Biochemistry Commons^™

Redox Active Motifs In Selenoproteins, Fei Li, Yuliya Pepelyayeva, Elias S. J. Arner, Craig A. Bayse, Sharon Rozovsky

Chemistry & Biochemistry Faculty Publications

Selenoproteins use the rare amino acid selenocysteine (Sec) to act as the first line of defense against oxidants, which are linked to aging, cancer, and neurodegenerative diseases. Many selenoproteins are oxidoreductases in which the reactive Sec is connected to a neighboring Cys and able to form a ring. These Sec-containing redox motifs govern much of the reactivity of selenoproteins. To study their fundamental properties, we have used Se-77 NMR spectroscopy in concert with theoretical calculations to determine the conformational preferences and mobility of representative motifs. This use of Se-77 as a probe enables the direct recording of the properties of …

Tht And Capillary Electrophoresis To Monitor The Effects Of Solutions Conditions On Amylin Aggregation, Michael May

Graduate Theses and Dissertations

Amylin (hIAPP) aggregates have been found in 90% of patients with type II diabetes at autopsy, and are suspected to play a role in the death of islet &beta-cells¹. However, this aggregation process is not well understood. Here, we explore methods that utilize capillary electrophoresis (CE) as a means to better understand amylin's aggregation process.

We examined the effects of solutions conditions: agitation, pH, salt, and temperature on amylin aggregation using Thioflavin T, dot blots, and capillary electrophoresis. Thiofalvin T was used to predict the lag time to &beta-sheet formation. Our results indicated all variables with the exception …

Metal Stopping Reagents Facilitate Discontinuous Activity Assays Of The De Novo Purine Biosynthesis Enzyme Pure, Kelly L. Sullivan, Loredana C. Huma, Elwood Mullins, Michael E. Johnson, T. Joseph Kappock

Department of Biochemistry Faculty Publications

The conversion of 5-aminoimidazole ribonucleotide (AIR) to 4-carboxy-AIR (CAIR) represents an unusual divergence in purine biosynthesis: microbes and nonmetazoan eukaryotes use class I PurEs while animals use class II PurEs. Class I PurEs are therefore a potential antimicrobial target; however, no enzyme activity assay is suitable for high throughput screening (HTS). Here we report a simple chemical quench that fixes the PurE substrate/product ratio for 24 h, as assessed by the Bratton-Marshall assay (BMA) for diazotizable amines. The ZnSO₄ stopping reagent is proposed to chelate CAIR, enabling delayed analysis of this acid-labile product by BMA or other HTS methods

Characterization Of Udp-Arabinopyranose Mutase Genes In The Arabidopsis Cell Wall Mutant Mur5, Christopher A. Hart

Honors Scholar Theses

The genome of Arabidopsis thaliana contains several coding regions for UDP-arabinopyranose mutases (UAMs) that are also known as reversibly glycosylated polypeptides (RGPs). The mur5 cell wall mutant of Arabidopsis shows a 30% decrease in cell wall arabinose content, and a missense mutation in the Reversibly Glycosylated Polypeptide 2 gene was recently proposed to cause this mutant phenotype. Through a traditional complementation analysis, mur5 and a T-DNA insertion mutant in the RGP2 gene were shown not to complement each other, indicating that the two genes are mutant alleles of the same locus. The mur5 SNP located in RGP2 caused a more …

Modeling The Adaptive Immune Response To Mutation-Generated Antigens, Rory J. Geyer

Honors Scholar Theses

Somatic mutations may drive tumorigenesis or lead to new, immunogenic epitopes (neoantigens). The immune system is thought to represses neoplastic growths through the recognition of neoantigens presented only by tumor cells. To study mutations as well as the immune response to mutation-generated antigens, we have created a conditional knockin mouse line with a gene encoding, 5’ to 3’, yellow fluorescent protein (YFP), ovalbumin (which is processed to the immunologically recognizable peptide, SIINFEKL), and cyan fluorescent protein (CFP), or, YFP-ovalbumin-CFP. A frame shift mutation has been created at the 5’ end of the ovalbumin gene, hence YFP should always be expressed, …

Functional Analysis Of Cytosolic Hsp70 Nucleotide Exchange Factor Networks In Yeast, Jennifer Lynn Abrams

Dissertations and Theses (Open Access)

The Hsp70 class of molecular chaperones play critical roles in protein homeostasis via an ATP-dependent folding cycle. Cytosolic Hsp70s in the budding yeast Saccharomyces cerevisiae, Ssa and Ssb, interact with up to three distinct nucleotide exchange factors (NEFs) homologous to human counterparts; Sse1/Sse2/HSP110, Fes1/HspBP1, and Snl1/Bag1. In an effort to understand the differential functional contributions of the cytosolic NEFs to protein homeostasis (“proteostasis”), I carried out comparative genetic, biochemical and cell biological analyses. For these studies, I developed protocols to monitor protein disaggregation and reactivation in a near real-time coupled assay that revealed the importance of aggregate dynamics in the …

Pop2: A Potential Regulator Of Hmt1-Catalyzed Arginine Methylation In Yeast, Celeste Excell

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Protein arginine methylation is an important post-translational modification that is vital in regulating various cellular processes such as gene transcription, cell signaling, and RNA processing. Protein arginine methyltransferases (PRMTs) are responsible for performing this important modification. PRMT1 (protein arginine methyltransferase 1) and Hmt1 (hnRNP methyltransferase 1) are the predominant PRMTs in humans and yeast, respectively. Despite growing momentum in this field, relatively little is understood about PRMT regulation. Further work discovering how PRMTs are regulated will greatly advance our understanding of diseases where PRMTs have been implicated, such as heart disease, viral pathogenesis, and cancer.

It has been discovered that …

Electron Transfer And Substrate Reduction In Nitrogenase, Karamatullah Danyal

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The reduction of nitrogen to ammonia by the industrial Haber-Bosch process is considered one of the major scientific breakthroughs of the last century. It is considered to be responsible for approximately one third of the world's current population. This growth over the past 50 or so years accompanied by the changes in dietary habits due to economic growth have markedly increased the demand for fixed nitrogen in the form of fertilizer. The Haber-Bosch process and biological nitrogen fixation has been able to fulfil this demand. However, this industrial process is costly due to its high temperature and pressure requirements. Every …

Mechanisms Of Action And Co-Optive Evolution For Hypervariable Courtship Pheromones In Plethodontid Salamanders., Wilburn Beau Wilburn

Electronic Theses and Dissertations

Pheromones are an important type of chemical cue used by most animals to convey information between individuals. For more than 100 million years, male plethodontid salamanders have utilized a system of non-volatile, proteinaceous pheromones to regulate female mating behavior and receptivity. One of these pheromone components, Plethodontid Modulating Factor (PMF), is a hypervariable protein related to the three-finger protein (TFP) superfamily. Previous studies revealed that PMF persists as a rapidly evolving multi-isoform mixture. However, many characteristics of PMF as a pheromone remained undetermined, including gene structure and transcriptional regulation, translational regulation, protein structure, evolutionary mechanisms, and the isoform effects on …

Augmentation Of Ras-Induced Cell Transformation : A New Role For Mir-200a In Malignancy., Lindsey Erin Becker

Electronic Theses and Dissertations

Cancer is a multistep disease that begins with malignant cell transformation and frequently culminates in metastasis and death. MicroRNAs (miRNAs) are small regulatory 21-25-nt RNA molecules and are frequently deregulated in cancer. The majority of miRNAs are estimated to be co-expressed with neighboring miRNAs as clusters. Many miRNA clusters coordinately regulate multiple members of cellular signaling pathways or protein interaction networks. miR-200a is a member of the miR-200 family, which are known to be strong inhibitors of the epithelial to mesenchymal transition. As such, the tumor suppressive role of miR-200a in oncogenesis has been well studied; however, recent studies have …

Initial Characterization Of A Conserved Active Site Residue For The Cdc34 Ubiquitin Conjugating Enzyme, Arvin Akoopie

Honors College Theses

Ubiquitin-conjugating enzymes (E2s) covalently modify protein substrates with ubiquitins. The active site cysteine residues on E2s are essential for catalyzing the transfer of ubiquitin from the E2 active site onto the protein substrate, however there is a limited amount of information available concerning additional active site residues for E2s that may also participate in catalysis. Cdc34 is an essential E2 that has merited the lion’s share of attention for biochemical analysis of the E2 family. Previous phylogenetic analysis of Cdc34 amino acid sequences has identified an invariably conserved histidine residue close to the active site cysteine in the primary structure, …

Characterization Of Ftsa-Ftsn Interaction During Escherichia Coli Cell Division, [email protected] K. Busiek

Dissertations and Theses (Open Access)

Division of a bacterial cell into two equal daughter cells requires precise assembly and constriction of the division machinery, or divisome. The Escherichia coli divisome includes nearly a dozen essential cell division proteins that assemble at midcell between segregating sister chromosomes. FtsZ, a homolog of eukaryotic tubulin, is the first essential cell division protein to localize at midcell where it polymerizes into a ring-shaped scaffold (Z ring). Establishment of the Z ring is required for recruitment of downstream cell division proteins including FtsA, a cytoplasmic protein that tethers the Z ring to the inner membrane. Following localization of FtsA and …

Diabetes And Obesity Induce Transcriptomic And Metabolomic Changes Enhancing Pancreatic Cancer Aggressiveness, Guermarie Velázquez Torres

Dissertations and Theses (Open Access)

Pancreatic cancer is one of the most aggressive types of cancer, with poor prognosis that lacks effective diagnostic markers and therapies. It is expected that in 2014 the incidence and the mortality of pancreatic cancer in the United States will be 46,420 and 39,590 respectively. Diabetes and obesity are modifiable risk factors associated with accelerated pancreatic carcinogenesis and tumor progression, but the biological mechanisms are not completely understood. The purpose of this study is to demonstrate direct evidence for the mechanisms mediating these epidemiologic phenomena. Our hypothesis is that obesity and diabetes mellitus type 2 (DM2) accelerate pancreatic cancer and …

Clpxp Modulates Cell Growth And Morphology In Cell Shape Mutants Of E.Coli, Ryann Murphy

Senior Honors Projects

ClpXP modulates cell growth and morphology in cell shape mutants of E. coli

Ryann Murphy¹ and Jodi L. Camberg¹

¹University of Rhode Island, Department of Cell and Molecular Biology, Kingston, RI, 02881

Penicillin Binding Proteins (PBPs) are a family of prokaryotic membrane proteins named for their propensity to bind the antibiotic penicillin and are involved in remodeling and deposition of peptidoglycan. In wild type Escherichia coli cells, the uniform rod shape is conserved across generations. E.coli cells containing multiple deletions of Low Molecular Weight (LMW) PBPs exhibit irregular shapes. LMW PBP5 (dacA) is a potential …

Quantum Mechanical Study Of Weak Molecular Interactions, Upendra Adhikari

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Molecular interactions play key role in the existence of biomolecules like proteins and nucleic acids, and various materials. Molecular interactions are weak forces that hold different molecules or different fragments of the same molecule together, and are often referred to as noncovalent interactions. Due to the complexity in biomolecules, these interactions are still poorly understood. This dissertation presents results from quantum mechanical simulations of various types of noncovalent interactions, which are extremely important for the structure and functions of biomolecules and materials.

A new sort of noncovalent interaction is identified. This new sort of interaction originates from a direct interaction …

Structure-Based Design Of Novel Inhibitors And Ultra High Resolution Analysis Of Ctx-M Beta-Lactamase, Derek Allen Nichols

USF Tampa Graduate Theses and Dissertations

The emergence of CTX-M class-A extended-spectrum β-lactamases, which confer resistance to second and third-generation cephalosporins, poses a serious health threat to the public. CTX-M β-lactamases use a catalytic serine to hydrolyze the β-lactam ring. Specifically, the hydrolysis reaction catalyzed by CTX-M β-lactamase proceeds through a pre-covalent complex, a high-energy tetrahedral acylation intermediate, a low-energy acyl-enzyme complex, a high-energy tetrahedral deacylation intermediate after attack via a catalytic water, and lastly, the hydrolyzed β-lactam ring product which is released from the enzyme complex. The crystallographic structure of CTX-M at sub-angstrom resolution has enabled us to study enzyme catalysis as well as perform …

Antimicrobial And Antiinsectan Phenolic Metabolites Of Dalea Searlsiae, Gil Belofsky, Mario Aronica, Eric Foss, Jane Diamond, Felipe Santana, Jacob Darley, Patrick F. Dowd, Christina M. Coleman, Daneel Ferreira

All Faculty Scholarship for the College of the Sciences

Continued interest in the chemistry of Dalea spp. led to investigation of Dalea searlsiae, a plant native to areas of the western United States. Methanol extractions of D. searlsiae roots and subsequent chromatographic fractionation afforded the new prenylated and geranylated flavanones malheurans A–D (1–4) and known flavanones (5 and 6). Known rotenoids (7 and 8) and isoflavones (9 and 10) were isolated from aerial portions. Structure determination of pure compounds was accomplished primarily by extensive 1D- and 2D-NMR spectroscopy. The absolute configurations of compounds 1–5, 7 …

Effect Of Artificial Sweeteners On The Renin-Angiotensin System In Rats, Jacob Ball

Undergraduate Research Symposium

Normal abundant dietary sugars such as fructose and glucose can contribute to hypertension and other health issues. To avoid these health complications, many individuals use artificial sweeteners. An equivalent intake of some artificial sweeteners also can lead to hypertension. However, Stevia, a sweetener that is isolated from a Paraguayan plant, was shown in relevant literature to decrease blood pressure in both rat specimens and humans. The general purpose of this research project was to study the effect of Stevia and glucose on the expression of two key components of the renin-angiotensin-aldosterone system (RAAS): prorenin receptor (PRR) and angiotensin receptor type …

Rubidium Uptake In Isolated Rat Cardiomyocytes, Jooyoung Lee, Jaekook Sim, Karleen Doering

Undergraduate Research Symposium

The element rubidium is known to have similar biological impact as K+ ions and some studies have shown that heart tissue takes up rubidium through K+ channels and Na+/K+ ATPase pumps. The purpose of the research was to confirm whether or not rubidium was transported into individual cardiomyocytes. Rubidium may be used as a marker to study different physiological functions of K+ and its channels and pumps. The methods used are mainly two parts: isolation of single heart cells and treatment with rubidium. Isolated heart cells were obtained by anesthetizing a rat, extracting the heart, and infusing its aorta with …

Localization And Expression Level Of Vascular Endothelial Growth Factor After Partial Hepatectomy Of Wky Rats, Adam Kronebusch, Tyler Koonst

Undergraduate Research Symposium

Inflammation and fibrosis are indicative of liver regeneration following injury and chronic liver diseases, such as cirrhosis and hepatocellular carcinoma. The formation of new vasculature via the process of angiogenesis is vital to the pathological progression of liver regeneration and these diseases. Thus, inhibiting the process of angiogenesis could have the potential to stop or slow the progression of chronic liver diseases. Vascular endothelial growth factor (VEGF) is the most potent and specific growth factor for initiating the process of angiogenesis, making it a prime target to inhibit angiogenesis. Bevacizumab is an antibody that binds to VEGF, inhibiting it from …

Estrogenic Effects On A Protandrous Hermaphroditic Species: Amphiprion Percula, Randall Burns, Katie Dose

Undergraduate Research Symposium

Estrogen concentrations are increased in aquatic environments due to the addition of pharmaceutical drugs (i.e. birth control) through runoff water. This manipulates maturation of sexes within many species that inhabit aquatic enviornments, including fresh and marine habitats. Amphiprion percula exhibit a hierarchal system behavioral pattern, which determines the social status of individuals within a group. Multiple clown anemonefish, A. percula were studied via a controlled environment and hierarchal succession was observed under estrogenic additions. From this study, data on sex change of a hermaphroditic protandrous species was observed under the influence of three concentrations of natural estrogen. Based on sex …

Trail-R1 Is A Negative Regulator Of Pro-Inflammatory Responses And Modulates Long-Term Sequelae Resulting From Chlamydia Trachomatis Infections In Humans, Mufadhal Al-Kuhlani, James Rothchild, Sukumar Pal, Luis M. De La Maza, Sander Ouberg, Servaas A. Morré, Deborah Dean, David M. Ojcius

All Dugoni School of Dentistry Faculty Articles

The immune system eliminates Chlamydia trachomatis infection through inflammation. However, uncontrolled inflammation can enhance pathology. In mice, TNF-related apoptosis-inducing ligand receptor (TRAIL-R), known for its effects on apoptosis, also regulates inflammation. In humans, the four homologues of TRAIL-R had never been investigated for effects on inflammation. Here, we examined whether TRAIL-R regulates inflammation during chlamydial infection. We examined TRAIL-R1 single nucleotide polymorphisms (SNPs) in an Ecuadorian cohort with and without C. trachomatis infections. There was a highly significant association for the TRAIL+626 homozygous mutant GG for infection vs no infection in this population. To confirm the results observed in the …

Redox Regulation Of Protein Translation In Eukaryotes, Maxim Gerashchenko

Department of Biochemistry: Dissertations, Theses, and Student Research

Gene expression may be controlled at multiple levels, e.g., through genomic architecture, transcription and translation. In the current work, we focused on regulation of protein synthesis. Historically, the investigation of the regulation of gene expression at the level of translation lagged behind the transcriptional control because of the lack of accessible high-throughput methods. Our research has begun with the finding of the use of alternative non-AUG start codon in thioredoxin-glutathione reductase (TGR), a selenoprotein involved in redox control during male reproduction. The use of this codon, CUG, relies on the Kozak consensus sequence and ribosomal scanning mechanism. However, the CUG …

Developing An Unstructured Model To Investigate The Effect Of Ethanol On Product Yields For Glucose And Xylose Cofermentation In Saccharomyces Cerevisiae 424a (Lnh-St), Shane D. Clingenpeel

Open Access Theses

Production of bio-ethanol from lignocellulose requires the efficient fermentation of glucose and xylose, even in the presence of inhibitors. The desired product, ethanol itself, will inhibit the fermentation. A further understanding of how ethanol affects the organism is critical to overcoming its inhibition.

This thesis evaluated the effect of ethanol on the cofermentation of glucose and xylose in two different cases. The first case had an unstructured model created for Saccharomyces cerevisiae 424A (LNH-ST), a genetically modified strain of yeast capable of cofermenting glucose and xylose. The differential equations were based around sugar consumption, and the product yields were investigated …

A Course-Based Research Experience: How Benefits Change With Increased Investment In Instructional Time, Christopher D. Shaffer, Cheryl Bailey, Students And Tas In Genomics Education Partnership Courses

Department of Biochemistry: Faculty Publications

There is widespread agreement that science, technology, engineering, and mathematics programs should provide undergraduates with research experience. Practical issues and limited resources, however, make this a challenge.We have developed a bioinformatics project that provides a coursebased research experience for students at a diverse group of schools and offers the opportunity to tailor this experience to local curriculum and institution-specific student needs. We assessed both attitude and knowledge gains, looking for insights into how students respond given this wide range of curricular and institutional variables. While different approaches all appear to result in learning gains, we find that a significant investment …

Comparison Of Two Separation Methods For Biological Particles: Field-Flow Fractionation (Fff) And Sucrose Density Gradients, Cody E. Garrison

OES Theses and Dissertations

Sucrose gradient centrifugation and Field-flow fractionation (FFF) are two different particle separation methods that overcome the problems of similar size microorganisms clumping together during standard filtration methods. FFF separates particles based on size and density via the parabolic velocity profile of laminar flow in a ribbon-like channel. The sucrose method separates particles via centrifugation in a density gradient. Both techniques worked well in separating eukaryotic from prokaryotic microbes, with the preferred method depending on the type and relative abundance of organisms to be separated. Minicells were separated from mother cells in transformed Escherichia coli cultures, heterotrophic flagellates (e.g., Diplonema papillatum …

Exploration Of Mutations In Erythroid 5-Aminolevulinate Synthase That Lead To Increased Porphyrin Synthesis, Erica Jean Fratz

USF Tampa Graduate Theses and Dissertations

5-Aminolevulinate synthase (ALAS; EC 2.3.1.37) is a pyridoxal 5'-phosphate (PLP)-dependent enzyme that catalyzes the first committed step of heme biosynthesis in animals, the condensation of glycine and succinyl-CoA yielding 5-aminolevuliante (ALA), CoA, and CO2. Murine erythroid-specific ALAS (mALAS2) variants that cause high levels of PPIX accumulation provide a new means of targeted, and potentially enhanced, photosensitization. Transfection of HeLa cells with expression plasmids for mALAS2 variants, specifically for those with mutated mitochondrial presequences and a mutation in the active site loop, caused significant cellular accumulation of PPIX, particularly in the membrane. Light treatment of HeLa cells expressing mALAS2 variants revealed …

Stoichiometries And Affinities Of Interacting Proteins From Concentration Series Of Solution Scattering Data: Decomposition By Least Squares And Quadratic Optimization, Himanshu Chandola, Tim E. Williamson, Bruce A. Craig, Alan M. Friedman, Chris Bailey-Kellogg

Dartmouth Scholarship

In studying interacting proteins, complementary insights are provided by analyzing both the association model (the stoichiometry and affinity constants of the intermediate and final complexes) and the quaternary structure of the resulting complexes. Many current methods for analyzing protein interactions either give a binary answer to the question of association and no information about quaternary structure or at best provide only part of the complete picture. Presented here is a method to extract both types of information from X-ray or neutron scattering data for a series of equilibrium mixtures containing the initial components at different concentrations. The method determines the …

Combined Metal-Enhanced Fluorescence-Surface Acoustic Wave (Mef-Saw) Biosensor, Samuel Morrill

USF Tampa Graduate Theses and Dissertations

Immunofluorescence assays are capable of both detecting the amount of a protein and the location of the protein within a cell or tissue section. Unfortunately, the traditional technique is not capable of detecting concentrations on the nanoscale. Also, the technique suffers from non-specific attachment, which can cause false-positives, as well as photobleaching when detecting lower concentrations is attempted. There is also a time constraint problem since the technique can take from many hours to a few days in some cases.

In this work, metal-enhanced fluorescence (MEF) is used to lower the detection limit and reduce photobleaching. Unfortunately, MEF also increases …

Desorption Electrospray Ionization Mass Spectrometry Imaging: Instrumentation, Optimization And Capabilities, Manan Dhunna

Theses and Dissertations

Desorption Electrospray Ionization Mass spectrometry Imaging (DESI-MSI) is an area of great interest and a promising tool in the field of chemical imaging. It is a powerful, label-free technique, which can determine, map and visualize different molecular compounds on a sample surface. The amount of information acquired in a single DESI-MSI experiment is enormous compared to other techniques, as it can simultaneously detect different compounds with their spatial distribution on the surface. The experiment can be used to produce two-dimensional and three-dimensional images. Chapter 2 focuses on the design and optimization of the setup for performing DESI-MS imaging on various …