Structural Biology Commons^™

Optimization And Standardization Of Dms Chemical Mapping Experiments For Probing Rna 3d Structure, Sarah Brady

Honors Program: Senior Projects (Public)

RNA plays a significant and crucial role in biological processes. The properties of RNA are ultimately responsible for each molecule’s unique function. The configuration and structural integrity of RNA is important for its functionality. Chemical mapping detailed in this thesis can be used to analyze the 3D structure of an RNA sequence. RNA is modified via methylation of adenine and cytosine bases using dimethyl sulfate, then reverse transcribed to DNA, then sequenced. The sites where the bases were methylated become mutations in the DNA sequence, allowing for identification of these locations when analyzing sequencing data. Conditions for modification can be …

Mimicking The Namib Desert Beetle With Hydrophilic And Hydrophobic Surfaces, Tyler Bracewell

Williams Honors College, Honors Research Projects

The Namib Desert beetle, Stenocara gracilipes, condenses fog that rolls in off the west coast of Namibia to provide itself with the water it needs for the day. By lifting its abdomen into the air to collect the water vapor, it condenses on hydrophilic bumps that are about 500μm in diameter and are spaced apart about 500-1500μm. Once the water reaches a critical size, the droplet rolls off the hydrophilic bump and onto the flat hydrophobic surface of the elytra. Since the beetle is angled with its abdomen in the air, the water rolls down to its mouth. A …

Structural Basis For Reversible Glucan Phosphorylation By Glucan Dikinases And Glucan Phosphatases, Tiantian Chen

Theses and Dissertations--Molecular and Cellular Biochemistry

Plants store glucose in the form of starch, an insoluble macromolecule that is synthesized and degraded diurnally. Glucan phosphatases play a critical role in starch breakdown, working with glucan dikinases in a cyclic phosphorylation and dephosphorylation. Herein, we present a novel glucan phosphatase Like SEX Four3 (LSF3) from Physcomitrella patens. Structural and enzymatic studies demonstrate that LSF3 is a dimeric glucan phosphatase that displays robust specific glucan phosphatase activity. Dimerization is shown to be essential for LSF3 stability and function. Structure-guided bioinformatic analysis shows that LSF3 is found in early land plants and green algae.

Building upon our understanding of …

Elucidating The Proteasomal Regulatory Mechanism Of Proteasome Activator Pa28Γ /Regγ, Taylor Ann Thomas

Graduate Theses, Dissertations, and Problem Reports (ETD)

Virtually all cellular processes are precisely regulated by the proteasome which is the primary enzyme responsible for the degradation of misfolded, damaged, or no longer necessary soluble proteins. To prevent any untimely degradation of these target protein substrates and protect the cell, the proteasome is tightly regulated via adaptor proteins, known as proteasomal regulators. There are many classes of proteasomal regulators each with their own unique structures, functions, and effects on protein degradation through the proteasome. One such class is the 11S family of proteasomal regulators which are also referred to as PA26/28, or REG. The 11S family are ATP-independent …

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. …

The Role Of Charge On Dna Packaging And Integrity Within Reconstituted Peptide-Dna Assemblies, Ehigbai Oikeh

Theses and Dissertations--Chemistry

In nature, DNA exists primarily in a highly compacted form. The compaction of DNA in vivo is mediated by cationic proteins; histone in somatic nuclei and arginine-rich peptides called protamines in sperm chromatin. The packaging in the sperm nucleus is significantly higher than somatic nuclei resulting in a final volume roughly 1/20^th that of a somatic nucleus. This tight packaging results in a near crystalline packaging of the DNA helices. While the dense packaging of DNA in sperm nuclei is considered essential for both efficient genetic delivery as well as DNA protection against damage by mutagens and oxidative species, …

Cryo-Em Structure Of Transmembrane Aaa+ Protease Ftsh In The Adp State, Wu Liu, Martien Schoonen, Tong Wang, Sean Mcsweeney, Qun Liu

Advanced Science Research Center

AAA+ proteases regulate numerous physiological and cellular processes through tightly regulated proteolytic cleavage of protein substrates driven by ATP hydrolysis. FtsH is the only known family of membrane-anchored AAA+ proteases essential for membrane protein quality control. Although a spiral staircase rotation mechanism for substrate translocation across the FtsH pore has been proposed, the detailed conformational changes among various states have not been clear due to absence of FtsH structures in these states. We report here the cryo-EM structure for Thermotoga maritima FtsH (TmFtsH) in a fully ADP-bound symmetric state. Comparisons of the ADP-state structure with its apo-state and a substrate-engaged …

Expression And Purification Of Cytochrome 2u1 And Canine 1a2 And Metabolism Of Caffeine By Cytochrome 1a2, Brenda M. Wekesa

Graduate Theses/Dissertations

Cytochrome P450 enzymes are a large family of membrane heme proteins involved in eliminating drugs and the synthesis or elimination of steroids, eicosanoids, and vitamins. CYP2U1 is one of the poorly characterized P450 enzymes classified as orphan cytochrome P450 with unknown exact biological function. It is expressed in the brain and thymus as a catalyst in the hydroxylation of arachidonic acid. Unlike other cytochrome P450s, CYP2U1 is a bit unusual with forty extra amino acids. If a mutation occurs, it can lead to an early onset inherited disorder of the central nervous system called Hereditary Spastic Paraplegias (HSP). Most of …

Snake Venom Peptides And Toxin Targeting The Main Protease Of Sars-Cov-2, Breauna Strawder, James Stewart, Mohammad A. Halim

Symposium of Student Scholars

The corona virus began to spread in Wuhan, China which caused it to spread worldwide creating a global pandemic in the beginning of 2020, infecting over 243 million and killing over 4.5 million people worldwide. Significant efforts were made to produce vaccines against the virus, which led the recognition of a few vaccines that has been approved by FDA. These vaccines, Pfizer-BioNTech, Moderna and Johnson & Johnson, which all have efficacy against Covid-19. Despite having vaccines, COVID-19 is still present and infecting millions and killing thousands of people every day. Multiple therapeutic options would allow us to slow down or …

Binding Affinity And Interaction Of Sars-Cov-2 Epitopes With Major Histocompatibility Complex, Sareena Kandavalli, James Stewart, Mohammed A. Halim

Symposium of Student Scholars

SARS CoV-2 has been affecting the world since 2019. It caused 245 million cases of infection and around 5 million deaths worldwide. The most important strategies for the development of vaccines against SARS-CoV-2 are inactivated or weakened virus, replicating or non-replicating viral vector-based approaches, DNA, RNA, virus particle like approaches and epitope-based approaches. The epitope-based approach is rapid, accurate, cost-effective, and reliable against pathogens. By presenting epitopes (antigen peptides) on antigen-presenting cells (APCs), the major histocompatibility complex (MHC), also recognized as the human leukocyte antigen (HLA) system in humans, plays an essential role in triggering T-cell immune responses. The focus …

3-Dimensional Structural Determination Of Epidermal Growth Factor-Like Repeat 27 From Mouse Notch1 Using Nuclear Magnetic Resonance Spectroscopy, Justin Grennell

LSU Doctoral Dissertations

NOTCH1 has been associated with a variety of human ailments, such as cancer and heart disease. NOTCH1 is a transmembrane protein that contains 36 epidermal growth factor-like (EGF) repeats, which facilitate cell signaling by binding proteins on neighboring cells. Each repeat contains about 40 amino acids and has to be folded in a specific manner to function properly. The amino acid sequence, carbohydrate pattern, and calcium-binding sites of EGF-like repeats vary, but the pattern along the 36-repeat chain is conserved. The Abruptex region (EGF24-29) of NOTCH1 is a highly glycosylated (having undergone sugar addition) and flexible region, which gained its …

Cryo-Em Structure Of Mechanosensitive Channel Ynai Using Sma2000: Challenges And Opportunities, Claudio Catalano, Danya Ben-Hail, Weihua Qiu, Paul Blount, Amedee Des Georges, Youzhong Guo

Publications and Research

Mechanosensitive channels respond to mechanical forces exerted on the cell membrane and play vital roles in regulating the chemical equilibrium within cells and their environment. Highresolution structural information is required to understand the gating mechanisms of mechanosensitive channels. Protein-lipid interactions are essential for the structural and functional integrity of mechanosensitive channels, but detergents cannot maintain the crucial native lipid environment for purified mechanosensitive channels. Recently, detergent-free systems have emerged as alternatives for membrane protein structural biology. This report shows that while membrane-active polymer, SMA2000, could retain some native cell membrane lipids on the transmembrane domain of the mechanosensitive-like YnaI channel, …

A Nosy Neighbor: Purification And Functional Characterization Of Lpg2149, Ashley M. Holahan

The Journal of Purdue Undergraduate Research

Ubiquitination is a process that marks proteins for various cell-signaling pathways, namely protein degradation and other processes. Th ese pathways are essential in a wide array of cellular processes, including defense mechanisms against invading pathogens. Th e ubiquitination process is universally found in all eukaryotic organisms, including plants and animals, and thus plays a vital role in cellular homeostasis. Recently, more discoveries have been made on prokaryotic effector proteins that hijack the ubiquitination system even when they do not possess a ubiquitin system of their own. MavC, also known as lpg2147 (Gan, Nakayasu, Hollenbeck, & Luo, 2019; Puvar et al., …

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 …

Determining The Primary Dna Substrates Of Shld2'S Ob-Fold Domains, Hari Patchigolla

Holster Scholar Projects

Failure to repair DNA double-stranded breaks leads to cell death. Radiation therapy is commonly used to kill cancer cells by inducing these breaks. However resistance to radiation therapy, due to a hyperactive DNA double-stranded break repair pathway, is a common occurrence that makes cancer patients more prone to relapse. The Shieldin complex is shown to promote DNA-double stranded break repair by binding to DNA at sites of damage. Thus, the objective of this project is to understand the affinity and type of DNA that Shieldin binds to, through gel-shift assays, for the eventual creation of an inhibitor for this protein …

Analysis Of Single-Site Cysteine Mutation, I412c, In Human A Glycine Receptor States To Further Refine Structure And Allostery, Leah Engquist

Honors Program: Senior Projects (Public)

The glycine receptor (GlyR) is the major inhibitory receptor in the brain and spinal cord. A member of the pentameric ligand gated ion channel superfamily, crystal structures are available but there are still unresolved areas, specifically the C-terminal tail and TM3-TM4 intracellular loop. Further refinement can provide deeper understanding of the molecular mechanism and allow the creation of novel therapeutics to modulate its function. We propose to insert a single cysteine mutation, I412C, into a Cys null background (C41S/C290A/C345S) to study non- conducting states (resting, desensitized) or with F207G/A288G mutations to study the open state. Purified, reconstituted GlyR is crosslinked …

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 …

Covid-19 In Silico Drug With Zingiber Officinale Natural Product Compound Library Targeting The Mpro Protein, Renadya Maulani Wijaya, Muhammad Aldino Hafidzhah, Viol Dhea Kharisma, Arif Nur Muhammad Ansori, Arli Aditya Parikesit

Makara Journal of Science

Coronavirus disease 2019 (COVID-19), which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a worldwide pandemic. Ginger (Zingiber officinale) is a rhizome, which is commonly used for culinary and medicinal purposes. In Indonesia, ginger is taken as traditional medicine by processing it into a drink known as jamu. The present study aimed to assess and evaluate the bioactive compounds in ginger that can be used in drug design for treating COVID-19. The crystal structure of the SARS-CoV-2 main protease (M^pro) was generated from a protein sequence database, i.e., Protein Data Bank, …

Conformation Of The Protein-Free Spliceosomal U2-U6 Snrna Complex And Remodeling By Mg2+ And Proteins, Huong Chu

Dissertations, Theses, and Capstone Projects

Splicing of precursor messenger RNA is an essential process in eukaryotes in which the non-coding regions (introns) are removed and coding regions (exons) ligated together to form a mature mRNA. This process is catalyzed by a multi-mega Dalton ribonucleoprotein complex called the spliceosome, which is assembled from five small nuclear ribonucleoproteins (snRNP) in the form of RNA-protein complexes (U1, U2, U4, U5 and U6) and hundreds of proteins. U2 and U6 small nuclear (sn)RNAs are the only snRNAs directly implicated in catalyzing the splicing of pre-mRNA, but assembly and rearrangement steps prior to catalysis require numerous proteins. Previous studies have …

Machine Learning And Solvation Theory For Drug Discovery, Lieyang Chen

Dissertations, Theses, and Capstone Projects

Drug discovery is a notoriously expensive and time-consuming process; hence, developing computational methods to facilitate the discovery process and lower the associated costs is a long-sought goal of computational chemists. Protein-ligand binding, which provides the physical and chemical basis for the mechanism of action of most drugs, occurs in an aqueous environment, and binding affinity is determined not only by atomic interactions between the protein and ligand but also by changes in their interactions with surrounding water molecules that occur upon binding. Thus, a quantitative understanding of the roles water molecules play in the protein-ligand binding process is an essential …