Biochemistry, Biophysics, and Structural Biology Commons^™

Biochemical And Cellular Studies Of Apobec3 Family Dna-Cytosine Deaminases, Sachini Umedi Siriwardena

Wayne State University Dissertations

The AID/APOBEC family of enzymes deaminate cytosines in single-stranded DNA to uracils leading to base substitutions and strand breaks. Members of APOBEC3 family in humans are induced by cytokines produced during the body's inflammatory response to infections and provide innate immunity against viruses. However, there is emerging consensus that these enzymes can cause mutations in the cellular genome depending on the physiological state of the cell and the phase of the cell cycle they are expressed. Since aberrant expression of APOBEC3B was recently identified as a possible source of cancer, we initiated a study to determine the maximally active catalytic …

Alternative Strategies To Inhibit Lysine Methyltransferases And Deubiquitinases In Human Cancers, Nicholas Spellmon

Wayne State University Dissertations

X-ray crystallography is the gold standard method for imagining macromolecules to atomic resolution. Three dimensional data is central to understanding the molecular mechanism how DNA, RNA and proteins function in biological events. Structural insights into these events provide a molecular window to visualize how biological molecules influence human health. Visualizing the architecture of these molecules set the stage for rational and selective drug design. The following dissertation utilizes biochemical and biophysical tools, including X-ray crystallography, to shed light on poorly understood mechanisms related to SMYD2 activity and regulation, USP10 architecture and function, and PDZ-RhoGEF dimerization. SMYD2 is one member of …

Validating Functional Mechanisms For Non-Coding Genetic Variants Associated With Complex Traits, Cynthia Ann Kalita

Wayne State University Dissertations

Genome-wide association studies (GWAS) have identified a large number of genetic variants associated with disease as well as normal phenotypic variation for complex traits. However challenges remain in determining the functional relevance of human DNA sequence variants. Even after fine mapping, most variants are located in non-coding regions making it difficult to infer mechanisms linking individual genetic variants with the disease trait. In addition, we do not know under which environmental conditions the sequence variants have a functional impact, and whether they become one of many factors involved in complex phenotypes at the organismal level.

Chapter 1 describes computational methods …

Polarized Localization Microscopy (Plm) Detects Nanoscale Membrane Curvature And Induced Budding By Cholera Toxin Subunit B (Ctxb), Abir Kabbani

Wayne State University Dissertations

The curvature of biological membranes at the nanometer scale is critically important for vesicle trafficking, organelle morphology, and disease propagation. Many proteins and lipids interact with diverse curvature sensing and curvature generating mechanisms. Deciphering the molecular mechanisms of toxin-membrane interactions has been limited by the resolution and drawbacks of conventional experimental techniques. This study reveals the inherent membrane bending capability of cholera toxin subunit B (CTxB) through the development and implementation of Polarized Localization Microscopy (PLM). PLM is a pointillist optical imaging technique for the detection of nanoscale membrane curvature in correlation with single-molecule dynamics and molecular sorting.

PLM combines …

Investigation Of The Saccharomyces Cerevisiae Gpi Transamidase: Insights Into Its Activity And Subunit-Subunit Interactions, Travis Ness

Wayne State University Dissertations

Glycosylphosphatidylinositol (GPI) anchoring of proteins is a eukaryotic, posttranslational

modification catalyzed by GPI transamidase (GPI-T). The Saccharomyces

cerevisiae GPI-T is composed of five membrane-bound subunits: Gaa1, Gpi8, Gpi16,

Gpi17, and Gab1. Structural and functional studies have been hindered by the

complexity of this enzyme. Conditions to purify the Gpi8:Gaa1:Gpi16 GPI-T heterotrimer

from yeast have been reported, but an understanding of the subunit functions,

interactions, and stoichiometry remain unclear. Furthermore, a reliable, quantitative, in

vitro assay for this important post-translational modification has remained elusive for

nearly three decades.

Our laboratory has developed an in vitro peptide cleavage assay that correlates

changes …

Carbohydrate-Based Inducers Of Cellular Stress For Targeting Cancer Cell Metabolism, Fidelis Ndombera

Wayne State University Dissertations

ABSTRACT

CARBOHYDRATE-BASED INDUCERS OF CELLULAR STRESS FOR TARGETING CANCER CELL METABOLISM

by

FIDELIS TOLOYI NDOMBERA

May 2018

Advisor: Dr. Young-Hoon Ahn

Major: Chemistry (Biochemistry)

Degree: Doctor of Philosophy

Metabolic reprogramming and redox control of cancer cells is vital for their proliferation, but also provides selective strategies for treating cancer. Increased generation of reactive oxygen species (ROS) and an intricate control of redox status in cancer cells relative to normal cells provide a basis for designing ROS-inducing anticancer agents. In my work, I designed, synthesized and evaluated carbohydrate-based small molecules for ROS-generation, cytotoxicity and redox signaling and stress response. Our data …

Chchd10, A Novel Bi-Organellar Regulator Of Cellular Metabolism: Implications In Neurodegeneration, Neeraja Purandare

Wayne State University Dissertations

CHCHD10 (Coiled-coil Helix Coiled-coil Helix Domain containing protein 10) and MNRR1 (Mitochondrial Nuclear Retrograde Regulator 1, also known as CHCHD2), have been shown by us to be stress regulators of mitochondrial function that act both in the mitochondria and in the nucleus. Both are members of the twin CX9C family, but CHCHD10 in particular, has been found in mutant form to be linked to a myriad of neurodegenerative conditions. In mitochondria, both activate cytochrome c oxidase (COX) whereas in the nucleus, both act as transcription regulators of a subset of genes that contain a 13-bp sequence termed as the oxygen …

Role Of Sirna Pathway In Epigenetic Modifications Of The Drosophila Melanogaster X Chromosome, Nikita Deshpande

Wayne State University Dissertations

Eukaryotic genomes are organized into large domains of coordinated regulation. The role of small RNAs in formation of these domains is largely unexplored. An extraordinary example of domain-wide regulation is X chromosome compensation in Drosophila melanogaster males. This process occurs by hypertranscription of genes on the single male X chromosome. Extensive research in this field has shown that the Male Specific Lethal (MSL) complex binds X-linked genes and modifies chromatin to increase expression. The components of this complex, and their actions on chromatin, are well studied. In contrast, the mechanism that results in exclusive recruitment to the X chromosome is …

Design, Synthesis, And Reactivity Of Homo- And Heterobimetallic Complexes Bridged By A Xanthene Linker, Thilini Samangi Hollingsworth

Wayne State University Dissertations

Cooperative reactivity of bimettalics can be is observed in many different areas of chemistry and have been increasingly investigated because of the advantageous reactivity when compared to the corresponding mononuclear systems. The focus of my dissertation is on (1) investigation of the homobimetallic cooperativity in lactide polymerization catalysis; (2) investigation of the heterobimetallic cooperativity in the biomimetic studies of Mo-Cu carbon monoxide dehydrogenase (CODH) enzyme in order to make a functional model of its active site.

Three new main group bis(alkoxide) complexes Mg(OR)2(THF)2, Zn(Cl)(μ2-OR)2Li(THF) and In(OR)2(μ2-Cl)2Li(THF)2 featuring bulky alkoxide [OCtBu2Ph] were synthesized serve as metal alkoxide precursors for bimetallic lactide …

Methionine Sulfoximine: A Novel Anti Inflammatory Agent, Tyler Peters

Wayne State University Dissertations

ABSTRACT

METHIONINE SULFOXIMINE: A NOVEL ANTI-INFLAMMATORY AGENT

by

TYLER J. PETERS

October 2018

Advisor: William Brusilow

Major: Biochemistry and Molecular Biology

Degree: Doctor of Philosophy

The glutamine synthetase inhibitor methionine sulfoximine (MSO), shown previously to prevent death caused by an inflammatory liver response in mice, was tested on in vitro production of cytokines by mouse peritoneal macrophages triggered with lipopolysaccharide (LPS). MSO significantly reduced the production of Interleukin 6 (IL-6) and Tumor Necrosis Factor Alpha (TNFα) at 4 and 6 hours after LPS-treatment. This reduction did not result from decreased transcription of IL-6 and TNFα genes, and therefore appeared to …

Effect Of Endoplasmic Reticulum Stress On Vascular Smooth Muscle Cells And Its Regulation Of Sm22Α, Neeraja Priyanka Annam

Wayne State University Dissertations

Background: The vascular smooth muscle cells(VSMC) possess the ability to differentiate into a synthetic phenotype in response to stress. This phenotypic modulation may be accompanied by inflammatory or osteogenic response in chronic stress. The synthetic state is characterized by low levels of contractile markers unlike the differentiated state.

Hypothesis: Endoplasmic reticulum (ER) stress causes phenotypic modulation in VSMCs leading to apoptosis. Many transcription factors induced by ER stress contribute to the downregulation of Sm22α. Perturbation in cytoskeletal dynamics exacerbates the ER stress response.

Methods: Ex-vivo culture was used to establish importance of Sm22 in ER stress. In vitro analysis was …

The Development Of Chemical Methods To Discover Kinase Substrates And Map Cell Signaling With Gamma-Modified Atp Analog-Dependent Kinase-Catalyzed Phosphorylation, Dissanayaka Mudiyanselage Maheeka Madhubashini Embogama

Wayne State University Dissertations

Kinase-catalyzed phosphorylation plays an important role in cell physiology by regulating a myriad of cellular functions. Thus aberrant kinase activity is implicated in various diseases. Methods are needed to discover kinase substrates and map signaling pathways to explore biology and to help drug discovery. A few techniques are currently available to discover kinase substrate and map cell signaling. However, to augment kinase substrate discovery approaches, it is essential to develop alternative techniques. Pflum has recently discovered cosubstrate promiscuity of protein kinases with gamma-modified ATP analogs. Here, kinase-catalyzed biotinylation with ATP-biotin was used to develop novel tools to discover kinase substrates …

P120 Catenin Regulates Inflammation In Macrophage, Xiaoqing Guan

Wayne State University Dissertations

Objective: p120 catenin (p120ctn) has been reported to play a critical role in maintenance of the stability of adherens junctions. It also has potential anti-inflammatory effects in epithelial and endothelial cells. This research was designed to evaluate the effects of p120ctn on inflammatory responses in human macrophages upon LPS stimulation, as well as the possible mechanism by which p120ctn regulates LPS-induced proinflammatory response in macrophages. Methods: THP-1 cells were induced to differentiate into macrophages by PMA. The isoforms of p120ctn were identified via RT-PCR and Western blot. The expression of p120ctn was examined by Western blot in THP-1 derived macrophages …

Understanding The Mechanism Of Oxidative Stress Generation By Oxidized Dopamine Metabolites: Implications In Parkinson's Disease, Nihar Mehta

Wayne State University Dissertations

Oxidation of dopamine to toxic metabolites is considered to be one of the prime factors involved in the death of dopaminergic neurons in Parkinson’s disease. Some dopamine oxidation products have the capability to redox cycle in the presence of molecular oxygen, further contributing to oxidative stress. Therefore, our aim here was to study the redox cycling of dopamine oxidized metabolites and elucidate the underlying mechanism by which they cause oxidative stress.

Redox reactions involve transfer of one or more electrons between two compounds

resulting in either oxidation or reduction. In redox cycling, a compound undergoes

alternate oxidation and reduction, transferring …

Functional Analysis Of Sin3 Isoforms In Drosophila, Nirmalya Saha

Wayne State University Dissertations

he multisubunit SIN3 complex is a global transcriptional regulator. In Drosophila, a single Sin3A gene encodes different isoforms of SIN3, of which SIN3 187 and SIN3 220 are the major isoforms. Previous studies have demonstrated functional non-redundancy of SIN3 isoforms. The role of SIN3 isoforms in regulating distinct biological processes, however, is not well characterized. In addition, how the components of the SIN3 complex modulate the gene regulatory activity of the complex is not well understood. In this study, I identified the biological processes regulated by the SIN3 isoforms. Additionally, I explored how Caf1-55 impacts the gene regulatory activity of …

Structural Basis Of Membrane Protein Scaffolding And Signaling In Human Disease, Joshua Holcomb

Wayne State University Dissertations

Protein structural elucidation by means of X-ray crystallography is a powerful approach for both insight into a proteins biophysical properties and function. To date X-ray crystallography remains the gold standard in high resolution structural determination and serves as the basis for rational drug design for the purpose of combating a number of human diseases. Such an approach also allows for the exploitation of how various proteins interact with their substrates providing a molecular basis for their physiological function. In this dissertation, using X-ray crystallographic analysis along with other biophysical characterization methods, we seek to understand the mechanistic foundation for which …

Role Of Alström Syndrome 1 (Alms1) In Nkcc2 Endocytosis, Thick Ascending Limb Function, Blood Pressure Regulation And Metabolic Function, Ankita Bachhawat Jaykumar

Wayne State University Dissertations

NaCl absorption by the Thick Ascending Limb (TAL) is mediated by the apical Na+/K+/2Cl- co-transporter, NKCC2. Increased NKCC2 activity and apical trafficking are associated to salt sensitive hypertension in rodents and humans. NKCC2 endocytosis is important for maintaining surface NKCC2 such that blocking NKCC2 endocytosis increased NKCC2 surface abundance and NKCC2-mediated NaCl reabsorption. Despite its importance, NKCC2 endocytosis has been poorly studied and a part of the reason may be attributed to the lack of availability of methods with good time resolution. Hence, we developed a method to image apical NKCC2 to monitor its endocytosis in real-time by Total Internal …

Design, Synthesis And Biological Evaluation Of Histone Deacetylase (Hdac) Inhibitors: Saha (Vorinostat) Analogs And Biaryl Indolyl Benzamide Inhibitors Display Isoform Selectivity, Ahmed Negmeldin

Wayne State University Dissertations

HDAC proteins have emerged as interesting targets for anti-cancer drugs due to their involvement in cancers, as well as several other diseases. Several HDAC inhibitors have been approved by the FDA as anti-cancer drugs, including SAHA (suberoylanilide hydroxamic acid, Vorinostat). Unfortunately, SAHA inhibits most HDAC isoforms, which limit its use as a pharmacological tool and may lead to side effects in the clinic. In this work we were interested in developing isoform selective HDAC inhibitors, which may decrease or eliminate the side effects associated with non-selective inhibitors treatment. In addition, isoform selective HDAC inhibitors can be used as biological tools …

Development Of Chemical Tools To Investigate Protein S-Glutathionylation In Response To Metabolic Alteration, Kusal Theekshana Gayan Samarasinghe

Wayne State University Dissertations

Oxidative stress is a common characteristic of age-related diseases such as vascular diseases, diabetes and cancer. Many diseases are known to be regulated by glutathionylation. Glutathionylation is referred to as the formation of disulfide bond between a protein cysteine and a glutathione. To understand the molecular mechanisms behind the disease initiation and progression, identification of such glutathionylated proteins is important. Even though existing methods have been widely used, several limitations of these methods hinder the identification of such proteins in disease conditions. Therefore, we developed a versatile chemical method that generates clickable glutathione inside the cells. In this method, we …

Analysis Of The Secondary Neurodegenerative Consequences Of Primary Oligodendrocyte Stress Through The Use Of The Novel Obiden Mouse Model, Daniel Zdzislaw Radecki

Wayne State University Dissertations

The work of this project was to develop, test and characterize a potential novel mouse model of the neurodegenerative disease Multiple Sclerosis (MS). Historically, MS has been identified as a primary autoimmune disease of the central nervous system (CNS). However, treatments based on this view have met with limited success, and in most cases, fail to prevent progression of MS from mild to moderate and severe forms. Original observations regarding axonal and neuronal pathology in the white and gray matter of the CNS were rediscovered in the 1990s. These observations indicated that even in the absence of the immune system, …

Identification Of Oxygen Optima For Mouse Trophoblast Stem Cells And Human Embryos And The Stress Responses Upon Departing Optima, Yu Yang

Wayne State University Dissertations

Low level of oxygen (O2) occurs physiologically during in vivo embryo development. As developing embryos moving from fallopian tube to uterus, oxygen level gradually decreases to ≤ 5% at the time of blastocyst implantation. Blastocysts are made of two major cell populations, trophoblast cells and inner cell mass, from which trophoblast stem cells (TSCs) and embryonic stem cells (ESCs) are derived respectively. TSCs serve as placental stem cells that later on proliferate and differentiate into placenta. Previous study has shown that 2% O2 is the optimal O2 level for mTSC in vitro growth and potency maintenance, which agrees with their …

Navigating Human Cytomegalovirus (Hcmv) Envelopment And Egress, William Longeway Close

Wayne State University Dissertations

Human cytomegalovirus (HCMV) is a ubiquitous viral pathogen. In individuals with fully functioning and mature immune systems, HCMV is associated with mild symptoms prior to establishing latency. In individuals with naïve or compromised immune systems, HCMV is capable of causing severe organ damage. HCMV is the leading infectious cause of congenital birth defects and a major non-genetic cause of hearing loss. Unfortunately, antiviral treatment options lack diversity due to limited knowledge of virion replication. If HCMV replication were better understood, new antiviral treatments could be developed.

In this work, we describe the development and implementation of new tools to study …

Biochemical, Structural, And Drug Design Studies Of Norovirus And Zika Virus Proteases, Ben Kuiper

Wayne State University Dissertations

Noroviruses, which are the leading cause of acute gastroenteritis, cause an estimated 677 million infections and 213,000 deaths each year worldwide. Noroviruses are classified into seven genogroups (GI-GVII); GI, GII, and GIV have been shown to be infectious in humans. However, GII noroviruses cause the majority of outbreaks (89%). No pharmacologic treatment or vaccine currently exists to treat or prevent norovirus infections.

Recently, the development of a norovirus replicon system, a murine model of norovirus infection, and the development of a biochemical protease assay have allowed for the design and development of norovirus inhibitors. However, the replicon and biochemical assay …

Studies Of Sumoylation In Regulating Mif Stability And Rangap1 Nucleo-Cytoplasmic Shuttling In Controlling Its Sumo Modification, Progga Sen

Wayne State University Dissertations

SUMOylation is an essential post-translational modification that regulates a variety of critical cellular pathways ranging from nuclear transport to protein stability. Accumulating lines of evidence have shown that a perturbation of the SUMOylation pathway is associated with human diseases, especially various types of cancer. Our recent proteomic studies revealed a drastic increase in levels of SUMO2/3 modification on the proinflammatory cytokine MIF in the metastatic breast cancer cell line compared to the non-metastatic control cell line. Interestingly, the increase in levels of both MIF and global SUMO-2/3 modification in the metastatic cells are positively correlated to that of unmodified MIF …

Ligand Binding Studies Of A Peptide Targeting Helix 69 Of 23s Rrna In Bacterial Ribosomes, Hyosuk Seo

Wayne State University Dissertations

In the development of finding a peptide targeting H69 of 23S rRNA in bacterial ribosomes, phage display was employed at pH 5.5, a buffer condition previously reported of H69 preferring a closed conformation. After sequencing, several peptides were chosen through sequence alignment, followed by preparation using solid-phase peptide synthesis. The peptides were characterized using MALDI-TOF and purified with HPLC. A truncated peptide TARHIY was selected from FID assay. Through binding studies using ESI-MS, SPR, BLItz, and NMR, the binding properties of the peptide to H69 were determined, such as binding affinity, stoichiometry, and interaction site. The peptide exhibited moderate binding …

Clinicopathology And Molecular Determinants Underlying Benign Breast And Breast Cancer Lesions, Andreana Holowatyj Holowatyj

Wayne State University Dissertations

Despite converging incidence rates for breast cancers by race, disparities in mortality persist where black women suffer from poorer prognosis compared to white counterparts. To understand the clinical, demographic, and molecular characteristics underlying these disparities, we examined differences among patients with breast cancer to understand the role of human epidermal growth factor receptor 2 (HER2) status, age, and race/ethnicity among women diagnosed with hormone receptor-positive breast cancer, and disparities in surgical therapy among female patients with early stage young-onset breast cancer. Benign breast disease, another known risk factor for breast cancer, includes a histological spectrum of lesions, could contribute to …

Development Of Tools For Phosphosite-Specific Kinase Identification And Discovery Of Phosphatase Substrates, Pavithra Maheshani Dedigama Arachchige

Wayne State University Dissertations

Phosphorylation is a ubiquitous post translational modification implicated in many diseases, such as cancer. The phosphorylation status of cellular proteins is regulated by the activity of kinases and phosphatases. The biological significance of many phosphorylation events remain unknown because the methods to determine which kinase or phosphatase is responsible for phosphorylation are limited. Previously, we established kinase-catalyzed labeling where kinases accept γ-modified ATP analogs, such as ATP-arylazide and ATP-biotin, to label phosphoproteins. To study substrates of kinases and phosphatases, here we developed two new methods using kinase-catalyzed labeling. As one application, we developed K-CLASP (Kinase-catalyzed CrossLinking And Streptavdin Purification) to …

Exploring The Physics Of Proteins At Molecular Level By Neutron And X-Ray Scattering, Utsab Raj Shrestha

Wayne State University Dissertations

The protein structures revealed by the crystallographic studies have provided the valuable information over the years regarding their biological functions. However, such snapshots of protein fluctuations averaged over time may not be enough to fully capture the underlying biological phenomena. A deeper understanding of the protein dynamics is crucial for elucidating the structural pathways or the transition mechanism from the initial state to the final state necessary for regulating the physical and chemical processes. Hence, the biological activities and functions are mainly governed by the protein conformational dynamics. However, the direct correlation of a wide range of protein dynamics to …

Real-Time Investigation Of Bulky Lesion Bypass By Y-Family Dna Polymerase, Dpo4, Using Single Molecule Fret, Pramodha Liyanage

Wayne State University Dissertations

DNA is constantly exposed to various DNA damaging agents that are generated by various internal and external sources. Some of this damage may not be able to be repaired by cellular machineries causing DNA replication to be blocked. Once the replication fork is blocked by a DNA adduct, damage tolerance DNA polymerases, mainly Y-family, are able to restore the DNA replication by synthesizing past the DNA adduct. Benzo[a]pyrene (B[a]P) is one of the most studied environmental carcinogens. It is known to make covalent DNA adducts after metabolic activation and the bulkiness of the B[a]P adducts impose a strong barrier to …

Development Of A Novel Class Of Chemicals For Labeling Abasic Sites In Cellular Dna And Killing Cancer Cells, Shanqiao Wei

Wayne State University Dissertations

Abasic (AP) sites are the most common type of lesions in DNA. Numerous endogenous and exogenous agents and cellular processes can induce the formation of AP sites in DNA. If left unrepaired, the deleterious AP sites cause mutagenesis and cytotoxicity. Methoxyamine is known to react with AP sites and block base excision repair. Another alkoxyamine, aldehyde-reactive probe (ARP) tags AP sites with a biotin and has been widely used to quantify these sites. In this study, I have combined both these abilities into one alkoxyamine, AA3, which reacts toward AP sites with better reactivity than ARP at physiological pH. Additionally, …