Biochemistry, Biophysics, and Structural Biology Commons^™

Machine-Learning Qsar-Based Novel Drug Identification To Inhibit Retinoblastoma Extracellular Vesicle Release And Metastatic Signaling, Kunhui Huang

Dissertations, Theses, and Capstone Projects

Extracellular vesicles (EVs) are lipid-enclosed particles that are generated by most types of cells and have been identified as an important mechanism for cell communication aside from cell direct contact. EVs contain a variety of functional macromolecules including proteins, lipids, RNA, which can be transferred from the host cells to target cells at a distance. The molecular pathways of EV biogenesis have been studied intensely in recent decades and the process involves several key genes and proteins. Cancer cell released EVs target distant tissues and upregulate signals that are attractive to cancer cell homing, playing a role in tumor progression …

Integrating In Vitro And In Silico Approaches To Gain Insight Into The Mechanism Of Amyloid Fibrillogenesis, Marvin M. Bilog

Dissertations, Theses, and Capstone Projects

Amyloid fibril formation, the hallmark of numerous amyloid-related diseases, has been the subject of a vast number of scientific studies due to its pathological implications. Since the fibrillization process exhibits a certain level of intricacy, its investigation requires a multidisciplinary approach that integrates both experimental and computational methods. In vitro techniques involve biophysical assays and imaging tools for characterizing the structural and kinetic aspects of amyloid fibril formation. In parallel, in silico techniques offer programs for predicting atomistic details and behaviors of amyloidogenic proteins and peptides at the nanoscale level. Serum amyloid A (SAA), human islet amyloid polypeptide (hIAPP), and …

Modeling Hydroxide In Classical Proton Hopping Simulations And Amyloid Beta Membrane Pores, Ankita Dutta

Dissertations, Theses, and Capstone Projects

H3O+ and OH- ions display anomalously large diffusion coefficients, a property that is often attributed to their ability to perform structural diffusion which allow these ions to move through aqueous solutions by sequential proton transfers, also known as ‘Grotthuss hopping’. A rearrangement of the local solvation structure is known to be the prerequisite for proton transfer events via these ions. Studying this phenomenon using classical molecular dynamics simulations that do not allow bond rearrangements poses significant obstacles. Here we use a Monte Carlo augmented classical Molecular Dynamics method called the MOBHY algorithm which allows instantaneous changes in protonation states in …

Mechanistic And Engineering Studies Of Lov Photoreceptors In Yeast, Matthew M. Cleere

Dissertations, Theses, and Capstone Projects

A variety of cellular biosensors have evolved which can translate electromagnetic radiation from the environment into biological functions. Light-Oxygen-Voltage (LOV) domains in particular, are a group of photoreceptors that respond to blue wavelengths of light and can become a cellular photoswitch by converting this stimulus through their attached effector domains. For instance, the Helix-Turn-Helix (HTH) DNA-binding activity of the bacterial transcription factor EL222 and the Regulator of G-protein Signaling (RGS) in the fungal membrane associating protein BcLOV4 are both induced by blue-light sensing LOV domains. While previous work has provided the field with a structural characterization of LOV proteins in …

Comparative Animal Mucomics, Antonio R. Cerullo

Dissertations, Theses, and Capstone Projects

Mucus is one of Nature’s most abundant and versatile biomaterials. These secretions are present in all animals, from the lowly garden snail to the great blue whale, and fulfill a multitude of functions, acting as antimicrobial barriers, moisturizers, adhesive glues, surface lubricants, and mineralizing agents. Despite their importance, very little is known about mucus compositions or properties. The largest challenge precluding the greater understanding of mucus function is its complexity; a single mucus contains complex mixtures of proteins, glycans, and ions that all have important roles in function. Therefore, understanding mucus function necessitates analysis that compares different mucus from one …

Protein-Protein Interactions In Cell Cycle Proteins: An In Silico Investigation Of Two Important Players, Andriele Eichner

Dissertations, Theses, and Capstone Projects

The examination of the cell cycle carries significant implications for the biology, health, and overall existence of all living things. These implications span from the development and growth of these organisms to the aging process and cancer, as well as the potential of stem cell therapies to repair diseases and injuries. Numerous proteins of the cell cycle are essential for cellular division and proliferation and are widely conserved over the course of evolution. In this work, we aimed to investigate the molecular processes of protein-protein interactions in cell cycle proteins, centering on two key players: Cdc6 in budding yeast and …

Rational Design Of Peptide-Based Materials Informed By Multiscale Molecular Dynamics Simulations, Dhwanit Rahul Dave

Dissertations, Theses, and Capstone Projects

The challenge of establishing a sustainable and circular economy for materials in medicine and technology necessitates bioinspired design. Nature's intricate machinery, forged through evolution, relies on a finite set of biomolecular building blocks with through-bond and through-space interactions. Repurposing these molecular building blocks requires a seamless integration of computational modeling, design, and experimental validation. The tools and concepts developed in this thesis pioneer new directions in peptide-materials design, grounded in fundamental principles of physical chemistry. We present a synergistic approach that integrates experimental designs and computational methods, specifically molecular dynamics simulations, to gain in-depth molecular insights crucial for advancing the …

Biomolecular Crystals As Functional Materials, Fahmeed Khan Sheehan

Dissertations, Theses, and Capstone Projects

The field of supramolecular chemistry has undergone significant evolution over the last few decades, progressing from fundamental studies of self-assembling systems to the rational design of functional materials with exceptional properties. Among these materials, short peptides have emerged as a chemically simple yet highly versatile class of biomimetic compounds. Initially, short peptides were used as model systems to understand larger protein interactions. As the field progressed, short peptides were found to have exceptional functionality, and are now explored as functional nanomaterials for diverse applications. In many cases, short peptide materials have displayed properties not found in biology, in some cases …

Characterization Of Pathological Tau Mutants, Charles J. Mcdonald

Dissertations, Theses, and Capstone Projects

Tau is a protein expressed exclusively in glia and neurons in the central nervous system and implicated in several neurogenerative diseases called “tauopathies”. Among all the tauopathies, one third is characterized by the presence of genetic mutations leading to the synthesis of tau proteins with single amino acid substitutions at specific locations and affecting protein function. While most of the initial studies have emphasize the functional role of tau as modulator of the axonal cytoskeleton, it has recently been well accepted that tau is also an intrinsically disordered protein that tends to form membraneless organelles called coacervates, due to a …

Characterization And Modulation Of The Emergent Material Properties Of Biomolecular Condensates, Alfredo Vidal Ceballos

Dissertations, Theses, and Capstone Projects

The discovery of membraneless organelles has revolutionized the field of cell biology and our understanding of cell compartmentalization. These organelles lack a distinct phospholipid bilayer and interact with the cytoplasm mediated by a liquid-liquid interface. The emergent properties and characterization of these organelles are essential for decoding the mechanisms underlying their function and dysfunction. In this thesis, we focus on two reconstituted in-vitro model systems of protein condensates and advance current methodology in order to address these fundamental questions. The first model system examined is the neuronal granule protein Fragile X Mental Retardation Protein (FMRP), an RNA-binding protein, that aids …

Magnetically-Driven Therapeutic Agents Delivery System Using Iron Oxide Nanocages And Enhancement Of Exosome Secretion, A Potential Biological Drug Delivery Carrier, Min A Kang

Dissertations, Theses, and Capstone Projects

Nano-scale particles have attracted research attention due to their differences in properties such as penetration, circulation, and toxicity compared to bulk materials. This thesis mainly focused on using 20 nm iron oxide nanoparticles as siRNA delivery carriers under the alternating magnetic field and the development of a method to amplify the secretion of 150 nm exosomes from the cells, which could potentially use as a biological drug carrier.

Chapter 2 discusses a magnetically driven nanoparticle therapeutic agent delivery system, which efficiently modified the gene expression post-transcriptionally. In this work, we examined whether the caged-shaped 20nm iron oxide nanoparticles (IO-nanocages) can …

Changes In The Epigenetic Landscape Of Oligodendrocyte Progenitor Cells With Time, David K. Dansu

Dissertations, Theses, and Capstone Projects

Most neonatal oligodendrocyte progenitors (nOPCs) give rise to myelinating oligodendrocytes during development, while a proportion are retained as proliferative undifferentiated cells in the adult brain (aOPCs). Previous studies have reported distinct properties for those two populations but the molecular mechanisms underlying these intrinsic differences are not well understood. Using RNA-sequencing and unbiased histone proteomics analysis, we identify transcripts and histone marks that are higher in aOPCs than nOPCs. The genome-wide ChIP-sequencing analysis of chromatin from aOPCs compared to nOPCs detects greater occupancy of the H4K8ac mark at loci corresponding to the higher transcript levels of oligodendrocyte-specific transcription factors and lipid …

Out-Of-Distribution Generalization Of Deep Learning To Illuminate Dark Protein Functional Space, Tian Cai

Dissertations, Theses, and Capstone Projects

Dark protein illumination is a fundamental challenge in drug discovery where majority human proteins are understudied, i.e. with only known protein sequence but no known small molecule binder. It's a major road block to enable drug discovery paradigm shift from single-targeted which looks to identify a single target and design drug to regulate the single target to multi-targeted in a Systems Pharmacology perspective. Diseases such as Alzheimer's and Opioid-Use-Disorder plaguing millions of patients call for effective multi-targeted approach involving dark proteins. Using limited protein data to predict dark protein property requires deep learning systems with OOD generalization capacity. Out-of-Distribution (OOD) …

Construction And Performance Optimization Of Bioconjugated Nanosensors For Early Detection Of Breast Cancer And Pro-Inflammatory Diseases, Pooja Gaikwad

Dissertations, Theses, and Capstone Projects

In recent years, nanosensors have emerged as a tool with strong potential in medical diagnostics. Single-walled carbon nanotube (SWCNT) based optical nanosensors have notably garnered interest due to the unique characteristics of their near-infrared fluorescence emission, including tissue transparency, photostability, and various chiralities with discrete absorption and fluorescence emission bands. Additionally, the optoelectronic properties of SWCNT are sensitive to the surrounding environment, which makes them suitable for in vitro and in vivo biosensing. Single-stranded (ss) DNA-wrapped SWCNTs have been reported as optical nanosensors for cancers and metabolic diseases. Breast cancer and cardiovascular diseases are the most common causes of death …

Characterization Of The Conformational Binding Of N-Methyl Mesoporphyrin Ix With Dna Model Telomeric G-Quadruplex Forming Sequences, Jessica Desamero

Dissertations, Theses, and Capstone Projects

DNA G-quadruplexes are alternative secondary structures formed from guanine rich DNA sequences. G-quadruplexes are found most abundantly at the ends of chromosomes called telomeres, where they can ultimately prevent further tumor growth and progression. Thus, quadruplex interactive agents, or ligands that can bind to and stabilize DNA G-quadruplex structures, are of high interest for their potential chemotherapeutic abilities. One quadruplex interactive agent is the porphyrin N-methyl mesoporphyrin IX (NMM), which has high binding selectivity for quadruplex structures. While the NMM-quadruplex complex in crystallized form has been greatly studied, this complex in solution form is not as well studied. Through circular …

Optimization And Application Of Graph Neural Networks, Shuo Zhang

Dissertations, Theses, and Capstone Projects

Graph Neural Networks (GNNs) are widely recognized for their potential in learning from graph-structured data and solving complex problems. However, optimal performance and applicability of GNNs have been an open-ended challenge. This dissertation presents a series of substantial advances addressing this problem. First, we investigate attention-based GNNs, revealing a critical shortcoming: their ignorance of cardinality information that impacts their discriminative power. To rectify this, we propose Cardinality Preserved Attention (CPA) models that can be applied to any attention-based GNNs, which exhibit a marked improvement in performance. Next, we introduce the Directional Node Pair (DNP) descriptor and the Robust Molecular Graph …

Structural Basis Of Signal Transduction Within Environmental Sensing Pas Regulated Ser/Thr Kinases, Roksana Azad

Dissertations, Theses, and Capstone Projects

To sense environmental cues, nature has evolved molecular switches that are widely used across life. This process often relies on environmentally controlled PPIs (Protein-Protein Interactions) within a sensory domain that senses various stimuli and alters the functional activities of downstream effectors. This study focused on the superfamily of PAS (Per-ARNT-Sim) environmental sensory domains and their roles in regulating two Ser/Thr Kinases (STKs). PAS domains achieve their regulatory control by internally binding small molecule ligands/cofactors (e.g., O₂ binding to heme …

Singlet Oxygen-Mediated Conformational Flexibility, Antioxidant, And Isomerization Studies In Chemistry And Biochemistry, Oliver Turque

Dissertations, Theses, and Capstone Projects

Three chapters are included in this dissertation, each of which describes non-oxidative reactions, with peroxy intermediates formed between singlet oxygen (¹O₂) and substrate. (1) Novel discoveries related to the intermediate formed by ¹O₂ and dimethyl disulfane are explored. (2) A new mechanism is proposed, wherein the dihedral angle CS–SC (θ) determines the pro- or antioxidant activity of an organic disulfide. (3) A review of ¹O₂'s ability to facilitate the geometric isomerization of alkenes and polyenes is presented in Chapter 3.

Chapter 1 investigates the role of singlet oxygen potentially …

Leveraging Local Perturbations To Map Allosteric Networks Of Phosphatases, Tamar (Skaist) Mehlman

Dissertations, Theses, and Capstone Projects

Allostery is central to regulation of protein function, but our mechanistic understanding remains incomplete. A deeper understanding of how redistributions of conformational states drive allostery in proteins could allow us to better grasp natural regulatory principles in cells and open new doors to therapeutic development. Conformationally dynamic human Protein Tyrosine Phosphatases (PTPs) exemplify the challenges and opportunities associated with allostery. The archetypal PTP, PTP1B, has been highly validated as a therapeutic target but no allosteric inhibitors have been approved for clinical use. This is largely because our understanding of the mechanisms underlying allostery in PTP1B remains limited, despite the discovery …

The Development Of Novel Radioimmunoconjugates For The Pet Imaging And Radioimmunotherapy Of Cancer, Samantha M. Sarrett

Dissertations, Theses, and Capstone Projects

Antibodies have long played a vital role in nuclear medicine for both the diagnosis and therapy of various malignancies. The role and development of antibodies in nuclear medicine can be broadly separated into three different categories: 1) bioconjugation strategies, 2) immunoPET imaging, and 3) radioimmunotherapy. This dissertation will attempt to comprehensively cover each of these categories through a series of studies, protocols, and reviews. For the bioconjugation strategies, we will describe the development of a novel site-selective bioconjugation strategy using an innovative lysine-targeting reagent, PFP-bisN₃, to prepare [⁸⁹Zr]Zr-^SSKDFO-pertuzumab for visualizing HER2+ breast cancer. Further, …

Multi-Target Ligand-Guided Selection (Ligs) Against B-Cell Specific Antigens Expressed In A Single Lymphoma Cell Population, Nicole B. Williams

Dissertations, Theses, and Capstone Projects

Nucleic acid ligands called aptamers are single-stranded DNA or RNA molecules which fold into functional three-dimensional structures to facilitate their target binding with high affinity and specificity. The method used to generate aptamers is an in vitro process called Systematic Evolution of Ligands by Exponential enrichment (SELEX). A variant of SELEX, cell-SELEX has been used to select aptamers against cell-surface proteins in their native state. We recently introduced a novel method called Ligand-Guided Selection (LIGS) to identify aptamers against cell-surface markers. Herein, we expanded LIGS method into a multiplexing platform to partition multiple aptamers against B-cell-specific antigens, CD19 and CD20, …

Metabolic Reprogramming In Kras-Driven Cancer Cells, Ahmet Hatipoglu

Dissertations, Theses, and Capstone Projects

Cancer cells require nutrient uptake for anabolic reactions needed for cellular growth and proliferation. The mammalian target of rapamycin (mTOR) is a key regulator of cellular growth that links nutrient availability and growth factor signals. mTOR mediated signaling pathways are often dysregulated in a wide range of cancers. We previously reported that KRas-driven cancer cells sense exogenous lipids via de novo production of phosphatidic acid, which ultimately activates both mTOR complexes – mTORC1 and mTORC2. Activated mTORC2 phosphorylates the survival kinase Akt at Ser 473 which is required for full Akt activation. A direct substrate of Akt and a major …

Targeting Hif/Coregulator Complexes In Cancer: Characterizing Fragile Fold And Inhibitor Binding Sites Of Arnt, Xingjian Xu

Dissertations, Theses, and Capstone Projects

Hypoxia-inducible factors (HIFs) are transcription factors that play crucial roles in regulating adaptive cellular responses to low oxygen concentrations (hypoxia). Structurally, HIFs are heterodimers composed of one of three α-subunits (HIF-1α, -2α, and -3α) and a β subunit (HIF-β, also known as ARNT), with the heterodimerization mediated by the tandem PAS domains (PAS-A and PAS-B) found within both proteins. Dysregulation of the HIF pathway has been implicated in various types of cancers, contributing to cancer cell survival, tumor growth and progression, and resistance to therapies, resulting in poor treatment outcomes. As such, HIF-specific inhibitors have been extensively investigated as novel …

Engineered Plga Nanofibers For Drug Delivery, Andrew Mancuso

Dissertations, Theses, and Capstone Projects

Poly-lactic-co-glycolic acid (PLGA) polymers are rapidly gaining momentum as a platform for next-generation drug delivery systems due to their ease and low cost of synthesis, favorable biocompatibility and biodegradability, and lack of toxicity. In particular, the application of drug-loaded PLGA nanofibers directly to a target tissue may represent a promising alternative to traditional routes of drug administration (e.g., oral, injectable) as they offer the potential to greatly improve bioavailability, increase efficacy, and reduce off-target toxicity. Furthermore, the use of such a system may potentially allow for greater flexibility in clinical drug development, by enabling the use of compounds which have …

Genetic Determinants Involved In Acquisition Of Iron In The Opportunistic Pathogen Mycobacterium Abscessus, Manal F. Farhat

Dissertations, Theses, and Capstone Projects

The opportunistic pathogen Mycobacterium abscessus subsp. abscessus (Mab) has become an emerging public health threat due to the increasing number of Mab-associated chronic pulmonary disease cases. Infection cure rates are only 50% due to the complex resistance of Mab to most antimicrobial drugs and chemotherapy.

Deeper knowledge of Mab biology is needed to illuminate potential candidates for development of improved therapeutics against Mab infections. The ESX-3 type VII protein secretion system of Mab plays an important role in host inflammatory and pathological responses during infection.

In this study, we demonstrate a functional link between the ESX-3 secretion …

Leveraging Bio-Inspired Molecules For Cancer Theranostics, Douglas S. Macpherson

Dissertations, Theses, and Capstone Projects

A variety of molecules can be radiolabeled and delivered to a cancer site for the purposes of diagnostics and therapy. Among the most promising of tumor targeting molecules are peptides and antibodies. These bio-inspired molecules can be designed and synthesized to target and respond to cancer cells based on the properties of those cells. Matrix metalloproteinase (MMP) enzymes are over-expressed by some metastatic cancers, in which they are responsible for the degradation and remodeling of the extracellular matrix. In recent years, MMPs have emerged as promising targets for enzyme-responsive diagnostic probes because oligopeptides can be designed to be selectively hydrolyzed …

Role Of Nuclear Lamins In Oligodendrocyte Lineage Cells, Camila Yattah

Dissertations, Theses, and Capstone Projects

Differentiation of oligodendrocytes from progenitor cells is a highly regulated process characterized by a series of molecular changes, resulting in nuclear and morphological features unique to the mature oligodendrocyte state. Heterochromatin formation starting at the nuclear periphery, as well as increased nuclear rigidity are characteristically observed. The nuclear periphery is characterized by the presence of the nuclear lamina and it has been implicated in higher-order genome organization in cells. Lamins are the protein components of the nuclear lamina, and their expression is dependent upon the cell differentiation stage of the cells. While Lamin B1 (LMNB1) expression is high in progenitors …

Prenatal Choline Supplementation During Maternal Obesity Alters Offspring Response To Western Diets, Hunter W. Korsmo

Dissertations, Theses, and Capstone Projects

Maternal obesity has led to an increase in adverse offspring developmental outcomes and a greater risk for long-term metabolic diseases. Choline, a semi-essential nutrient, can be incorporated into phosphatidylcholine (PC) as well as sphingomyelin (SM) and donate its labile methyl group for the remethylation of homocysteine after choline is oxidized to betaine. Prenatal choline insufficiency has been related to maternal obesity and metabolic diseases, such as metabolic associated fatty liver disease (MAFLD). Choline may interact with maternal obesity to influence the programming offspring.

Chapter 1 presents an introduction of choline and the various clinical outcomes associated with choline supplementation during …

Isolation And Characterization Of Fluorescent Proteins And Small Molecules From Marine Vertebrates, Sara Rose Krivoshik

Dissertations, Theses, and Capstone Projects

Fluorescence is a phenomenon in which a wavelength of light excites a fluorophore and then emits light at a higher, longer wavelength. This occurs throughout the biological world, in both the terrestrial and marine realms. Encompassing a diverse set of mechanisms from small molecules to large protein complexes; fluorescence has been used as a biological tool with a wide range of applications to study molecular and cellular biology for decades. This dissertation looks to identify and characterize novel fluorescent proteins and small molecules to allow for more efficient translation in developing new biotechnologies. Using a combination of RNA-Seq, Mass-Spec, protein …

Determining The Roles Of The Oligomerization And C-Terminal Domains In Mutant P53 Gain-Of-Function Activities, George K. Annor

Dissertations, Theses, and Capstone Projects

The tumor suppressor p53 (TP53) gene is often mutated in cancer, with missense mutations found in the central DNA binding domain, and less often in the oligomerization domain (OD) and C-terminal domain (CTD). The OD and CTD have been found to be critical for the tumor suppressor functionality of wild-type p53 (wtp53). Specific missense mutations in the DNA binding domain have been found to confer new gain-of-function (GOF) activities. Mutations that destabilize tetramer formation, or deletion of key lysine residues within the CTD, downregulate the ability of wtp53 to transactivate (increase the rate of transcription of) its target …