Biochemistry, Biophysics, and Structural Biology Commons^™

Structural And Biochemical Investigations Of The Initiation Of Dna Replication In Bacteriophage Lambda And Escherichia Coli, Jillian D. Chase

Dissertations, Theses, and Capstone Projects

Faithful transmission of genetic information is requisite for the propagation of all life. DNA replication in each of the three domains of life requires the separation of double stranded DNA (dsDNA) into single stranded DNA (ssDNA) which then serves as a template for genomic duplication of each original DNA strand. Initiation of replication events occurs by tightly regulated processes during which specialized proteins are loaded at a specific locus within the genome, termed the origin of replication, in preparation of bidirectional replication events. A replicative helicase must be loaded or assembled on both strands of DNA at the origin to …

Paddling Along The Voltage Gated Sodium Channel Galaxy With Sea Anemone Toxins: Structural Studies Of The Interaction Between The Paddle Motif From Nav1.5div And Sea Anemone Toxin, Adel K. Hussein

Dissertations, Theses, and Capstone Projects

Voltage gated sodium channels (VGSC) are membrane proteins that serve an important function in the central nervous system (CNS), peripheral nervous system (PNS), and cardiac muscles amongst others. The main function of VGSC is in the propagation of electrical signals by depolarizing excitable cells. Nine mammalian VGSC subtypes have been characterized, Na_V1.1 – Na_V1.9, that are expressed in a tissue specific manner, each with unique gating properties. Numerous diseases have been linked to defects in VGSC including epilepsy, mental retardation, long QT syndrome, and Brugada disease. Furthermore, these channels are one of the primary targets of …

Water-Based Lead Generation, Brian Olson

Dissertations, Theses, and Capstone Projects

Water-based Lead Generation. The opioid epidemic and the SARS-CoV-2 pandemic are current serious challenges whose devastating effects could be assuaged through the development of new drugs. Opioids that are functional painkillers, that are less likely to cause overdose, and small molecule drugs that could inhibit the life cycle of SARS-CoV-2 would be useful. The work herein investigated the use of water molecules for lead generation in drug development against opioid receptors and SARS-CoV-2 viral proteins. In opioid receptor binding sites, purported bridging waters were obtained from crystal waters or from molecular dynamics simulations, as Hydration Site Analysis was used to …

An In Silico Approach To Investigate The Structural And Biochemical Basis Of The Rna Binding Functions Of Nucleolin, Avdar San

Dissertations, Theses, and Capstone Projects

Nucleolin (NCL) is a stress responsive multifunctional nucleolar protein and accounts for 10% of the total nucleolar protein content. NCL belongs to the class of RNA binding proteins (RBPs) that regulate many important cellular processes through their interactions with different RNA molecules. The dysregulation of RBPs and the RNA metabolism pathways they intersect is a known driver of tumorigenesis. NCL regulates ribosome biogenesis, chromatin remodeling, microRNA processing, and gene expression on multiple levels. The RNA-protein interactions of NCL are primarily driven by its four RNA binding domains (RBDs). NCL is known to interact with a growing list of primary-miRNA (pri-miRNA) …

Histone Post-Translational Modification Dysregulation Contributes To Toxicity In Amyotrophic Lateral Sclerosis Proteinopathy Models, Seth A. Bennett

Dissertations, Theses, and Capstone Projects

Amyotrophic Lateral Sclerosis (ALS) is the third most common adult onset neurodegenerative disorder worldwide. It is generally characterized by progressive paralysis starting at the limbs ultimately leading to death caused by respiratory failure. There is no cure and current treatments fail to slow the progression of the disease. As such, new treatment options are desperately needed. Epigenetic targets are an attractive possibility because they are reversible. Epigenetics refers to heritable changes in gene expression unrelated to changes in DNA sequence. Histone modifications, a main epigenetic mechanism, occur in many amino acid residues and include phosphorylation, acetylation, methylation as well as …

Role Of Metals In Human Immune System: Study Of Metal-Dependent Structural Changes Of S100a12 Protein, Aleksey Aleshintsev

Dissertations, Theses, and Capstone Projects

S100A12 protein belongs to the S100 family of calcium-binding proteins and participates in the innate immune system. Antimicrobial proteins from the S100 family of the proteins (S100A12, S100A8/A9, etc.) are secreted and expressed by neutrophils during microbial infection and perform their antimicrobial activity through metal sequestration. While most S100 proteins function intracellularly, S100A12 is highly expressed and secreted into the extracellular space by neutrophils during infection. Sequestration of Zn²⁺ by S100A12 is aided by the nanomolar zinc binding affinity of the protein at neutral pH conditions, which is further enhanced upon calcium-binding. The Zn²⁺ binding scaffold in S100A12 …

Maternal Choline Supplementation And High-Fat Feeding Interact To Influence Dna Methylation In Offspring In A Time-Specific Manner, Hunter W. Korsmo, Bhoomi Dave, Steven E. Trasino, Anjana Saxena, Jia Liu, Jorge Matias Caviglia, Kaydine Edwards, Moshe Dembitzer, Shameera Sheeraz, Sarah Khaldi, Xinyin Jiang

Advanced Science Research Center

Maternal methyl donor supplementation during pregnancy has demonstrated lasting influence on offspring DNA methylation. However, it is unknown whether an adverse postnatal environment, such as high-fat (HF) feeding, overrides the influence of prenatal methyl donor supplementation on offspring epigenome. In this study, we examined whether maternal supplementation of choline (CS), a methyl donor, interacts with prenatal and postnatal HF feeding to alter global and site-specific DNA methylation in offspring. We fed wild-type C57BL/6J mouse dams a HF diet with or without CS throughout gestation. After weaning, the offspring were exposed to HF feeding for 6 weeks resembling a continued obesogenic …

Glycocalyx Mechanotransduction Mechanisms Are Involved In Renal Cancer Metastasis, Heriberto Moran, Limary M. Cancel, Peigen Huang, Sylvie Roberge, Tuoye Xu, John M. Tarbell, Lance L. Munn

Publications and Research

Mammalian cells, including cancer cells, are covered by a surface layer containing cell bound proteoglycans, glycoproteins, associated glycosaminoglycans and bound proteins that is commonly referred to as the glycocalyx. Solid tumors also have a dynamic fluid microenvironment with elevated interstitial flow. In the present work we further investigate the hypothesis that interstitial flow is sensed by the tumor glycocalyx leading to activation of cell motility and metastasis. Using a highly metastatic renal carcinoma cell line (SN12L1) and its low metastatic counterpart (SN12C) we demonstrate in vitro that the small molecule Suberoylanilide Hydroxamic Acid (SAHA) inhibits the heparan sulfate synthesis enzyme …

Principles Of General Chemistry, Jose Cobo

Open Educational Resources

No abstract provided.

Preparation For General Chemistry, Jose Cobo

Open Educational Resources

No abstract provided.

Protein Charge Parameters That Influence Stability And Cellular Internalization Of Polyelectrolyte Complex Micelles, Rachel A. Kapelner, Rachel S. Fisher, Shana Elbaum-Garfinkle, Allie C. Obermeyer

Advanced Science Research Center

Proteins are an important class of biologics, but there are several recurring challenges to address when designing protein-based therapeutics. These challenges include: the propensity of proteins to aggregate during formulation, relatively low loading in traditional hydrophobic delivery vehicles, and inefficient cellular uptake. This last criterion is particularly challenging for anionic proteins as they cannot cross the anionic plasma membrane. Here we investigated the complex coacervation of anionic proteins with a block copolymer of opposite charge to form polyelectrolyte complex (PEC) micelles for use as a protein delivery vehicle. Using genetically modified variants of the model protein green fluorescent protein (GFP), …

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 …

Reproducibility Of Individual Dna Deposits Detected Through Cellular Fluorescence, Natalee Small-Davidson

Student Theses

Contact traces are an important part of DNA casework, but the probative value of any identified associations depends on the possibility of passive transfer. There is known individual variation in DNA left behind during contact, this DNA shedding propensity has an effect on whose DNA is detected. This study evaluated this variability using a cell staining approach. Volunteers were asked to deposit a fingerprint on a clean glass slide, then wash their hands and deposit a second fingerprint after a 30-minute wait without touching anything. Three sets of samples were collected over three consecutive weeks. Fingerprints were stained with a …

High-Resolution Cryo-Electron Microscopy Structure Of Photosystem Ii From The Mesophilic Cyanobacterium, Synechocystis Sp. Pcc 6803, Christopher J. Gisriel, Jimin Wang, Jinchan Liu, David A. Flesher, Krystle M. Reiss, Hao-Li Huang, Ke R. Yang, William H. Armstrong, M. R. Gunner, Victor S. Batista, Richard J. Debus, Gary W. Brudvig

Publications and Research

Photosystem II (PSII) enables global-scale, light-driven water oxidation. Genetic manipulation of PSII from the mesophilic cyanobacterium Synechocystis sp. PCC 6803 has provided insights into the mechanism of water oxidation; however, the lack of a highresolution structure of oxygen-evolving PSII from this organism has limited the interpretation of biophysical data to models based on structures of thermophilic cyanobacterial PSII. Here, we report the cryo-electron microscopy structure of PSII from Synechocystis sp. PCC 6803 at 1.93-Å resolution. A number of differences are observed relative to thermophilic PSII structures, including the following: the extrinsic subunit PsbQ is maintained, the C terminus of the …

Cryptococcus Neoformans Melanization Incorporates Multiple Catecholamines To Produce Polytypic Melanin, Rosanna P. Baker, Christine Chrissian, Ruth E. Stark, Arturo Casadevall

Publications and Research

Melanin is a major virulence factor in pathogenic fungi that enhances the ability of fungal cells to resist immune clearance. Cryptococcus neoformans is an important human pathogenic fungus that synthesizes melanin from exogenous tissue catecholamine precursors during infection, but the type of melanin made in cryptococcal meningoencephalitis is unknown. We analyzed the efficacy of various catecholamines found in brain tissue in supporting melanization using animal brain tissue and synthetic catecholamine mixtures reflecting brain tissue proportions. Solid-state NMR spectra of the melanin pigment produced from such mixtures yielded more melanin than expected if only the preferred constituent dopamine had been incorporated, …

Discovery Of Phosphotyrosine-Binding Oligopeptides With Supramolecular Target Selectivity, Ana S. Pina, Leonor Morgado, Krystyna L. Duncan, Sara Carvalho, Henrique F. Carvalho, Armenio J. M. Barbosa, Beatriz De P. Mariz, Ines P. Moreira, Daniela Kalafatovic, Bruno M. Morais Faustino, Vishal Narang, Tong Wang, Charalampos G. Pappas, Isabel Ferreira, A. Cecılia A. Roque, Rein V. Ulijn

Advanced Science Research Center

We demonstrate phage-display screening on self-assembled ligands that enables the identification of oligopeptides that selectively bind dynamic supramolecular targets over their unassembled counterparts. The concept is demonstrated through panning of a phage-display oligopeptide library against supramolecular tyrosine-phosphate ligands using 9-fluorenylmethoxycarbonyl-phenylalanine-tyrosine-phosphate (Fmoc-FpY) micellar aggregates as targets. The 14 selected peptides showed no sequence consensus but were enriched in cationic and proline residues. The lead peptide, KVYFSIPWRVPM-NH2 (P7) was found to bind to the Fmoc-FpY ligand exclusively in its self-assembled state with KD = 74 ± 3 μM. Circular dichroism, NMR and molecular dynamics simulations revealed that the peptide interacts with Fmoc-FpY …

Development And Validation Of A Method For The Determination Of Designer Benzodiazepines In Hair By Liquid Chromatography Tandem Mass Spectrometry (Lc-Ms/Ms), Laura C. Defreitas

Student Theses

In recent years, new designer benzodiazepines have become a challenge in forensic toxicology. These substances are analogues of the classic benzodiazepines, but their pharmacology is not well known, and many of them have been associated with overdoses and deaths. As a result, there has been a surge in efforts to develop ways to accurately test for these compounds in different biological matrices. This study focused to develop and validate a method for determining 17 new designer benzodiazepines in hair by liquid chromatography tandem mass spectrometry (LC-MS/MS). Hair samples were decontaminated, pulverized, and 20 mg of the sample was incubated in …

Living With A Giant, Flowering Parasite: Metabolic Differences Between Tetrastigma Loheri Gagnep. (Vitaceae) Shoots Uninfected And Infected With Rafflesia (Rafflesiaceae) And Potential Applications For Propagation, Jeanmaire Molina, Dejan Nikolic, Jashvanth Raaj Jeevarathanam, Rinat Abzalimov, Eun‑Jung Park, Ronniel Pedales, Elmer‑Rico E. Mojica, Danilo Tandang, William Mclaughlin, Kyle Wallick, James Adams, Ari Novy, Susan K. Pell, Richard B. Van Breemen, John M. Pezzuto

Advanced Science Research Center

Main conclusion: Metabolites in Rafflesia-infected and non-infected Tetrastigma were compared which may have applications in Rafflesia propagation. Benzylisoquinoline alkaloids, here reported for the first time in Vitaceae, were abundant in non-infected shoots and may be a form of defense. In Rafflesia-infected shoots, oxylipins, which mediate immune response, were elevated.

Endemic to the forests of Southeast Asia, Rafflesia (Rafflesiaceae) is a genus of holoparasitic plants producing the largest flowers in the world, yet completely dependent on its host, the tropical grape vine, Tetrastigma. Rafflesia species are threatened with extinction, making them an iconic symbol of plant conservation. Thus …

Structure Of A Monomeric Photosystem Ii Core Complex From A Cyanobacterium Acclimated To Far-Red Light Reveals The Functions Of Chlorophylls D And F, Christopher J. Gisriel, Gaozhong Shen, Ming-Yang Ho, Vasily Kurashov, David A. Flesher, Jimin Wang, William H. Armstrong, John H. Golbeck, Marilyn R. Gunner, David J. Vinyard, Richard J. Debus, Gary W. Brudvig, Donald A. Bryant

Publications and Research

Far-red light (FRL) photoacclimation in cyanobacteria provides a selective growth advantage for some terrestrial cyanobacteria by expanding the range of photosynthetically active radiation to include far-red/near-infrared light (700–800 nm). During this photoacclimation process, photosystem II (PSII), the water:plastoquinone photooxidoreductase involved in oxygenic photosynthesis, is modified. The resulting FRL-PSII is comprised of FRL-specific core subunits and binds chlorophyll (Chl) d and Chl f molecules in place of several of the Chl a molecules found when cells are grown in visible light. These new Chls effectively lower the energy canonically thought to define the “red limit” for light required to drive photochemical …

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, …

Expression, Purification And Refolding Of A Human Na V 1.7 Voltage Sensing Domain With Native-Like Toxin Binding Properties, Ryan V. Schroder, Leah S. Cohen, Ping Wang, Joekeem D. Arizala, Sébastien F. Poget

Publications and Research

The voltage-gated sodium channel NaV1.7 is an important target for drug development due to its role in pain perception. Recombinant expression of full-length channels and their use for biophysical characterization of interactions with potential drug candidates is challenging due to the protein size and complexity. To overcome this issue, we developed a protocol for the recombinant expression in E. coli and refolding into lipids of the isolated voltage sensing domain (VSD) of repeat II of NaV1.7, obtaining yields of about 2 mg of refolded VSD from 1 L bacterial cell culture. This VSD is known to be involved in the …

A Conserved Structural Role For The Walker-A Lysine In P-Loop Containing Kinases, Fatlum Hajredini, Ranajeet Ghose

Publications and Research

Bacterial tyrosine kinases (BY-kinases) and shikimate kinases (SKs) comprise two structurally divergent P-loop containing enzyme families that share similar catalytic site geometries, most notably with respect to their Walker-A, Walker-B, and DxD motifs. We had previously demonstrated that in BY-kinases, a specific interaction between the Walker-A and Walker-B motifs, driven by the conserved “catalytic” lysine housed on the former, leads to a conformation that is unable to efficiently coordinate Mg²⁺•ATP and is therefore incapable of chemistry. Here, using enhanced sampling molecular dynamics simulations, we demonstrate that structurally similar interactions between the Walker-A and Walker-B motifs, also mediated by …

Aurora Kinase A Inhibition Reverses The Warburg Effect And Elicits Unique Metabolic Vulnerabilities In Glioblastoma, Trang T. T. Nguyen, Enyuan Shang, Chang Shu, Sungsoo Kim, Angeliki Mela, Nelson Humala, Aayushi Mahajan, Hee Won Yang, Hasan Orhan Akman, Catarina M. Quinzii, Guoan Zhang, Mike-Andrew Westhoff, Georg Karpel-Massler, Jeffrey N. Bruce, Peter Canoll, Markus D. Siegelin

Publications and Research

Aurora kinase A (AURKA) has emerged as a drug target for glioblastoma (GBM). However, resistance to therapy remains a critical issue. By integration of transcriptome, chromatin immunoprecipitation sequencing (CHIP-seq), Assay for Transposase-Accessible Chromatin sequencing (ATAC-seq), proteomic and metabolite screening followed by carbon tracing and extracellular flux analyses we show that genetic and pharmacological AURKA inhibition elicits metabolic reprogramming mediated by inhibition of MYC targets and concomitant activation of Peroxisome Proliferator Activated Receptor Alpha (PPARA) signaling. While glycolysis is suppressed by AURKA inhibition, we note an increase in the oxygen consumption rate fueled by enhanced fatty acid oxidation (FAO), which was …

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 …

Study Of The Gain-Of-Function Mutant P53 And Parp1 In Triple-Negative Breast Cancer, Devon Lundine

Dissertations, Theses, and Capstone Projects

Cancer cells often lose expression of the p53 protein or express mutant forms of p53. Some of these mutant p53 proteins, called gain-of-function mutant p53, have gained oncogenic functions. Previously, our group observed mutant p53 R273H interacts with replicating DNA and upregulates the chromatin localization of several DNA replication factors including PCNA, MCM2-7, and PARP1 (termed the mtp53-PARP-MCM axis). In this thesis, we explore the contribution of mutant p53 and PARP1 in castration-resistant prostate cancer (mutant p53 P223L and V274F) and triple-negative breast cancer (mutant p53 R273H). In the castration-resistant prostate cancer cell line DU145, we examine two mutant p53 …

Understanding The Influence Of Zinc On Grain Cadmium Accumulation And Bioaccessibility In Rice, Michael A. Tavarez

Dissertations, Theses, and Capstone Projects

The effect of cadmium and zinc on mineral concentrations in three cultivars of rice

Interactions between the essential mineral zinc (Zn) and the toxic heavy metal cadmium (Cd) play an important role in regulating transport of both minerals to rice grains. Understanding these interactions is crucial for limiting cadmium and increasing zinc transfer to the food chain. Previous studies on the matter have had conflicting results suggesting synergistic and antagonistic relationships between the minerals. The goal of this work was to identify the effect of external cadmium and zinc on the uptake and translocation of both minerals from roots to …

The Structural And Functional Role Of Photosensing In Rgs-Lov Proteins, Zaynab Jaber

Dissertations, Theses, and Capstone Projects

Light provides organisms with energy and spatiotemporal information. To survive and adapt, organisms have developed the ability to sense light to drive biochemical effects that underlie vision, entrainment of circadian rhythm, stress response, virulence, and many other important molecularly driven responses. Blue-light sensing Light-Oxygen-Voltage (LOV) domains are ubiquitous across multiple kingdoms of life and modulate various physiological events via diverse effector domains. Using a small molecule flavin chromophore, the LOV domain undergoes light-dependent structural changes leading to activation or repression of these catalytic and non-catalytic effectors. In silico analyses of high-throughput genomic sequencing data has led to the marked expansion …

The Role Of Estrogen Receptor Alpha In Regulating Messenger Rna 3’ End Processing And Controlling Gene Expression In Breast Cancer Cells, Sophia Varriano

Dissertations, Theses, and Capstone Projects

Estrogen signaling regulates various physiological processes within the female reproductive, cardiovascular, immune, and central nervous systems and is predominantly mediated by estrogen receptors (ER), ERα and ERβ. Transcriptional regulation by ERs has been widely studied, where activated ERs bind either directly to target genes through binding to estrogen response elements or indirectly through interacting with other proteins, resulting in changes in gene expression. However, the potential role of factors involved in the estrogen signaling pathway in posttranscriptional regulation has not been extensively documented. As 70-80% of breast cancers (BCs) are identified as ER(+), studying how these factors, particularly ERα, regulates …

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 …

Dual Control Of One Component Signaling: Mechanistic And Structural Insights Into El222 Active States, Uthama Phani R. Edupuganti

Dissertations, Theses, and Capstone Projects

Photoreceptors play a crucial role in signal transduction as specialized proteins which sense light as environmental stimuli and transduce the signal to control of downstream functions. Here we focus our attention on one class of these proteins, the Light-Oxygen-Voltage (LOV) domain, which is sensitive to blue light via an internally-bound flavin chromophore. Since their initial discovery in plant phototropins, many details of their photochemistry, chromophore interactions, and use with a diverse set of functional effectors have been described. However, several key details, especially a comprehensive understanding of signaling mechanism and its regulation, still remain elusive due in part to the …