Biochemistry, Biophysics, and Structural Biology Commons^™

Isothermal Titration Calorimetry Studies Of Protein-Mediated Interactions And Preliminary Structural Studies Of Tandem Pdz1-2 Domain Of Psd-95 Protein, Ana Jankovic

Wayne State University Dissertations

Protein-mediated interactions that involve multiple ligands in their binding mechanisms are critical for many cellular functions. The primary focus of this dissertation research was to investigate such interactions for two proteins, the PDZ domain and frataxin, involving peptide and metal binding ligands, respectively. The three component projects of this work comprised (1) thermodynamic analysis of PDZ domain binding using calorimetry; (2) X-ray crystallographic structural studies of a PDZ dual domain; and (3) thermodynamic analysis of frataxin binding to iron. The specific goal of the research conducted with the PDZ domains was to understand the mechanism of action of multiple/tandem protein …

Lipid Uptake And Metabolism In The Parasitic Protozoan Giardia Lamblia., Mayte Yichoy

Open Access Theses & Dissertations

Giardia lamblia is a protozoan parasite that causes various intestinal syndromes, and it is a common cause of water-borne illness worldwide, both in developed and developing countries. Giardia attaches to the mucosal epithelia of the duodenum below the bile duct, where it is exposed to bile salts and dietary lipids. G. lamblia is unable to synthesize lipids de novo and must therefore scavenge necessary lipids from its extracellular environment and remodel them as needed. However, the current lipidomic analysis (presented in this Dissertation) has revealed that while the Giardia lipidome is rich in phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylglycerol (PG), …

The Impact Of Environment On Virulence Of The Pathogenic Yeast Cryptococcus Gattii, Deborah Jean Springer

Legacy Theses & Dissertations (2009 - 2024)

Four serotypes of Cryptococcus are responsible for most human and animal infections. C. gattii , serotype B and C, are the primary the causative agent of cryptococcosis in immune competent individuals whilst, C. neoformans var. neoformans serotype D, and C. neoformans var. grubii serotype A are most prevalent in immunocompromised hosts world-wide. C. gattii is recognized as a species distinct from C. neoformans based on differences in clinical manifestations, morphology, biological characteristics, and environmental niche. We used the plant model Arabidopsis thaliana plants and plant derived substrates as a model to explore C. gattii interactions in its ecological niche. C. …

A Locus-Based Paradigm For Generating Systems Biological Inferences From Large Scale Functional Genomics Datasets, Ajish Dominic George

Legacy Theses & Dissertations (2009 - 2024)

Genomics data is growing at a exponential rate. The ability to integrate new results with existing knowledge about genomic biology is rapidly becoming the limiting factor as there no universal language with which to describe genomic functional elements. To integrate and compare new and existing genomic data, we define our basic functional unit of a genome to be a locus -- a set of positional coordinates along any genome with an arbitrary amount of functional annotations attached. The locus concept enables addressing genomic elements and annotations at any level of granularity from entire swaths of chromosomes to single base-positions. We …

Opportunism And Diversity In The Lifestyle Of A Group Ii Intron, Arthur R. Beauregard

Legacy Theses & Dissertations (2009 - 2024)

Group II introns are mobile retroelements. They invade the cognate intron-minus gene in an efficient process known as retrohoming. They can also retrotranspose to ectopic sites at low frequency. Retrohoming occurs by the intron RNA reverse-splicing into double-stranded DNA (dsDNA) through an endonuclease-dependent pathway. However, in retrotransposition in Lactoccocus lactis, the intron inserts predominantly into single-stranded DNA (ssDNA), in an endonuclease-independent manner. Unlike in L. lactis, in Escherichia coli the Ll.LtrB intron retrotransposes frequently into dsDNA, and the process is dependent on the endonuclease activity of the intron-encoded protein. Further, the endonuclease-dependent integrations preferentially occurred around the origin and terminus …

Role Of Cyp2a5 In Drug Metabolism, Chemical Toxicity, And Maintenance Of Steroid Hormone Homeostasis : Insights From Studies On A Novel Cyp2a5-Null Mouse Model, Xin Zhou

Legacy Theses & Dissertations (2009 - 2024)

The central hypothesis is that CYP2A5 plays an important role in the metabolism of xenobiotic substrates, and in the toxicity induced by over-exposure to drugs, as well as in the metabolism of endogenous compounds and regulation of steroid hormone homeostasis. The specific aims are: 1) to generate and characterize a Cyp2a5-null mouse; 2) to determine the role of CYP2A5 in the systemic clearance of nicotine and cotinine; and 3) to explore the mechanisms underlying the resistance of the lateral nasal gland (LNG) of male Cyp2g1-null/Cyp2a5-low mouse and Cyp2a5-null mouse to acetaminophen (AP) toxicity.

An Rnai Screen Targeting The Protein Tyrosine Kinases Identifies Bruton's Tyrosine Kinase (Btk) As A Breast Cancer Cell Survival Factor, Cheryl Lynne Eifert

Legacy Theses & Dissertations (2009 - 2024)

The receptor protein tyrosine kinases (RPTKs) and the non- receptor protein tyrosine kinases (PTKs) are among the most commonly up-regulated genes found in all types of cancers. Although, a large body of data implicates a majority of tyrosine kinases (TKs) in cancer, few have been extensively evaluated for any potential therapeutic benefit in any of the many subtypes of breast cancer. We have used RNA interference (RNAi) to perform a large-scale loss-of-function analysis to facilitate the identification of individual factors necessary for the survival of an ErbB2 positive breast cancer cell line. We have found that 30% of the TKs …

Genetically Engineered Repetitive Polypeptides : Design, Synthesis, Characterization, And Applications, Natalya I. Topilina

Legacy Theses & Dissertations (2009 - 2024)

This work is dedicated to the investigation of protein folding with the emphasis on the aggregation and amyloid fibrils formation. The focus of the research is to elucidate the relationship between polypeptide chain sequence and folding/aggregation properties. For this purpose, i) libraries of the de novo macromolecular repetitive β-sheet forming polypeptides were designed, and ii) the strategy for their rapid creation was developed. The strategy enables retention of a basic polypeptide core, yet allowing variations in the repetitive sequence, degree of polymerization and distribution of specific amino acids. The polypeptides were expressed in E. coli, purified, and characterized by various …

Secondary Structures And Thermodynamic Properties Of Ampa Receptor Aptamers, Sabarinath Jayaseelan

Legacy Theses & Dissertations (2009 - 2024)

Using systematic evolution of ligands by exponential enrichment (SELEX), our lab previously selected a class of competitive RNA aptamers against the alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptors. One aptamer in this class was found to have a minimal, functional sequence of 58 nucleotides. In vitro transcription generates two RNA transcripts with the same sequence, which we named M1 and M2, both of which are required to work together to inhibit the AMPA receptors. Although the M1 and M2 species have the same sequence, they cannot be interconverted through unfolding by denaturation/refolding by renaturation. To probe the secondary structures and the thermodynamic …

The Recognition And Folding Of Ncp7 (Nucleocapsid Protein) With Tardna And Psi Site Rna Hairpin Structures From Hiv-1 : A Spin Label Study, Yan Sun

Legacy Theses & Dissertations (2009 - 2024)

The nucleocapsid (NC) protein NCp7 of the human immunodeficiency virus type 1(HIV 1) is a small basic protein with two zinc finger motifs. NCp7 has key roles in virus replication and structure, which rely on its interactions with nucleic acids. We investigated the interaction of NCp7 with Transactivation Response Element (TAR) DNA which is critical for minus strand transfer during the HIV 1 reverse transcription. The EPR spin probe nitroxide was used as the reporter. Binding of NCp7 to TARDNA caused TARDNA condensation, as inferred from the probe tumbling time which markedly increased to several nanoseconds at a 4:1 NCp7 …

Molecular Evolution Of Genes Underlying Phenotypic Differences Between Humans And Chimpanzees, Santhoshi Bandla

Legacy Theses & Dissertations (2009 - 2024)

Chimpanzees (Pan troglodytes) and bonobos (P. paniscus) are often used as models to study the genetic and morphological changes on the lineage leading to the modern humans (Homo sapiens). Results of this dissertation suggest that, in comparison to other hominoids, chimpanzees and bonobos are more derived in their relative testes sizes and promiscuous mating systems. Phylogenetic analysis of genes that might underlie increased testes size revealed that, in addition to being a sex-determining gene, SRY displays Pan-specific amino acid replacements that make it a compelling candidate as a testes-size determining gene. Strikingly, SRY and another candidate gene, DMRT3, display patterns …

Study Of Dynamic Processes In Protein Synthesis Using Heterogeneous Ribosome Specimens, Jie Fu

Legacy Theses & Dissertations (2009 - 2024)

Single-particle reconstruction from cryo-electron microscopy (cryo-EM) images is a widely used technique in studying the structure of macromolecular complexes. This technique allows the visualization of molecules in their native hydrated state. The heterogeneity of two-dimensional projection images, resulting from the co-existence of different states of a macromolecular complex, remains a major obstacle, as it impairs the validity of reconstruction and limits the progress toward higher resolution. On the other hand, co-existing structures, if successfully extracted from a single dataset, can provide valuable information about the equilibrium and dynamics of the biological system being studied.

Regulation Of Intracellular Calcium Concentration By Nanosecond Pulsed Electric Fields, Shaka S. Scarlett, Jody A. White, Peter F. Blackmore, Karl H. Schoenbach, Juergen Kolb

Bioelectrics Publications

Changes in [Ca²⁺]_i response of individual Jurkat cells to nanosecond pulsed electric fields (nsPEFs) of 60 ns and field strengths of 25, 50, and 100 kV/cm were investigated. The magnitude of the nsPEF-induced rise in [Ca²⁺]_i was dependent on the electric field strength. With 25 and 50 kV/cm, the [Ca²⁺]_i response was due to the release of Ca²⁺ from intracellular stores and occurred in less than 18 ms. With 100 kV/cm, the increase in [Ca²⁺]_i was due to both internal release and to influx across the plasma …

Retrocyclin, A Potent Hiv-1 Entry Inhibitor, Nitya Venkataraman

Electronic Theses and Dissertations

Human immununodeficiency virus (HIV) infection is the leading cause of death due to viral infections worldwide. In the absence of an effective vaccine or consistent male condom use, there is a clear need for female-controlled preventatives such as topical vaginal microbicides. Recent attention has been focused on developing natural antimicrobial peptides, as anti-retroviral microbicides. Increasing evidence suggests that cationic antimicrobial peptides such as defensins are effective HIV-1 inhibitors. Human alpha- and beta-defensins contribute substantially to innate immune defenses against microbial and viral infections. Certain nonhuman primates also produce theta-defensins – 18 residue cyclic peptides that are potent HIV-1 entry inhibitors. …

Mcp-1 And App Involvement Of Glial Differentiation And Migration Of Neuroprogenitor Cells, Emmanuel Vrotsos

Electronic Theses and Dissertations

Neuroprogenitor cells are an important resource because of their potential to replace damaged cells in the brain caused by trauma and disease. It is of great importance to better understand which factors influence the differentiation and migration of these cells. Previously it has been reported that neuroprogenitor cells undergoing apoptotic stress have increased levels of Amyloid precursor protein (APP) and increased APP expression results in glial differentiation. APP activity was also shown to be required for staurosporine induced glial differentiation of neuroprogenitor cells. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine that is expressed during inflammatory. The binding of MCP-1 to …

Asymmetric Transfer Hydrogenation Of Allylic Alcohols With Homogeneous Chiral Ruthenium Catalysts: A Proposed Mechanism, Marie G. Beauchamps

Seton Hall University Dissertations and Theses (ETDs)

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Letter From The Dean, Lalit Verma

Discovery, The Student Journal of Dale Bumpers College of Agricultural, Food and Life Sciences

No abstract provided.

Hmgb1 Mediates Endogenous Tlr2 Activation And Brain Tumor Regression, James Curtin, Naiyou Liu, Marianela Candolfi, Weidong Xiong, Hikmat Assi, Kader Yagiz, Matthew Edwards, Kathrin Michelsen, Kurt Kroeger, Chunyan Liu, Akm Ghulam Muhammad, Mary Clark, Moshe Arditi, Begonya Comin-Anduix, Antoni Ribas, Pedro Lowenstein, Maria Castro

Articles

BACKGROUND: Glioblastoma multiforme (GBM) is the most aggressive primary brain tumor that carries a 5-y survival rate of 5%. Attempts at eliciting a clinically relevant anti-GBM immune response in brain tumor patients have met with limited success, which is due to brain immune privilege, tumor immune evasion, and a paucity of dendritic cells (DCs) within the central nervous system. Herein we uncovered a novel pathway for the activation of an effective anti-GBM immune response mediated by high-mobility-group box 1 (HMGB1), an alarmin protein released from dying tumor cells, which acts as an endogenous ligand for Toll-like receptor 2 (TLR2) signaling …

Pressure-Driven Transport Of Particles Through A Converging-Diverging Microchannel, Ye Ai, Sang W. Joo, Xiangchun Xuan, Shizhi Qian

Mechanical & Aerospace Engineering Faculty Publications

Pressure-driven transport of particles through a symmetric converging-diverging microchannel is studied by solving a coupled nonlinear system, which is composed of the Navier-Stokes and continuity equations using the arbitrary Lagrangian-Eulerian finite-element technique. The predicted particle translation is in good agreement with existing experimental observations. The effects of pressure gradient, particle size, channel geometry, and a particle's initial location on the particle transport are investigated. The pressure gradient has no effect on the ratio of the translational velocity of particles through a converging-diverging channel to that in the upstream straight channel. Particles are generally accelerated in the converging region and then …

The Metal Chelators, Trientine And Citrate, Inhibit The Development Of Cardiac Pathology In The Zucker Diabetic Rat, John W. Baynes, David B. Murray

Faculty Publications

Purpose. The objective of this study was to determine the efficacy of dietary supplementation with the metal chelators, trientine or citric acid, in preventing the development of cardiomyopathy in the Zucker diabetic rat.

Hypothesis. We hypothesized that dietary chelators would attenuate metal-catalyzed oxidative stress and damage in tissues and protect against pathological changes in ventricular structure and function in type II diabetes.

Methods. Animals (10 weeks old) included lean control (LC, fa/+), untreated Zucker diabetic fatty (ZDF, fa/fa), and ZDF rats treated with either trientine (triethylenetetramine) or citrate at 20 mg/d in drinking water, starting …

Vibrational Spectroscopy Of Isotopically Labeled Indoles And Electron Transfer Involving Indole (Tryptophan) Radicals, Senghane Dominique Dieng

Theses, Dissertations and Culminating Projects

Vibrational spectroscopy of tryptophan can be used as a probe for local protein conformation and to study protein electron transfer. For the interpretation of the vibrational spectra, the proper assignment of the vibrational bands to normal modes is essential. We report the experimentally measured infrared and Raman spectra of tryptophan, indole and 3-methylindole as well as of several of their isotope substituted forms; tryptophan indole-d₅ and -¹⁵N₂, and indole 2-¹³C. The effect of the exchange of the indole NH to ND on the vibrational spectra of these molecules was also determined. The measurements …

Hydroxyl Radical Is Produced Via The Fenton Reaction In Submitochondrial Particles Under Oxidative Stress: Implications For Diseases Associated With Iron Accumulation, Carin Thomas, Melissa M. Mackey, Amy A. Diaz, David P. Cox

All Faculty Scholarship for the College of the Sciences

Mitochondrial dysfunction and reactive oxygen species (ROS) are often implicated in diseases involving oxidative stress and elevated iron. As mitochondria produce ATP by oxidative phosphorylation, ROS by-products are generated from the electron transport chain. Although superoxide and hydrogen peroxide have been thoroughly investigated, little evidence documents hydroxyl radical (HO•) production in mitochondria. In order to determine whether HO• is generated under oxidative stress conditions by a Fenton-type mechanism, bovine heart submitochondrial particles were examined for HO• in the presence and absence of iron ligands, antioxidant enzymes and HO• scavengers. HO• was measured as 2,3- and 2,5-dihydroxybenzoic acid (DHBA), using HPLC …

Cadmium-Mediated Rescue From Er-Associated Degradation Induces Expression Of Its Exporter, David J. Adle, Wenzhong Wel, Nathan Smith, Joshua J. Bles, Jaekwon Lee

Department of Biochemistry: Faculty Publications

Cadmium is a highly toxic environmental contaminant that has been implicated in various disorders. A major mechanism for cadmium detoxification in the yeast Saccharomyces cerevisiae relies on extrusion via Pca1, a P-type ATPase. While an N-terminal degron targets Pca1 for degradation before its secretion to the plasma membrane, cadmium in the growth media rapidly upregulates Pca1 by preventing its turnover. Here we show that the endoplasmic reticulum-associated degradation (ERAD) system, known for its role in quality control of secretory proteins, is unexpectedly responsible for the regulation of Pca1 expression by cadmium. Direct cadmium sensing at the ER by a degron …

Crystal Structure Of Acivicin-Inhibited Γ-Glutamyltranspeptidase Reveals Critical Roles For Its C-Terminus In Autoprocessing And Catalysis, Kristin Williams, Sierra Cullati, Aaron Sand, Ekaterina I. Biterova, Joseph J. Barycki

Department of Biochemistry: Faculty Publications

Helicobacter pylori γ-glutamyltranspeptidase (HpGT) is a general γ-glutamyl hydrolase and a

demonstrated virulence factor. The enzyme confers a growth advantage to the bacterium, providing essential amino acid precursors by initiating the degradation of extracellular glutathione and glutamine. HpGT is a member of the N-terminal nucleophile (Ntn) hydrolase superfamily and undergoes autoprocessing to generate the active form of the enzyme. Acivicin is a widely used γ-glutamyltranspeptidase inhibitor that covalently modifies the enzyme, but its precise mechanism of action remains unclear. The time-dependent inactivation of HpGT exhibits a hyperbolic dependence on acivicin concentration with kmax = 0.033 ± 0.006 sec^{−1 …}

Generation Of A Reporter Library Of Eralpha Interacting Dna Sequences, Cormac Jennings

Masters

Oestrogens are a group of steroid hormones of which oestradiol is the major form. Oestrogens are present in men and women and some of their main physiological roles involve female and male reproduction, bone metabolism and homeostasis. Oestrogens carry out their actions by diffusing across the cell membrane and binding to their receptor called the oestrogen receptor (ER), of which two types exist, ERα and ERβ. ERs regulate gene expression through the binding of DNA, most notably the estrogen response element (ERE). Breast cancer is the most common malignancy in women in industrialised countries and 65 percent of breast cancers …

Probing The Urea Dependence Of Residual Structure In Denatured Human Α-Lactalbumin, Victoria A. Higman, Heike I. Rösner, Raffaella Ugolini, Lesley H. Greene, Christina Redfield, Lorna J. Smith

Chemistry & Biochemistry Faculty Publications

Backbone ¹⁵N relaxation parameters and ¹⁵N–¹H^N residual dipolar couplings (RDCs) have been measured for a variant of human α-lactalbumin (α-LA) in 4, 6, 8 and 10 M urea. In the α-LA variant, the eight cysteine residues in the protein have been replaced by alanines (all-Ala α-LA). This protein is a partially folded molten globule at pH 2 and has been shown previously to unfold in a stepwise non-cooperative manner on the addition of urea. ¹⁵N R₂ values in some regions of all-Ala α-LA show significant exchange broadening which is reduced as the urea …

Comparative Efficacy Of Bioud To Other Commercially Available Arthropod Repellants Against The Ticks Amblyomma Americanum And Dermacentor Variabilis On Cotton Cloth, Brooke W. Bissinger, Jiwei Zhu, Charles S. Apperson, Daniel E. Sonenshine, D. Wesley Watson, R. Michael Roe

Biological Sciences Faculty Publications

BioUD is an arthropod repellent that contains the active ingredient 2-undecanone originally derived from wild tomato plants. Repellency of BioUD was compared with five commercially available arthropod repellents against the ticks Amblyomma americanum (L.) and Dermacentor variabilis Say in two-choice bioassays on treated versus untreated cotton cheesecloth. Overall mean percentage repellency against both species was greatest for and did not differ significantly between BioUD (7.75% 2-undecanone) and products containing 98.1% DEET, 19.6% IR3535, and 30% oil of lemon eucalyptus. Products containing 5% and 15% Picaridin and 0.5% permethrin were also repellent compared with untreated controls but to a lesser degree …

Substrate And Regulation Of Mitochondrial Μ-Calpain, Aashish Joshi

University of Kentucky Doctoral Dissertations

μ -Calpain is localized to the mitochondrial intermembrane space. Apoptosisinducing factor (AIF), which executes caspase-independent cell death, is also localized to the mitochondrial intermembrane space. Following processing at the N-terminus, AIF becomes truncated (tAIF) and is released from mitochondria. The protease responsible for AIF processing has not been established. The same submitochondrial localization of mitochondrial μ-calpain and AIF gives support to the hypothesis that mitochondrial μ-calpain may be responsible for processing AIF. Atractyloside-induced tAIF release in rat liver mitochondria was inhibited by cysteine protease inhibitor MDL28170, but not by calpain inhibitors PD150606 or calpastatin. Moreover, μ-calpain immunoreactivity was difficult to …

Due-B, A New Human Dna Replication Protein, Is The Functional Homolog Of S. Cerevisiae Sld3, Jianhong Yao

Browse all Theses and Dissertations

DNA unwinding elements (DUEs) are commonly found at DNA replication origins. The DUE binding protein (DUE-B) is crucial for the initiation of DNA replication in eukaryotes. The unique 59 amino acid C-terminal part of DUE-B shares nearly 50% similarity with yeast the C-terminus of Sld3. DUE-B plays a key role in eukaryotic DNA replication because it is required for the loading of Cdc45, the MCM helicase activator, on chromatin. Here we show that DUE-B, just like yeast Sld3, binds to Cdc45 and TopBP1 through its C-terminus in Sf9 cells and in vitro. We also show that DUE-B, Cdc45 and TopBP1 …

Dose-Dependent Effects Of Oxygen On Metabolism In Rat Cortico-Hippocampal Brain Tissue Slices, Jennifer Lynne Hollyfield

Browse all Theses and Dissertations

Studies have shown that 95% oxygen increases neuronal excitability and ROS production. We wanted to investigate the dose-dependent effects of oxygen on brain slice metabolism. We exposed rat brain cortico-hippocampal tissue slices to 0.40, 0.95, and 4.50 ATA O2 for 60 minutes, made dual-phase tissue extracts, and used multi-nuclear NMR experiments to elucidate the slice metabolism. We found that low doses of oxygen may shift metabolism toward anaerobic glycolysis. Elevated lactate suggests this shift, along with elevated ratios of NAD+/NADH which may drive the reactions toward the production of lactate. The results also suggest that high doses of oxygen may …