Structural Biology Commons^™

Biochemical And Structural Insights Into The Yersinia Effector Yopm And Its Negative Regulation Of The Pyrin Inflammasome, Bethany Wairimu Mwaura

Dartmouth College Ph.D Dissertations

Bacteria utilize sophisticated secretion systems to inject effectors into host cells in order to facilitate their survival and replication in the host. Some pathogenic species of Gram-negative bacteria use a conserved contact-dependent T3SS to inject a wide array of effectors. While the effectors diverge in their structures, functions and cell-localization, the T3SS is well conserved. Several effectors discussed in this thesis target key host inflammasome responses. The focus of this work is how the Yersinia effector YopM inhibits the pyrin inflammasome. During Yersinia infection, two effectors, YopE and YopT inadvertently activate the pyrin inflammasome while targeting RhoA to avoid phagocytosis. …

Toward Ar Visualization Of The Fluid-Mosaic Model Of The Cell Membrane, Yoonwoo Lee, Allison Ost, Junghyuk Lee, Krisztina Z. Bencze

SACAD: Scholarly Activities

Background: During the first semester of biochemistry experience, students focus on learning the structure and function of biomolecules: carbohydrates, lipids, proteins, and nucleic acids. Visualizing these structures and understanding interactions between molecules helps students better understand biological function. A variety 3D visualization tools are available, ex. PyMol, Chimera, Avogadro, Blender. Within the past decade, Augmented Reality (AR) and Virtual Reality (VR) applications gained more popularity. VR with its immersive visual experience is more sought-after, but the higher cost and the need for headset creates limitations in the classroom. AR visualizations are cheaper and more accessible, several publications report successful implementation …

Induced Mutagenesis In West Nile Virus Non-Structural Protein 3 With A Discussion Of The Mutation's Effects On Viral Properties, Caden Connealy

Honors Program: Senior Projects (Public)

West Nile Virus (WNV), a member of the Flaviviridae family and introduced to the Western hemisphere in 1999, presents a unique and emerging threat to human health. Infection in humans is often mild but can occasionally result in severe neurological impairment and even death. West Nile Virus non-structural protein 3 (NS3) plays an important role in the process of viral genome amplification. More specifically, the C-terminal domain of the protein folds into a helicase enzyme, which is responsible for the “unwinding” of double-stranded RNA intermediates and RNA secondary structure on the WNV genome. This is a vitally important step in …

Bloom: Behavioral Learning And Outcome Observation In Microbes, Sean Sarwar Haque, Luke Compton Wharton, Ming Lin, Razvan Voicu

Symposium of Student Scholars

Understanding how pathogens respond to physical changes in their environment is crucial for developing effective treatments and preventative measures. Current research often relies on static models or experimental data that either fail to capture the dynamic interactions within cellular environments or are not generalizable to other types of pathogens. This project aims to address this gap by creating a comprehensive cell simulation that models pathogens and their response to chemical, physical, and physiological changes. The proposed solution is a simulation that integrates biological data and computational modeling to replicate the behavior of pathogens in real time as they are affected …

In-Silico Modeling And Characterization Of Kcc2 Protein Interaction With A Small Molecule Direct Agonist Identifies Potential Binding Sites For Modulating Behaviors Associated With Substances Of Abuse, William Hai Dang Ho, Alfred Amendolara, Kenyon Mitchell, Jaden Miner, Ruth Northcott, Braxton Bingham, Andrew J. Payne

Annual Research Symposium

Purpose

KCC2 is a potassium-chloride cotransporter that plays a critical role in neuronal function by regulating GABAergic signaling via chloride gradients. Maintaining this concentration gradient is crucial for balancing excitation and inhibition in the brain. While KCC2 dysregulation has been implicated in epilepsy and seizures, recent studies suggest that KCC2 inhibition results in phenotypes mirroring those seen in chronic opioid dependence. As such, increasing evidence support KCC2 being a potential therapeutic target for modulating behaviors associated with substances of abuse. Currently, only a few direct small molecule agonists against KCC2 have been reported, and no definitive active site on the …

Use Of Synthetic Water-Soluble Kcc2 To Modulate Chloride Homeostasis In Cultured Dopamine-Neuron-Like Cells, Mason Terry, Andrew Payne, Dario Mizrachi

Annual Research Symposium

No abstract provided.

Ivy Proteins As Guardians Of Bacterial Cell Wall Integrity: Regulation Of Lytic Transglycosylases Explored, Aamna Aijaz, Trinity E. Alamutu, Vy T. Dao, Nathaniel R. Davis, Michael D. Landers, Nykolas K. Mackevicius, Liliana Ortiz, Irina F. Padilla-Montoya, Kacy J. Smith, Maria L. Snyder, Anthony J. Stefanie, Blaise M. Williams, Thomas C. Leeper

The Kennesaw Journal of Undergraduate Research

Lytic transglycosylases (LTs) are bacterial enzymes involved in biosynthesis and maintenance of the peptidoglycan cell wall. LTs are reported to be regulated by two paralogs of Inhibitor of Vertebrate Lysozymes: Ivyp1 and Ivyp2. This study investigated the regulatory dynamics between the soluble LT (SltB1), and Ivy paralogs as putative regulators in Pseudomonas aeruginosa (PA). The secondary objective was to delineate the critical roles played by a glutamic acid at position 135 in SltB1 and a histidine at position 62 in Ivyp1 in governing their molecular interaction through site directed mutagenesis. Isolated SltB1 shows no lytic activity in our assay, in …

The Role Of Secondary And Tertiary Structure In The Cap-Independent Translation Of Fgf-9 And Hif-1-Alpha, Amanda Michelle Whittaker

Dissertations, Theses, and Capstone Projects

Under normoxic conditions, eukaryotes initiate translation of RNA through eIF4E recognition of the 5’ cap. However, under cellular stress, eukaryotic translation must be initiated through a 4E-independent, or “cap-independent” mechanism, involving eukaryotic initiation factor 4G (eIF4G) binding directly to the 5’ untranslated regions (5’ UTR) of the RNA. eIF4G binding then recruits the ribosome to the transcript. While this mechanism is useful for translation of apoptotic transcripts and transcripts involved in cell survival, cap-independent translation is also utilized by oncogenic RNA for tumorigenesis. Previous work by our lab and others has categorized this recruitment and initiation mechanism as either internal-ribosome-entry-site …

Fast 3d Printing Of Fine, Continuous, And Soft Fibers Via Embedded Solvent Exchange, Wonsik Eom, Mohammad Tanver Hossain, Vidush Parasramka, Jeongmin Kim, Ryan W. Y. Siu, Kate A. Sanders, Dakota Piorkowski, Andrew Lowe, Hyun Gi Koh, Michael F. L. De Volder, Douglas S. Fudge, Randy H. Ewoldt, Sameh H. Tawfick

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

Nature uses fibrous structures for sensing and structural functions as observed in hairs, whiskers, stereocilia, spider silks, and hagfish slime thread skeins. Here, we demonstrate multi-nozzle printing of 3D hair arrays having freeform trajectories at a very high rate, with fiber diameters as fine as 1.5 µm, continuous lengths reaching tens of centimeters, and a wide range of materials with elastic moduli from 5 MPa to 3500 MPa. This is achieved via 3D printing by rapid solvent exchange in high yield stress micro granular gel, leading to radial solidification of the extruded polymer filament at a rate of 2.33 μm/s. …

Characterizing And Targeting The Non-Catalytic Functions Of Phosphatase Of Regenerating Liver 3 (Prl-3) In Oncogenesis And Cancer Progression, Jeffery T. Jolly

Theses and Dissertations--Molecular and Cellular Biochemistry

Phosphatase of Regenerating Liver 3 (PRL-3) is frequently upregulated in various cancers and is associated with poor patient prognosis. Although traditionally studied for its phosphatase activity, PRL-3 also interacts with the CNNM family of magnesium transporters through its catalytic site, and these two functions are mutually exclusive at any given time. Most previous studies relied on a commonly used PRL-3 mutation that disrupts both phosphatase activity and CNNM binding, making it challenging to determine which function drives its oncogenic effects. To address this gap in the field, I utilized a panel of PRL-3 mutants that selectively disrupt either phosphatase activity …

Functional Analysis Of Ligand Binding Domain 2 Of Outer Surface Protein C Of Borreliella Burgdorferi, Gavin Z. Chambers

Theses and Dissertations

Lyme disease, caused by the spirochete Borreliella burgdorferi, is the most common vector-borne infection in North America. A critical determinant of early mammalian infection is outer surface protein C (OspC), a highly variable lipoprotein that is indispensable for spirochete survival but whose precise function remains unresolved. OspC has been proposed to mediate diverse roles, including complement evasion, adhesion, tissue dissemination, and antiphagocytic activity, supporting the view that it is a multifunctional virulence factor. Structural studies have identified two putative ligand-binding domains (LBD1 and LBD2), with LBD2 forming a solvent-exposed crown at the membrane-distal end of the OspC dimer.

To …

Reversible Degradation Of Peptidoglycan By Lytic Transglycosylases, Aaron Devereaux

Theses and Dissertations (Comprehensive)

Antimicrobial resistance continues to be a burden on the global healthcare system with an estimated cost of billions of dollars and millions of deaths each year. Recently, there has been little to no development on new antibiotics to treat bacterial infection, and any that are developed become resisted to within a few years. Both Gram-positive and Gram-negative bacteria contain a mesh-like layer called peptidoglycan (PG) that surrounds their cells providing strength, cell shape, and protection from their environments. This layer is a polymer of N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) connected via a b-1,4-glycosidic bond, with each strand being cross-linked …

Structural Insights Into Peptidoglycan O-Acetylation In Gram-Negative Bacteria, Tyler Malloch

Theses and Dissertations (Comprehensive)

The Centres for Disease Control has acknowledged that we are entering a post-antibiotic era, where increasing numbers of bacterial pathogens are becoming resistant to known antibiotics. One of the most successfully targeted features of bacteria is also the main component of the cell wall, peptidoglycan (PG). PG is a heteropolymer of alternating sugar residues, namely N-acetylmuramic acid (MurNAc) and N-acetylglucosamine (GlcNAc) which are joined together by b-(1,4)-glycosidic bonds and crosslinked via stem peptide chains. PG is a target, readily lysed by exogenous and endogenous autolysins, such as lysozyme and lytic transglycosylase, respectively. This event leads to cell death …

Development Of Cyan And Blue Thermostable Fluorescent Proteins: Characterization And Structural Analysis, Acacia J. Jurkowski

Graduate Theses/Dissertations

Fluorescent proteins are commonly used as cell markers in living organisms. Modifications by mutation can be used to improve the qualities of these proteins including fluorescence, thermostability, pH stability, and chemical stability. The goal of this project is to use mutagenesis to improve the fluorescence of thermostable cyan and blue proteins derived from the thermal green protein (TGP). The first cyan protein developed by the DeVore lab (CTP 0.0) shifted the fluorescence to cyan but decreased the quantum yield (Φ_F) to 0.056. Further mutations were incorporated to increase the quantum yield through incorporating hydrogen bonding interactions to the …

Bridging The Gap Between Structural And Cellular Biology: Insight Into The Organization Of Glycolytic Enzymes In Cells, Heather Hansen

Graduate Theses, Dissertations, and Problem Reports (ETD)

Glycolytic enzymes are spatially organized in the cytoplasm, and are shown to localize with cellular structures such as the plasma membrane, F-actin, mitochondria, or associate independently within the cytosol. The assembly of these enzymes is hypothesized to regulate pathway flux to meet the energetic needs of the cell. However, it is unclear whether all of these assemblies have the same mechanism of formation or function in the cell. We investigated the role of glycolytic enzyme assemblies in cells, using the glycolytic “gatekeeper” enzyme phosphofructokinase-1 (PFK1). PFK1 is extensively regulated by multiple mechanisms, including over 20 allosteric ligands, post translational modifications, …

Probing The 10-23 Dnazyme Catalytic Core: Insights From Structural And Mechanistic Studies, Evan Rhyse Cramer

Graduate Theses, Dissertations, and Problem Reports (ETD)

The 10-23 DNAzyme is a catalytically active DNA oligonucleotide capable of cleaving RNA at purine-pyrimidine junctions in the presence of divalent metal ions, most notably magnesium. Despite its promise as a programmable RNA knockdown tool, its clinical and biotechnical utility has been hampered by limited structural characterization, low catalytic efficiency under physiological conditions, and poor understanding of its in-cell activity. This dissertation presents a comprehensive framework for the structural and functional analysis of DNAzymes using the 10-23 DNAzyme as a model system. In the absence of high-resolution structures, we first employed detailed in vitro biochemical assays to map essential residues …

Characterization Of Adaptive Quorum Sensing In Pseudomonas Aeruginosa, Kayla Simanek

Electronic Theses & Dissertations (2024 - present)

Pseudomonas aeruginosa is an opportunistic pathogen that is highly antibiotic resistant and causes tens of thousands of infections each year. It persists in hospitals by forming biofilms on medical equipment like ventilators and catheters, making it difficult to eradicate. Biofilm formation, among other virulence factors of P. aeruginosa, is regulated through quorum sensing, a mechanism of bacterial communication. Quorum sensing is primarily coordinated through LuxI-R type systems comprised of an autoinducer synthase and receptor, respectively. Canonically, the first system to be expressed is LasI-R, and LasR upregulates the second arm of the quorum sensing network, the RhlI-R system. Research …

Technological Development Of In-Cell Nmr: Microfluidic, Metabolomic, And Fluxomic Approaches, Nicholas Sciolino

Electronic Theses & Dissertations (2024 - present)

In the fields of structural biology, metabolomics, and fluxomics, there is a driving, technique-based concern when it comes to high-resolution spectrometry and its marriage to biological and physiological relevance. Sample preparation often involves cellular perturbation, lysate separation schemes, combinations with non-biological reagents, and timeline slack. Conceptually, the farther we get from the cell, the greater the potential disparity between what exists in vivo and our in vitro manipulations. This is particularly true when seeking to collect data on transfected targets of interest, and on sensitive metabolic equilibria that occur on the order of minutes. The question remains: if we are …

Ocean Acidification Mitigation: Potential Expansion Of Sav Restoration Strategy In The Chesapeake Bay, Cree N. Taylor

Undergraduate Research Posters

Zostera marina is a species of marine macrophyte that has been largely prioritized in past submerged aquatic vegetation (SAV) restoration initiatives within the Chesapeake Bay because of its 1) previous abundance, 2) demonstrated carbon burial abilities, and 3) observed ability for meadows of Z. marina to ameliorate low pH conditions. Due to the temperature variability and poor water quality associated with anthropogenic disturbances in the Chesapeake Bay, Z. Marina beds have experienced several die-off events with limited capacity for regrowth. This systematic review explored the possible benefits of focusing future SAV recovery initiatives on ensuring a diverse variety of SAV …

Combining Esm Models With Experimentally Derived Structural Stability To Identify Functional Missense Mutations, Rucha Deo

Master's Projects

Missense mutations can impact protein function and structure, yet their effects on protein function are difficult to predict. In this study, I compared two deep learning models, ESM1v and ESM1b, by evaluating their mutation predictions against experimental structural stability data. ESM1v showed a stronger correlation with experimental structural stability scores compared to ESM1b. A sigmoid curve was fitted to explore this relationship further. Over 100,000 mutations were identified where experimental stability differed significantly from model predictions. Many mutations that remained structurally stable experimentally but were predicted as harmful by the ESM models were frequently found at known functional sites. Structural …