Amino Acids, Peptides, and Proteins Commons^™

Towards The Synthesis Of Dragonamide E And Analogs Thereof, Dante Glover

Chemistry Theses

Leishmaniasis is a disease caused by a parasite spread through the female sand fly. It is categorized as a Neglected Tropical Disease and can cause very severe symptoms, even death, if left untreated. Symptoms include skin lesions that can cause permanent scarring, and mucosal membrane infections that can cause facial deformities. More aggressive forms of leishmaniasis can lead to infections of internal organs like the liver and/or spleen and can lead to death. Drug resistance of these parasites has rendered treatment limited and the side effects of which can be harmful as well.

Scientists looking towards new treatments for tropical …

Computational Insights Into Nucleosome Dynamics In Epigenetics Using Molecular Dynamics Simulations, Rutika Patel

Dissertations, Theses, and Capstone Projects

Nucleosome core particles (NCP) are the building blocks that form a highly organized and compact chromatin structure. Nucleosomes package DNA in the nucleus of eukaryotic cells. The NCP consists of about 147 base pairs of DNA wrapped around the histone octamer, with 1.65 superhelical turns in a left-handed manner. The histone octamer is composed of two copies of H3, H4, H2A, and H2B. Together with histone H1 and linker DNA, they further assemble into a higher-order chromatin structure. The nucleosome complex is stabilized by electrostatic interactions between positively charged histone residues and the negatively charged DNA backbone. To effectively access …

Abnormal Trafficking And Processing Of Multiple Matrix Metalloproteinases Drive Cartilage Defects In Congenital Disorders Of Glycosylation, Chia-Lun Wu

All Dissertations

Congenital Disorders of Glycosylation (CDG) are rare metabolic diseases caused by defects in glycosylation. Despite identification of over 200 CDG types, the mechanisms linking glycosylation defects to diverse clinical phenotypes remain unclear. This dissertation uses zebrafish models of PMM2-CDG and STT3-CDG to redefine CDG pathogenesis, shifting from a simple glycan deficiency model to one involving disrupted cellular spatial organization.

We identify a protease-dependent pathway underlying craniofacial cartilage defects. Specifically, defective proteolytic processing of N-cadherin, a key adhesion molecule in chondrogenesis, is a central driver of pathology. We further uncover an unconventional trafficking mechanism in which ER stress and altered secretory …

Understanding The Role Of Toxs As A Bile Sensing Component Of The Toxrs Virulence Regulatory System In Vibrio Spp., Minje Kim

Dartmouth College Ph.D Dissertations

Pathogenic Vibrio bacteria, such as V. cholerae and V. parahaemolyticus, colonize in the human small intestine to cause severe gastrointestinal disease. During the infection, these bacteria encounter bile salts, antimicrobial cholesterol metabolites secreted into the intestine. Pathogenic Vibrio species have evolved to utilize bile salts as signals to regulate virulence. The signaling depends in part on ToxRS, a conserved co-component transmembrane transcription regulator. ToxRS consists of the transcription factor ToxR and its membrane-tethered binding partner ToxS. ToxS is required for ToxR stability and full transcriptional activity. Although bile salts are known to influence ToxRS-dependent virulence gene expression, the molecular …

Increased Backbone Rigidity Of Artificial Transcription Factors, Jasmine Glover, Emma Otey, Joanna K. Kwao, Nicholas Truex

Senior Theses

Programming DNA-binding proteins is an effective strategy for developing therapeutics that regulate gene expression. These proteins can directly bind to DNA to activate or repress transcription of specific genes. Zinc finger proteins are a class of DNA-binding proteins commonly found in eukaryotic organisms. Their DNA-binding function is derived from unique amino acid sequences within each domain that recognizes specific nucleotides, allowing each finger to selectively recognize three DNA base pairs. Adjoining of multiple domains in tandem allows recognition of a specific DNA sequence. Artificial transcription factors can be made of multiple zinc finger domains arranged in tandem and engineered to …

Engineering Enac Constructs To Examine Pip2 And Ubiquitin Competition On Enac Regulation And Stability, Lacie Johnson

Chemistry & Biochemistry Undergraduate Honors Theses

The epithelial sodium channel (ENaC) plays a critical role in sodium homeostasis, fluid balance, and blood pressure regulation. ENaC activity is tightly controlled by post-translational mechanisms, including ubiquitination-mediated degradation and phosphatidylinositol 4,5-bisphosphate (PIP2) dependent channel activation. PIP2 is a phospholipid necessary to facilitate the maximal channel opening. Previous studies suggest that intracellular PIP2 binding sites are located in proximity to ubiquitination sites on ENaC subunits, raising the possibility of PIP2 binding to influence channel stability and function. This thesis aimed to engineer and validate molecular tools capable of examining the interplay between PIP2 binding and ubiquitination in ENaC regulation. A …

Sexually Dimorphic Effects Of Gpnmb Modulation On Vertebral Bone Mass Regulation And Intravertebral Disc Health, Hakem Altawil, Fayez Safadi

Williams Honors College, Honors Research Projects

Osteoporosis and vertebral degeneration are major contributors to musculoskeletal morbidity, yet the molecular mechanisms regulating vertebral bone and intervertebral disc (IVD) homeostasis remain incompletely understood. GPNMB (osteoactivin) has been identified as a regulator of bone remodeling, though its role in spine health is unclear. This study evaluated the effects of GPNMB deficiency on lumbar vertebral bone microarchitecture and IVD integrity in a sex-dependent context.

Six-month-old male and female wild-type (WT) and GPNMB knockout (KO) mice were analyzed using micro–computed tomography (µCT) of lumbar vertebrae (L4–L6) and histological assessment of the L5–L6 IVD. KO males exhibited increased bone volume fraction, bone …

Studies Towards Chemical Synthesis Of Homogeneous Prion Glycoprotein, Baotong Tian

Electronic Theses & Dissertations (2024 - present)

Prion diseases are fatal neurodegenerative disorders initiated by conformational misfolding of the prion protein (PrP), which generates pathogenic conformers that propagate via templated conversion and accumulate as aggregates. Glycosylation can modulate the PrP folding energy landscape, thereby biasing folding trajectories and the distribution of resulting conformational states. Bank vole PrP contains two N-linked glycosylation sites, and disentangling the contributions of site occupancy versus glycan structure requires homogeneous, site-defined glycoforms. In contrast, biosynthetic expression typically produces heterogeneous glycoform ensembles due to multistep Golgi processing, precluding independent control of glycan identity at each site. Here we report a chemical synthesis strategy of …

Optimizing Endothelial Cell Specific Polymersome-Based Atheroprotective Therapies, Ally C. Brawner

All Theses

Atherosclerotic cardiovascular disease is the number one cause of death in the United States and the world. Every year, billions of dollars are spent in the US alone for direct treatments of this disease, especially on prescription medicines like statins. However, these medications have been unable to curtail global mortality rates, partially because they do not target the entirety of atherosclerotic pathophysiology. A key area of this pathophysiology is that atheroprone arteries typically include pro-inflammatory endothelial cells that exhibit decreased levels of apoAI-mediated cholesterol efflux and an increased release of adhesion molecules, such as VCAM-1. The objective of my project …

Biofluid Biomarkers Aid In Diagnosing And Developing Improved Treatments For People With Alzheimer's Disease, Jonatan A. Lopez

University Honors Theses

Dementia is a disease in which daily life is disrupted by a loss of cognitive function. Late-onset Alzheimer's disease (AD) is the most common dementia that largely begins to affect individuals in their mid 60s or older. AD was selected as the focus of this paper because it is the most common form of dementia, accounting for 50-70% of dementia cases. A typical diagnostic approach used by physicians starts with a simple clinical test, the Mini-Mental State Examination (MMSE), when cognitive decline is suspected in a patient. Then if there is enough evidence to suggest AD, a physician would order …

Impact Of Cysteine And Tyrosine Dipeptides On Cho Cell Performance In A Perfusion Mimic, Corrin L. Pruitt

All Theses

Perfusion cell cultures typically achieve higher cell densities and generate higher volumetric productivities than fed-batch cultures due to continuous nutrient supply and spent media removal. Despite these advantages, perfusion cell cultures remain underutilized for licensed product manufacturing, primarily due to the lack of small-scale perfusion models for high-throughput process development and the complexities involved in media formulation capable of supporting high cell densities during long-term continuous operation. To avoid nutrient limitation at high cell densities, current perfusion processes rely on using higher perfusion rates, which results in significant media wastage and downstream product dilution. Therefore, there has been an effort …

Cbl Regulation Of C-Met Signaling In Corneal Epithelial Cells., Kate Elise Tarvestad Laise

Electronic Theses and Dissertations

The cornea is the most anterior portion of the eye and permits light passage through to retina, allowing formation of a clear image as long as it remains healthy. If the cornea sustains damage, it creates and entrance for foreign body invasion, infection, and ultimately blindness in the immunocompromised eye. Healing the corneal tissue is critical for vision restoration and pain alleviation, as it is the most densely innervated tissue in the body. Growth factors and their cognate receptors are currently under investigation as tools to restore proper corneal physiology. We hypothesize that manipulating the hepatocyte growth factor (HGF) /c-Met …

A Mutational Analysis Of Thatisin: How Single Point Mutations Impact The Biosynthetic Process Of A Group 16 Graspetide, John F. Boynton Jr

Chemistry and Chemical Biology ETDs

Abstract:

Graspetides are a family of Ribosomally synthesized and Post-translationally modified Peptide (RiPP) natural products named for their ATP Grasp Macrocyclases. We identified several Graspetide Biosynthetic Gene Clusters containing common double glycine cleavage motifs and attempted characterization of the mature Graspetides. One of the resulting peptides, Thatisin, has a topology with two interlocking macrolactones installed by a single ATP Grasp Ligase named ThtC. Here we use single and double point mutations to observe the impact or variation on the installation of these macrocycles. Alanine scan mutagenesis is used to assess leader peptide residues in the precursor peptide ThtA to determine …

Investigating The Cytotoxic Effects Of Amino Acid-Based Ionic Liquids And Peg-Pla Nanoparticles On Mcf10a Human Breast Epithelial Cells For Drug Delivery Applications, Ella C. Mertins

Honors Theses

This study investigates the cytotoxic effects of polyethylene glycol-polylactic acid (PEG-PLA) nanoparticles (NPs) both bare and coated with choline-based ionic liquids (ILs) on MCF10A human breast epithelial cells. The goal was to evaluate how IL-modified NPs influence cell viability at varying concentrations and to assess their potential as drug delivery systems. Three choline-based ILs, Choline-L-Asparagine 1:1, Choline-DL-Isoleucinate 1:1, and Choline-L-Leucinate 1:1, were used as surface coatings for PEG-PLA NPs. Additionally, the ILs were tested independently to establish a baseline for their cytotoxicity. Using a luminescent ATP-based viability assay following the treatment of MCF10A cells, the ILs were found to be …

Computationally Assessing The Specificity Of Receptor Tyrosine Kinase Inhibitors, Htoo Say

Theses/Capstones/Creative Projects

Receptor tyrosine kinases (RTKs) are vital to cell signaling processes such as growth, survival, and differentiation. Dysregulation through mutation or overexpression often contributes to cancer, making RTKs key therapeutic targets for tyrosine kinase inhibitors (TKIs). However, the low specificity of many TKIs leads to off-target effects. This project uses molecular docking to evaluate the binding affinities and selectivity of FDA-approved TKIs across 18 RTK subtypes. The dockings conducted revealed significant variability in binding affinities, with Sorafenib exhibiting strong specificity for EphB2 (-7.6 kcal/mol) and poor compatibility with EphA7 and ErbB4 (-3.0 kcal/mol). These findings underscore the role of specific molecular …

Studies To Understand The Stability And Liabilities Of Legumain-Cleavable Antibody-Drug Conjugates, Michele Yi

Undergraduate Honors Theses

Antibody-drug conjugates (ADCs) offer targeted drug delivery of potent cytotoxic payloads, minimizing systemic toxicity. However, the stability of the linker is integral to ensure that there is minimal off-target payload release and little systemic toxicity. This study analyzes the physical and biological stability of our new legumain-cleavable vs traditional cathepsin-cleavable antibody-drug conjugates (ADCs), with a focus on hydrophobicity, thermal stability, aggregation, and biological payload release. Our findings indicate that decreased hydrophobicity of the legumain-cleavable ADCs compared to cathepsin-cleavable ADCs is correlated with decreased aggregation (predicting lower uptake by liver macrophages and therefore slower clearance and less systemic toxicity) and lower …

Hdac5 Enzymatic Activity Regulates Scn4b Expression To Control Relapse-Like Cocaine Seeking, Daniel J. Wood

MUSC Theses and Dissertations

Substance Use Disorder (SUD) is a relapsing disorder characterized by repeated seeking and use of psychoactive substances despite negative consequences to the individual. Epigenetic changes within the medium spiny neurons (MSNs) of the nucleus accumbens (NAc) are thought to underly the lasting propensity to relapse in SUD. The epigenetic enzyme histone deacetylase 5 (HDAC5) in NAc MSNs limits the formation of reward-cue associations in rodent models of drug seeking, but not sucrose seeking, leading to decreased relapse-like behavior. However, whether HDAC5 reduces drug seeking behavior through its own deacetylase activity or through the recruitment of co-repressors is unknown. Furthermore, these …

Ribosome Hibernation In Mycobacterium Abscessus And Its Effect On Antibiotic Resistance, Ryan Treen

Electronic Theses & Dissertations (2024 - present)

Non-tuberculosis mycobacteria (NTM) represent a diverse repertoire of species, most of which are ubiquitous in the environment. Some NTM species, such as Mycobacterium abscessus, can cause life-threatening infections in people with underlying medical conditions. The clinical incidence of such infections is on the rise, posing an emerging threat to public health. M. abscessus is characterized by intrinsic and acquired antibiotic resistance, complicating treatment strategies. Most chemotherapeutic approaches for M. abscessus infection target the bacterial ribosome, necessitating a better understanding of the physiological processes which confer this resistance. Multiple mycobacterial species respond to zinc-limiting conditions by inducing remodeling and hibernation …

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 …

Multimodal Imaging Of Protein-Based Biomaterials For Delivering Chemo-Agent Cargo For Glioblastoma Treatment In A Murine Model, Orin Mishkit

Dissertations and Theses

Protein-based self-assembling biomaterials, known as Thermo-Responsive Assembled Proteins (TRAP), present meaningful potential as drug delivery carriers. These materials enable the controlled, slow release of poorly soluble chemotherapeutic agents, such as doxorubicin (Dox), while potentially reducing systemic off-target effects. In collaboration with multiple NYU labs, this study evaluated the efficacy of two TRAP variants—TRAP and F-TRAP—as drug delivery carriers in a xenograft mouse model of glioblastoma multiforme (GBM).

The primary objective was to compare the effectiveness of TRAP-loaded Dox (TRAP-DOX) to free Dox in achieving tumor extravasation and accumulation, facilitating sustained drug release. We hypothesized that the leaky vasculature of GBM …

Asymmetric Synthesis Of The Hiv Protease Inhibitor Tmc-126 And An Anti-Malarial Agent Via A Titanium Tetrachloride Mediated Asymmetric Glycolate Aldol Addition Reaction. Redefining The Curtius Rearrangement Reaction Via Dehomologation Of Carboxylic Acids Bearing Alpha-Leaving Groups, Kweku Amaning Affram

Theses and Dissertations

Acquired Immune Deficiency Syndrome (AIDS) and malaria are two devastating infectious diseases caused by HIV and Plasmodium parasites. AIDS is caused by HIV-1 and HIV-2, transmitted through sexual contact, blood transfusions, needle sharing, and perinatal routes. Malaria, caused by plasmodium parasites through mosquito bites. Today, millions of people around the world have been infected with HIV and malaria and much research has been done to treat it. However, despite advancements in therapeutic options, these diseases remain a significant global health threat, particularly in developing countries due to the emergence of drug-resistant strains for both HIV and malaria complicating eradication efforts. …

Alpha-Synuclein Interaction With Gedunin, Tony Matundura Nyabayo

Graduate Theses/Dissertations

Parkinson’s disease (PD) and other Proteinopathies develop when α-synuclein misfolds and aggregates into toxic amyloids. While existing treatments for PD are primarily focused on managing its symptoms, a viable solution for slowing down the progress of Parkinson’s disease involves targeting the toxic α-synuclein amyloids. Gedunin, a natural inhibitor of heat shock protein 90, has been extensively used to treat malaria. Also, recent research investigations have shed light on its potential beyond malaria therapy, indicating that Gedunin may offer a possible solution for treating a variety of neurodegenerative diseases. Using plate-based assays, we examined how Gedunin influences α-synuclein fibrillation and its …

Structural Optimization And Stability Enhancement Of Uba(2) And Ntl9 Using The Computational Tool: Emcast, Bahar Ghazi Esfahani

Graduate Student Theses, Dissertations, & Professional Papers

This study enhances protein stability prediction by refining EmCAST (Empirical C-Alpha Stability Tool), a computational tool used to identify stabilizing mutations in protein domains. We applied EmCAST to two model proteins: the α-helical ubiquitin-associated domain 2 (UBA(2)) and the α/β N-terminal domain of ribosomal protein L9 (NTL9). Protein stability is critical for proper function, and mutations can lead to misfolding and disease. To validate EmCAST’s predictions, guanidine hydrochloride-induced denaturation was monitored using circular dichroism (CD) spectroscopy for both wild-type and mutant variants. Results guided refinements to EmCAST’s algorithm, incorporating new experimental datasets to improve accuracy. Additionally, we examined the assumption …

Redox Control In A Fused Electron Transfer Flavoprotein From A Thermophilic Archaeon And Expanded Significance Of A Hydrogen Bond From A Conserved Histidine Residue That Contributes To Flavin Redox Tuning And Activation For Covalent Modification, Debarati Das

Theses and Dissertations--Chemistry

In absence of O₂ as terminal electron acceptors in anaerobic bacteria and archaea, carbohydrate metabolism is 15 times less efficient compared to aerobic energy metabolism resulting in energy deficit conditions. Despite their meager resources these anaerobes were able to generate H₂ and a chemiosmotic potential able to drive energy demanding reactions such as CO₂ or N₂ fixation. These observations raised concerns as production of high energy reductants (H₂) from mediocre fuels (NADH) defied the laws of thermodynamics.

In 2008, a known mechanism “electron bifurcation” but with flavins as redox mediators instead of quinones was …

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 …

Assembly Of Ppsu-Oligomers, Mariam Nesterov

Student Theses and Dissertations

The development of nanostructures for delivering multiple proteins to targeted antibodies has become a promising avenue in biotechnology, driven by advancements in synthetic polymers like poly(propylene sulfone), PPSU. However, the PPSU polymer faces a major limitation - its high insolubility. To address this challenge, this study investigates whether PPSU oligomers can enhance both the solubility and stability of lysozyme, a model protein that is cost-effective and widely accessible. Using dimer, trimer, tetramer, and hexamer configurations, we analyzed the interactions between PPSU oligomer and lysozyme under varying conditions. Our results show that the dimer and trimer are water soluble (no aggregate …

Design, Synthesis, And Nmr-Guided Characterization Of A Targeted Covalent Inhibitor-Like Molecule Against Ivyp1 From P. Aeruginosa, Samuel Taylor Moore

Master's Theses

Multi-drug resistance poses a serious threat to future generations and historical antibiotic pipelines; consequently, the medical and economic burdens associated with treating multidrug-resistant bacteria are substantiated. In this context, P. aeruginosa (PA) emerges as one of the most significant healthcare challenges, being a leading cause of resistance-associated mortality worldwide. Despite modern efforts to combat these poor outcomes, drug-resistant cases continue to rise, and the need for novel antibiotic treatment is apparent. To this end, we investigated relevant resistance mechanisms and past antibiotic targets within PA, and in doing so, we identified relationships between peptidoglycan biology and a periplasmic protein, Inhibitor …

The Effects Of Cannabinoids On Migration-Related Protein Expression In Ewing’S Sarcoma, Allison Lashall

Theses

Ewing’s sarcoma is an aggressive pediatric bone cancer that has low five-year survival rates, primarily due to metastatic disease and resistance of recurring tumors to traditional treatment options; therefore, novel treatment options are needed. The compound cannabidiol (CBD) has been shown to reduce cell viability, migration, and invasion in several tumor types, though the cellular mechanism of action is not well understood. Our lab has demonstrated the ability of CBD to reduce viability, migration, and invasion of Ewing’s sarcoma cells in vitro and is investigating differential protein and cytokine expression of known mediators of migration, such as intercellular adhesion molecule …

Incorporating Solvation Thermodynamic Mapping In Computer-Aided Drug Design, Yeonji Ji

Dissertations, Theses, and Capstone Projects

Advancements in computational techniques have revolutionized structure-based drug design, substantially improving the efficiency and effectiveness of the drug discovery process by reducing time, costs, and labor requirements. These advancements include various methods, such as investigating small molecule ligands binding to proteins, exploring alternative protein conformations, and solvation mapping on the protein surfaces. Among these methods, understanding the correlation between protein-ligand binding and the role of solvation is important.

A fundamental concept in protein-ligand binding is shape and electrostatic complementarity, which is complicated by the inherent flexibility of proteins. In the absence of small molecule ligands, proteins are complementary to surface …

Exploiting The Heavy Chain Glycans For The Improvement Of Radioimmunoconjugates, Cindy Rodriguez

Dissertations, Theses, and Capstone Projects

Radiolabeled antibodies have become indispensable tools in nuclear medicine. However, the natural roles of antibodies within the immune system mean that they have several intrinsic limitations as a platform for radiopharmaceuticals. A handful of recent preclinical studies suggest that binding by FcR and particularly FcyRI can affect the pharmacokinetic profiles of 89Zr-labeled radioimmunoconjugates. Fc receptors (FcR) are responsible for many of the interactions between immunoglobulins (IgG) and immune cells. In biomedicine, this interplay is critical to the activity of several types of immunotherapeutics; however, relatively little is known about how FcRs affect the in vivo performance of radiolabeled antibodies. Antibodies …