Biochemistry, Biophysics, and Structural Biology Commons^™

A Structural Role For Tryptophan In Proteins, And The Ubiquitous Trp CΔ1—H&Centerdot;&Centerdot;&Centerdot;O=C (Backbone) Hydrogen Bond, Michal Szczygiel, Urszula Derewenda, Steve Scheiner, Wladek Minor, Zygmunt S. Derewenda

Chemistry and Biochemistry Faculty Publications

Tryptophan is the most prominent amino acid found in proteins, with multiple functional roles. Its side chain is made up of the hydrophobic indole moiety, with two groups that act as donors in hydrogen bonds: the N^ε—H group, which is a potent donor in canonical hydrogen bonds, and a polarized C^δ1—H group, which is capable of forming weaker, noncanonical bonds. Due to adjacent electron-withdrawing moieties, C—H···O hydrogen bonds are ubiquitous in macromolecules, albeit contingent on the polarization of the donor C—H group. Consequently, C^α groups (adjacent to the carbonyl and amino groups of flanking peptide …

Roles Of Mitochondrial Chchd2 And Gpcr-Associated Β-Arrestin2 In The Pathogenesis Of Lewy Body Disorders, Teresa R. Kee

USF Tampa Graduate Theses and Dissertations

Coiled-coil-helix-coiled-coil-helix domain containing 2 (CHCHD2) is a mitochondrial protein that plays important roles in cristae structure, oxidative phosphorylation, and apoptosis. Multiple mutations in CHCHD2 have been associated with Lewy body disorders (LBDs), such as Parkinson’s disease (PD) and dementia with Lewy bodies (DLB), with the CHCHD2T61I mutation being the most widely studied. We generated the first transgenic mouse models expressing human CHCHD2WT and the PD-linked CHCHD2T61I mutation driven by the mPrP promoter. CHCHD2T61I Tg, but not CHCHD2WT Tg mice exhibit perinuclear mitochondrial aggregates, neuroinflammation, and have impaired long-term synaptic plasticity associated with synaptic dysfunction. Dopaminergic neurodegeneration, a hallmark of PD, …

Functional Studies Of Dcaf14 In Replication Fork Stability And Genome Integrity, Neysha Tirado-Class

USF Tampa Graduate Theses and Dissertations

The response to replication stress is critical for ensuring the stability of replication forks and preserving genome integrity. To aid this response, several factors are recruited to stalled replication forks to prevent irreversible collapse of the replication machinery. Replication fork proteomic analyses of stalled forks reveal enrichment of DCAF14, a component of the Cullin4-RING (CRL4) E3 ubiquitin ligase complex, that mediates replication fork protection by blocking nuclease-mediated digestion of nascent DNA. However, little is known about the molecular mechanism by which DCAF14 functions in the context of replication stress. Notably, loss of function mutations in DCAF14 are associated with a …

Group B Streptococcus Intestinal Barrier Disruption And The Protective Role Of Butyrate, Kristen Dominguez

USF Tampa Graduate Theses and Dissertations

Group B Streptococcus (Streptococcus agalactiae; GBS) is a leading cause of neonatal sepsis worldwide. Intrapartum antibiotics in GBS-colonized mothers significantly reduced the incidence of early-onset sepsis occurring in the first week of life; however, there are currently no prophylactic interventions for late-onset sepsis, occurring within the first 3 months of life. GBS is a pathobiont that primarily colonizes the gastrointestinal tract and can cross the intestinal barrier via both the paracellular and transcellular routes, causing invasive disease. Neonatal susceptibility to GBS intestinal translocation is mediated by inadequate epithelial barrier function and microbiome immaturity; however, the mechanisms by which GBS exploits …

A Homogeneous Time-Resolved Fluorescence Screen To Identify Sirt2 Deacetylase And Defatty-Acylase Inhibitors, Jie Yang, Joel Cassel, Brian C Boyle, Daniel Oppong, Young-Hoon Ahn, Brian P Weiser

Rowan-Virtua School of Osteopathic Medicine Departmental Research

Human sirtuin-2 (SIRT2) has emerged as an attractive drug target for a variety of diseases. The enzyme is a deacylase that can remove chemically different acyl modifications from protein lysine residues. Here, we developed a high-throughput screen based on a homogeneous time-resolved fluorescence (HTRF) binding assay to identify inhibitors of SIRT2's demyristoylase activity, which is uncommon among many ligands that only affect its deacetylase activity. From a test screen of 9600 compounds, we identified a small molecule that inhibited SIRT2's deacetylase activity (IC50 = 7 μM) as well as its demyristoylase activity (IC50 = 37 μM). The inhibitor was composed …

Adipose-Derived Mesenchymal Stem Cells And Their Derived Epidermal Progenitor Cells Conditioned Media Ameliorate Skin Aging In Rats, Mohamed M. Kamal, Omar Ibrahim Badr, Tasnim Mahmoud

Pharmacy

BACKGROUND: Skin alterations are among the most prominent signs of aging, and they arise from both intrinsic and extrinsic factors that interact and mutually influence one another. The use of D-galactose as an aging model in animals has been widely employed in anti-aging research. Adipose tissue-derived mesenchymal stem cells (Ad-MSCs) are particularly promising for skin anti-aging therapy due to their capacity for effective re-epithelization and secretion of various growth factors essential for skin regeneration. Accordingly, we aimed to examine the potential utility of Ad-MSCs as a therapy for skin anti-aging. METHODS: In this study, we isolated and characterized adipose-derived mesenchymal …

Enzymological Revisionism: Employing Transient State Approaches To Define The Catalytic Sequences Of Poorly Understood Systems, Madison M. Smith

Dissertations

Flavin is a molecule composed of a tricyclic isoalloxazine ring linked to a ribityl. Flavins are utilized as a cofactor by many enzymes to facilitate a myriad of chemistries. Flavoproteins were first discovered in the late 1800 s and have since been an interest to researchers, largely due to the unique spectrophotometric characteristics that make it a valuable reporter molecule. Flavin cofactors (typically either flavin adenine dinucleotide (FAD) or flavin mononucleotide (FMN)) are chemically versatile as the isoalloxazine ring can form one and two-electron reduced states. The reduced states are prone to react with molecular oxygen and numerous observations have …

Cellular Energy Cycle Mediates An Advection-Like Forward Cell Flow To Support Collective Invasion, Jian Zhang, Jenna Mosier, Yusheng Wu, Logan Waddle, Paul V. Taufelele, Wenjun Wang, Heng Sun, Cynthia A. Reinhart-King

Biomedical Engineering Faculty Publications and Presentations

Collective cell migration is a model for nonequilibrium biological dynamics, which is important for morphogenesis, pattern formation, and cancer metastasis. The current understanding of cellular collective dynamics is based primarily on cells moving within a 2D epithelial monolayer. However, solid tumors often invade surrounding tissues in the form of a stream-like 3D structure, and how biophysical cues are integrated at the cellular level to give rise to this collective streaming remains unclear. Here, it is shown that cell cycle-mediated bioenergetics drive a forward advective flow of cells and energy to the front to support 3D collective invasion. The cell division …

Cornus Officinalis Extract Activates The Keap1/Nrf2 Pathway And Delays T1d Onset In The Nod Mouse, Justin D. Fletcher

USF Tampa Graduate Theses and Dissertations

Type 1 diabetes (T1D) is an autoimmune disorder that results in the destruction of the insulin producing pancreatic β cells. The only therapeutic option following T1D clinical onset is exogenous insulin supplementation. At present, there is no cure for T1D and attempted interventional therapy has been focused on modulating the immune system. Few attempts have been pursued at preserving β cell function and survival. Here we provide a novel approach using extract from the fruit of the Cornus officinalis (CO) tree to preserve β cell function through the prevention of β cell stress. CO has been used in traditional Chinese …

Structural And Biophysical Insights Into Targeting Of Claudin-4 By A Synthetic Antibody Fragment, Satchal K. Erramilli, Pawel K. Dominik, Chinemerem P. Ogbu, Anthony A. Kossiakoff, Alex J. J.

Department of Biochemistry: Faculty Publications

Claudins are a 27-member family of ~25 kDa membrane proteins that integrate into tight junctions to form molecular barriers at the paracellular spaces between endothelial and epithelial cells. As the backbone of tight junction structure and function, claudins are attractive targets for modulating tissue permeability to deliver drugs or treat disease. However, structures of claudins are limited due to their small sizes and physicochemical properties—these traits also make therapy development a challenge. Here we report the development of a synthetic antibody fragment (sFab) that binds human claudin-4 and the determination of a high-resolution structure of it bound to claudin-4/enterotoxin complexes …

Investigation Of Self-Assembly Of Hen Egg White Lysozyme Fibrils, Nabila Bushra

USF Tampa Graduate Theses and Dissertations

Amyloid proteins are a large group of proteins that tend to aggregate and form insoluble fibrils with a characteristic cross-β sheet structure. Intriguingly, this process of “amyloid formation” has been simultaneously linked to devastating human diseases called amyloidoses, ranging from Alzheimer’s Disease, cardiac amyloidoses to type II diabetes, as well as functional biological responses such as hormone storage and sperm quality control. Amyloid fibrils have also attracted significant attention for their unique mechanical, chemical, and optical characteristics, establishing them as promising tough biomaterials. The urgent need to find treatments for Alzheimer’s disease, and the demand for safe and renewable biomaterials …

The Role Of Edc3 In Drosophila Melanogaster Neuronal Development, Keelan Zius

Electronic Theses and Dissertations

Enhancer of mRNA-decay 3 (Edc3) is a component of multiple decapping complexes that regulates the transcriptome by targeting a subset of transcripts for decapping for 5’-to-3’ messenger RNA (mRNA) decay. A missense mutation in the conserved Lsm domain of Edc3 has been reported in two siblings presenting with mild, non-syndromic intellectual disability (ID), however, the role of Edc3 is neuronal development has never been evaluated. Here, we use the Drosophila melanogaster model system to investigate the effects of Edc3 disruption on neuronal development. We found Edc3 reduction leads to significant hyperplasia at the larval neuromuscular junction (NMJ), providing the first …

Colocalization Of Odc And Amyloid Plaques In Patients With Alzheimer’S Disease And Down Syndrome, Julia S. Gielczynski

Undergraduate Theses, Capstones, and Recitals

Polyamines, and their rate-limiting enzyme ornithine decarboxylase (ODC), are crucial for many functions in the central nervous system but levels decrease with age. In neurodegenerative diseases, like Alzheimer’s Disease (AD), polyamine levels begin to increase again. Yet, there are still many unanswered questions surrounding polyamine’s possible role in AD, especially in those with Down Syndrome (DS), who also have an extra copy of the amyloid precursor protein (APP) and tend to get AD far earlier than the general population. We aim to investigate if there is colocalization between amyloid plaques and Ornithine Decarboxylase (ODC) in patients with AD and AD/DS, …

Characterization Of Oxidized Tau Protein Aggregation And Inhibition Of Tau Aggregation Via Map2, Brad Krzesinski

Electronic Theses and Dissertations

Neurofibrillary tangles (NFT) composed of the microtubule stabilizing protein Tau are a pathological hallmark of Alzheimer's disease (AD) and many other dementia related diseases specified as Tauopathies. Due to alternative mRNA splicing, intrinsically disordered Tau exists as six separate isoforms in the adult human brain where they are categorized by the lack or inclusion of the second repeat in the microtubule binding domain (3R or 4R respectively). Isoforms are subcategorized by the inclusion or lack thereof, one or two N-terminal inserts. Many studies show that Tau aggregates into amyloid fibrils and these fibrils can break into small oligomeric units known …

Morphological Remodeling Of The Endoplasmic Reticulum During Mitosis And Its Influence On The Integrity Of The Spindle Apparatus, Katie R. Rollins

Electronic Theses and Dissertations

The Endoplasmic Reticulum (ER) is the largest organelle in the cell by surface area and forms contacts with other organelles throughout the cell. In recent work, the ER has been implicated in numerous processes within the cell beyond its canonical roles of protein synthesis and calcium storage. The ER also undergoes a remarkable transition in morphology during cell division, with mitotic divisions requiring a massive remodeling of various membranous organelles such as the nuclear envelope and Golgi. However, whether changes in ER behaviors modulate mitotic events is less clear. The rapid cleavage divisions in the early Drosophila embryo are a …

Effect Of Plumbagin On Chemo-Resistant Metastatic Retinoblastoma, John J. Soto

Theses and Dissertations

Retinoblastoma, which is an ocular malignancy, usually results in poor prognoses in pediatric patients worldwide. Retinoblastoma in some events, can develop metastatic phenotypes which can lead to secondary tumor formation, furthering deleterious patient outcomes. It is of paramount importance to identify and research potent novel compounds that can be used to increase the likelihood of remission. Plumbagin (PLB) is a plant-derived, neuroprotective agent, which exhibits significant anticancer activities during in vitro study. PLB has been shown to have a high therapeutic efficacy against chemoresistant sublines as well as their normal counterparts. We attempted to show that the chemoresistant ABCC1 could …

Perspectives On Computational Modeling Of Biological Systems And The Significance Of The Sysmod Community, Bhanwar Lal Puniya, Meghna Verma, Chiara Damiani, Shaimaa Bakr, Andreas Dräger

Department of Biochemistry: Faculty Publications

Motivation: In recent years, applying computational modeling to systems biology has caused a substantial surge in both discovery and practical applications and a significant shift in our understanding of the complexity inherent in biological systems.

Results: In this perspective article, we briefly overview computational modeling in biology, highlighting recent advancements such as multiscale modeling due to the omics revolution, single-cell technology, and integration of artificial intelligence and machine learning approaches. We also discuss the primary challenges faced: integration, standardization, model complexity, scalability, and interdisciplinary collaboration. Lastly, we highlight the contribution made by the Computational Modeling of Biological Systems …

Scanless Two-Photon Voltage Imaging, Ruth R Sims, Imane Bendifallah, Christiane Grimm, Aysha S Mohamed Lafirdeen, Soledad Domínguez, Chung Yuen Chan, Xiaoyu Lu, Benoît C Forget, François St-Pierre, Eirini Papagiakoumou, Valentina Emiliani

Faculty, Staff and Students Publications

Two-photon voltage imaging has long been heralded as a transformative approach capable of answering many long-standing questions in modern neuroscience. However, exploiting its full potential requires the development of novel imaging approaches well suited to the photophysical properties of genetically encoded voltage indicators. We demonstrate that parallel excitation approaches developed for scanless two-photon photostimulation enable high-SNR two-photon voltage imaging. We use whole-cell patch-clamp electrophysiology to perform a thorough characterization of scanless two-photon voltage imaging using three parallel illumination approaches and lasers with different repetition rates and wavelengths. We demonstrate voltage recordings of high-frequency spike trains and sub-threshold depolarizations from neurons …

Ancient Nitrogenases Are Atp Dependent, Derek F. Harris, Holly R. Rucker, Amanda K. Garcia, Zhi-Yong Yang, Scott D. Chang, Hannah Feinsilber, Betül Kaçar, Lance C. Seefeldt

Chemistry and Biochemistry Faculty Publications

Life depends on a conserved set of chemical energy currencies that are relics of early biochemistry. One of these is ATP, a molecule that, when paired with a divalent metal ion such as Mg²⁺, can be hydrolyzed to support numerous cellular and molecular processes. Despite its centrality to extant biochemistry, it is unclear whether ATP supported the function of ancient enzymes. We investigate the evolutionary necessity of ATP by experimentally reconstructing an ancestral variant of the N₂-reducing enzyme nitrogenase. The Proterozoic ancestor is predicted to be ~540–2,300 million years old, post-dating the Great Oxidation Event. Growth …

Incorporating Oxygen Isotopes Of Oxidized Reactive Nitrogen In The Regional Atmospheric Chemistry Mechanism, Version 2 (Icoin-Racm2), Wendell W. Walter, Masayuki Takeuchi, Nga L. Ng, Meredith G. Hastings

Faculty Publications

The oxygen isotope anomaly (Δ¹⁷O = δ¹⁷O − 0.52 × δ¹⁸O > 0) has proven to be a robust tool for probing photochemical cycling and atmospheric formation pathways of oxidized reactive nitrogen (NO_y). Several studies have developed modeling techniques to implicitly model Δ¹⁷O of NO_y molecules based on numerous assumptions that may not always be valid. Thus, these models may be oversimplified and limit our ability to compare model Δ¹⁷O values of NO_y with observations. In this work, we introduce a novel method for explicitly tracking Δ …