Protease Inhibitors Repurposed For Hiv-1 Protease Binding, Jacob Minkkinen

CSB and SJU Distinguished Thesis

Severe acute respiratory syndrome (SARS-CoV-2) led to the COVID-19 global pandemic, with over 460 million cases of infection and over 6 million deaths since the start of the pandemic. SARS-CoV-2 is a retrovirus that utilizes a main protease (Mpro). Mpro is a catalytic cys/his protease. Several treatments were proposed to stop the pandemic including repurposing drugs to inhibit the Mpro. Another retrovirus that uses a protease is human immunodeficiency virus (HIV-1) which has been a global epidemic for 40 years and is a devastating disease that attacks the immune system. HIV-1 has infected 79.5 million people and has killed an …

Building Tools For Improved Modulation Of The Human Gabaa Receptor, A Central Nervous System Target For The Treatment Of Anxiety, Garrett Edward Zinck

Theses and Dissertations--Pharmacy

In the U.S., anxiety is recognized as an increasing range of mentally and physically debilitating psychiatric health disorders with significant economic repercussions. Over the last 20 years, several novel anti-anxiety therapies have entered the drug development pipeline, but none have made it to market.

The work in this dissertation focused on structurally modifying valerenic acid (VA), a structurally unique carboxylated sesquiterpene acid found in Valeriana officinalis. VA is putatively reported to have allosteric modulatory activity of the human GABA_A receptor, a ligand-gated ion channel responsible for attenuating neurotransmissions. Structural modeling of VA’s GABA_A receptor interaction suggests that …

Structure-Based Drug Discovery And Development Of Protein Structure Prediction Tools Using An Empirical Force Field, Noah B. Herrington

Theses and Dissertations

Traditional drug discovery has rapidly accelerated thanks to development of computational molecular modeling. The crucial component that these computational studies hinge upon is having a well-defined, and energetically favorable structure. Structures of proteins and ligands that meet these criteria are important for accurately simulating models used to study drug binding. To demonstrate the role of accurate structure simulation in the study of these events, this thesis presents, first, a story examining the problem of accurate structure modeling of ionizable residues within protein structures, specifically aspartic acid, glutamic acid, and histidine. I present our method, which uses the HINT force field …

Protein Structure And Interaction: The Role Of Aromatic Residues In Protein Structure And Interactions Between Pyridoxine 5'-Phosphate Oxidase/Dopa Decarboxylase, Mohammed H. Al Mughram

Theses and Dissertations

Naturally developed proteins are capable of carrying out a wide variety of molecular functions due to their highly precise three-dimensional structures, which are determined by their genetically encoded sequences of amino acids. A thorough knowledge of protein structures and interactions at the atomic level will enable researchers to get a deep foundational understanding of the molecular interactions and enzymatic processes required for cells, resulting in more effective therapeutic interventions. This dissertation intends to use structural knowledge from solved protein structures for two distinct objectives.

In the first project, we conducted a bioinformatics structural analysis of experimental protein structures using our …

Ero1Α Promotes Tumorigenesis In Egfr Driven Nsclc, Brennan D. Johnson

Graduate Theses, Dissertations, and Problem Reports (ETD)

Non-Small Cell Lung Cancer (NSCLC) is a pulmonary malignancy most commonly associated with smoking, or exposure to asbestos or Radon. Approximately, 1.6 Million deaths occur each year due to lung cancer. Lung Cancer is categorized by two main types, Small Cell Lung Cancer (SCLC) and NSCLC. NSCLC accounts for approximately 85% of all lung cancer cases and is subdivided into three sub-categories: Adenocarcinoma, the most common and leading cause of death in the United States; Squamous Cell Carcinoma (SCC), and Large Cell Carcinoma. Though NSCLC treatment regimens have shown increasing clinical benefit over the last two decades with targeted therapies. …

An Empirical Pipeline For Personalized Diagnosis Of Lafora Disease Mutations, M. Kathryn Brewer, Maria Machio-Castello, Rosa Viana, Jeremiah L. Wayne, Andrea Kuchtová, Zoe R. Simmons, Sarah Sternbach, Sheng Li, Maria Adelaida García-Gimeno, Jose M. Serratosa, Pascual Sanz, Craig W. Vander Kooi, Matthew S. Gentry

Molecular and Cellular Biochemistry Faculty Publications

Lafora disease (LD) is a fatal childhood dementia characterized by progressive myoclonic epilepsy manifesting in the teenage years, rapid neurological decline, and death typically within ten years of onset. Mutations in either EPM2A, encoding the glycogen phosphatase laforin, or EPM2B, encoding the E3 ligase malin, cause LD. Whole exome sequencing has revealed many EPM2A variants associated with late-onset or slower disease progression. We established an empirical pipeline for characterizing the functional consequences of laforin missense mutations in vitro using complementary biochemical approaches. Analysis of 26 mutations revealed distinct functional classes associated with different outcomes that were supported by clinical …

Alterations To The Brain Following Traumatic Brain Injury, Jacqueline Mader

Honors Projects

Traumatic brain injuries (TBIs) have been labeled as a modern-day epidemic, increasing exponentially with the advancement of technology and society. Gaining a better understanding of the cognitive paths, including the chemical and electrical signals of the brain, neural correlates, and possible interventions for TBI patients allows for the best possible outcome for every patient, and allows for the further advancement of care. By revising and reassessing the ways in which TBIs are categorized and described the prognosis for recovery paints a more realistic view for each individual patient case. The symptoms and impairments that may occur post-injury can be monitored …

The Structural And Functional Role Of Photosensing In Rgs-Lov Proteins, Zaynab Jaber

Dissertations, Theses, and Capstone Projects

Light provides organisms with energy and spatiotemporal information. To survive and adapt, organisms have developed the ability to sense light to drive biochemical effects that underlie vision, entrainment of circadian rhythm, stress response, virulence, and many other important molecularly driven responses. Blue-light sensing Light-Oxygen-Voltage (LOV) domains are ubiquitous across multiple kingdoms of life and modulate various physiological events via diverse effector domains. Using a small molecule flavin chromophore, the LOV domain undergoes light-dependent structural changes leading to activation or repression of these catalytic and non-catalytic effectors. In silico analyses of high-throughput genomic sequencing data has led to the marked expansion …

Anatomy And Physiology Preparatory Course Textbook (2nd Edition), Carlos Liachovitzky

Open Educational Resources

The goal of this preparatory textbook is to give students a chance to become familiar with some terms and some basic concepts they will find later on in the Anatomy and Physiology course, especially during the first few weeks of the course.

Organization and functioning of the human organism are generally presented starting from the simplest building blocks, and then moving into levels of increasing complexity. This textbook follows the same presentation. It begins introducing the concept of homeostasis, then covers the chemical level, and later on a basic introduction to cellular level, organ level, and organ system level. This …

Unveiling Global Roles Of G-Quadruplexes And G4-22 In Human Genetics, Ruth Barros De Paula

Dissertations and Theses (Open Access)

G-quadruplexes are non-B DNA structures formed by four or more runs of repeated guanines that confer unique features to living organism’s genomes. These sequences are enriched in regulatory regions, such as promoters and 5’ UTRs, and have distinct regulatory roles in both health and disease states. Even though previous studies showed the impact of G4 in gene expression, none of them summarized the location-specific effect of G4. Also, there is no broad understanding about the most common G4 repeat in the human genome, named here as G4-22, and how it links to the evolution of mammals and their biology. In …

Search For Palladin, An Actin-Associated Protein, In Pig Retinal Pigmented Epithelium And Its Role In Epithelial-Mesenchymal Transition, Katrina Powell

Undergraduate Theses

This study investigates the expression of Palladin, a phosphoprotein product of the PALLD gene, in the retinal pigmented epithelium (RPE). Palladin is an actin cross-linking protein and plays a role in cell adhesion and motility. Published reports have demonstrated that a down regulation of Palladin in colon cancer cells results in a reorganization of the actin cytoskeleton, causing the cells to lose their typical shape, become proliferative and migratory. This process is otherwise known as epithelial-mesenchymal transition (EMT). A similar EMT phenomenon is observed when the RPE is exposed to the vitreous humor in patients with proliferative vitreoretinopathy (PVR). In …

Fundamental Causes Of Racial And Ethnic Covid-19-Related Health Disparities, Hana Neutz

Student Scholar Symposium Abstracts and Posters

Underserved low-income communities of color in the U.S. have endured an unequal burden of COVID-19 morbidity and mortality. This pattern of pandemic-related health disparities has been pervasive throughout history. However, no known studies have simultaneously examined social and biological factors that contribute to these concerning health disparities. Therefore, this paper aims to bridge the gap by employing a scoping literature review of (1) the deleterious impacts of systemic racism on COVID-19-related outcomes; and (2) the cellular and molecular mechanisms connecting COVID-19 and hypertension (a comorbidity known to exacerbate COVID-19 severity). My findings indicate that systemic racism manifests in inequitable access …

Mitochondrial Distribution Of Glycine Receptors In Motor Neuron Cell Lines, Katsiaryna Milashevich

Student Theses and Dissertations

Although non-essential, glycine plays an important role in major metabolic reactions and is most known for its anti-inflammatory effects. An accumulation of contemporary research has shown that glycine is able to stabilize membrane potential using glycine receptors at the cellular level and to protect mitochondrial function directly, whether it is from inflammation, heavy metal poisoning, or ischemia-induced neuroinflammation. In this research, the existence of a hypothetical mitochondrial glycine receptor is examined. Immunofluorescence imaging was used to examine the presence of the glycine receptor subunits alpha 1 and alpha 2 in both non- differentiated and differentiated neuroblastoma cell lines. The preliminary …

'Induction Of Apoptosis, Cytotoxicity And Radiosensitization By Novel 3,4-Dihydroquinazolinone Derivatives, Eman Ramadan, Amira Khalil

Pharmacy

Twenty new quinazolinone derivatives bearing a piperonyl moiety were designed and synthesized. The structures of the target compounds were in agreement with the microanalytical and spectral data. Compounds 4-10, 13, 14 and 17-27 were screened for their cytotoxic activity against HepG-2 and MCF-7 cancer cell lines. The target compounds showed IC₅₀ in the range of 2.46-36.85 µM and 3.87-88.93 µM for HepG-2 and MCF-7, respectively. The promising compounds 7, 19, 26 and 27 were selected to measure their EGFR inhibitory activity. The IC₅₀ values of the promising compounds were in the range of 146.9-1032.7 nM for EGFR in …

Applied Molecular Dynamics: From Targeting Viral Helicases, To Understanding The Interactions Of Cucurbituril Complexes In Ionic Solutions, Bryan Raubenolt

LSU New Orleans Theses and Dissertations

Molecular Dynamics simulations are a highly useful tool in helping understand the fundamental interactions present in a variety of chemical systems. The work discussed here illustrates it’s use in determining the conformational dynamics of the Zika and SARS-Cov-2 helicase in a physiological environment, largely in an effort to discover inhibitors capable of rendering the protein inert. Additionally, we show how it can be used to understand paradoxical trends in the anion-induced precipitation of Cucurbituril cavitands.

Viral helicases are motor proteins tasked with unwinding the viral dsRNA, a crucial step in preparing the strand to be translatable by host cells. By …

Development Of Computational To Ols To Target Microrna, Luo Song

Dissertations and Theses (Open Access)

MicroRNAs (a.k.a, miRNAs) play an important role in disease development. However, few of their structures have been determined and structure-based computational methods remain challenging in accurately predicting their interactions with small molecules. To address this issue, my thesis is to develop integrated approaches to screening for novel inhibitors by targeting specific structure motifs in miRNAs. The project starts with implementing a tool to find potential miRNA targets with desired motifs. I combined both sequence information of miRNAs and known RNA structure data from Protein Data Bank (PDB) to predict the miRNA structure and identify the motif to target, then I …

Functional Analysis Of A Critical Glycine (Glycine 12) In Beta-Type Connexins Of Human Skin, Rasheed Bailey

Biology Theses

At least five beta-type connexins are expressed in various layers of the skin (Cx26, Cx30, Cx30.3, Cx31, and Cx32) and all include a glycine residue at position 12. Glycine12 (G12) is located about halfway through the cytoplasmic amino terminus and has been the focus of several studies related to connexin diseases and gap junction channel structure. The importance of this residue is evident in the severity and diversity of diseases associated with amino acid substitutions at G12 including hereditary forms of skin disease, deafness and neuropathy. This study uses bioinformatic analysis in combination with mutational analysis and electrophysiology to better …

Characterization Of The Nuclear Pore Complex In Red Alga, Cyanidioschyzon Merolae, Michelle Veronin

Health and Kinesiology Theses

Cyanidioschyzon merolae (C. merolae) is a primitive, unicellular species of red alga that is considered to be one of the simplest self-sustaining eukaryotes. The highly elementary nature of C. merolae makes it an excellent model organism for studying evolution as well as cell function and organelle communication. In our study, we hypothesize that C. merolae contains the minimal assembly of proteins to make up their Nuclear Pore Complexes (NPCs), and hence are the first ancestral NPCs. NPCs are essential for basic nuclear transport in the cell. They are embedded in the double membrane of the nucleus, the …

Single Molecule Fluorescence Studies Of Protein Structure And Dynamics Underlying The Chloroplast Signal Recognition Particle Targeting Pathway, Dustin R. Baucom

Graduate Theses and Dissertations

The work presented in this dissertation explores the structural dynamics in the chloroplast signal recognition particle pathway. Findings include cpSRP shows scanning functionality similar to that in the cytosolic SRP with the ribosome. The intrinsically disordered C-terminal tail of the Albino3 protein has some transient secondary structure. Upon binding to cpSRP43 in solution, separate secondary structure formation was identified in the C-terminal tail of Albino3. Finally, to increase efficiency of analyzing fluorescence time traces for this work, a modular software was produced.

Influence Of Single And Multiple Histidine Residues And Their Ionization Properties On Transmembrane Helix Dynamics, Orientations And Fraying, Fahmida Afrose

Graduate Theses and Dissertations

Since aromatic and charged residues are often present in various locations of transmembrane helices of integral membrane proteins, their impacts on the molecular properties of transmembrane proteins and their interactions with lipids are of particular interest in many studies. In this work, I used solid-state deuterium NMR spectroscopy in designed model peptide GWALP23 [GGALW(LA)6LWLAGA] with selective deuterium labels to addresses the pH dependence and influence of single and multiple “guest” histidine residues in the orientation and dynamic behaviors of transmembrane proteins. The mutations include Gly to His (G2/22 to H2/22), Trp to His (W5/19 to H5/19) and Leu to His …

Effective Statistical Energy Function Based Protein Un/Structure Prediction, Avdesh Mishra

LSU New Orleans Theses and Dissertations

Proteins are an important component of living organisms, composed of one or more polypeptide chains, each containing hundreds or even thousands of amino acids of 20 standard types. The structure of a protein from the sequence determines crucial functions of proteins such as initiating metabolic reactions, DNA replication, cell signaling, and transporting molecules. In the past, proteins were considered to always have a well-defined stable shape (structured proteins), however, it has recently been shown that there exist intrinsically disordered proteins (IDPs), which lack a fixed or ordered 3D structure, have dynamic characteristics and therefore, exist in multiple states. Based on …

Development Of A Sonically Powered Biodegradable Nanogenerator For Bone Regeneration, Avi Patel

Honors Scholar Theses

Background: Reconstruction of bone fractures and defects remains a big challenge in orthopedic surgery. While regenerative engineering has advanced the field greatly using a combination of biomaterial scaffolds and stem cells, one matter of difficulty is inducing osteogenesis in these cells. Recent works have shown electricity’s ability to promote osteogenesis in stem cell lines when seeded in bone scaffolds; however, typical electrical stimulators are either (a) externally housed and require overcomplex percutaneous wires be connected to the implanted scaffold or (b) implanted non-degradable devices which contain toxic batteries and require invasive removal surgeries.

Objective: Here, we establish a biodegradable, piezoelectric …

Incorporation Of Egfr And Ron Receptors Into Nanodiscs, Cristina Flores-Cadengo

Biomedical Engineering ETDs

Understanding the structure-function relationship of membrane receptors is essential to comprehend the crosstalk between key signaling pathways. Aberrant trans-activation between receptors can lead to tumorigenesis. Two of these receptors known to be involved in cancer development are receptor tyrosine kinases (RTKs), RON (Recepteur d'Origine Nantais) and EGFR (Epidermal Growth Factor Receptor). There has been evidence of heterodimerization and crosstalk between these two receptors based on co-immunoprecipitation, however the structural requirements behind these interactions remain unknown. Structural studies could provide insights into these RTKs’ modes of dimerization and structure-function relationship. However, structural studies of full-length membrane proteins are often difficult due …

Method Development For Structural Assessment Of Nanolipoprotein Particles With And Without Cross-Linked Lipids, Emma J. Mullen, Wei He, Sean Gilmore, Matthias Frank, Matthew Coleman, Megan Shelby

STAR Program Research Presentations

Membrane proteins make up approximately 30% of the cellular proteome and account for over 60% of pharmaceutical targets.1 Determining the structures of this class of proteins is critical to our understanding of disease states and will advance rational drug design. But membrane proteins have limited solubility, rarely form large crystals that diffract well, and often misfold outside of a bilayer, hindering crystallographic studies.1 Nanolipoprotein particles (NLPs) have arisen as a platform to readily solubilize membrane proteins while mimicking a native lipid environment. NLPs consist of a discoidal phospholipid bilayer encircled by an apolipoprotein belt. In an effort to optimize and …

Toward An Enzyme-Coupled, Bioorthogonal Platform For Methyltransferases: Probing The Specificity Of Methionine Adenosyltransferases, Tyler D. Huber

Theses and Dissertations--Pharmacy

Methyl group transfer from S-adenosyl-l-methionine (AdoMet) to various substrates including DNA, proteins, and natural products (NPs), is accomplished by methyltransferases (MTs). Analogs of AdoMet, bearing an alternative S-alkyl group can be exploited, in the context of an array of wild-type MT-catalyzed reactions, to differentially alkylate DNA, proteins, and NPs. This technology provides a means to elucidate MT targets by the MT-mediated installation of chemoselective handles from AdoMet analogs to biologically relevant molecules and affords researchers a fresh route to diversify NP scaffolds by permitting the differential alkylation of chemical sites vulnerable to NP MTs that are unreactive to …

The N-Terminal Methyltransferase Homologs Nrmt1 And Nrmt2 Exhibit Novel Regulation Of Activity Through Heterotrimer Formation., Jon David Faughn

Electronic Theses and Dissertations

Protein, DNA, and RNA methyltransferases have an ever-expanding list of novel substrates and catalytic activities. Even within families and between homologs, it is becoming clear the intricacies of methyltransferase specificity and regulation are far more diverse than originally thought. In addition to specific substrates and distinct methylation levels, methyltransferase activity can be altered through formation of complexes with close homologs. This work involves the N-terminal methyltransferase homologs NRMT1 and NRMT2. NRMT1 is a ubiquitously expressed distributive trimethylase. NRMT2 is a monomethylase expressed at low levels and in a tissue-specific manner. They are both nuclear methyltransferases with overlapping target consensus sequences …