Biochemistry, Biophysics, and Structural Biology Commons^™

Functional Characterization Of Accessory Proteins And Novel Activities In Direct And Indirect Trna Aminoacylation, Udumbara Menike Rathnayake

Wayne State University Dissertations

Indirect tRNA aminoacylation is essential for most bacteria and archaea, particularly when these species do not have genes encoding asparaginyl- and/or glutaminyl-tRNA synthetase (AsnRS and GlnRS). In the absence of AsnRS, the first step in Asn-tRNAAsn synthesis involves misacylation of tRNAAsn with aspartate to produce Asp-tRNAAsn; this reaction is catalyzed by a non-discriminating aspartyl-tRNA synthetase (ND-AspRS). Subsequently, in bacteria, an amidotransferase called GatCAB converts Asp-tRNAAsn to Asn-tRNAAsn. An analogous, two-step processes exist to produce Gln-tRNAGln. In this case, a non-discriminating glutamyl-tRNA synthetase (ND-GluRS) misacylates tRNAGln to produce Glu-tRNAGln, which is then converted to Gln-tRNAGln by GatCAB. The central hub of …

Defining The Effect Of Environmental Perturbation On The Male Germline, Molly Estill

Wayne State University Dissertations

Periconceptional environment, according to the Developmental Origins of Health and Disease (DOHaD) theory, influences offspring phenotype, primarily via epigenetic mechanisms. Although the paternal component in humans is poorly understood, both maternal and paternal peri-conceptional environment are now believed to contribute to this phenomenon. Manipulation of the early embryo for treating human infertility, is suspected of contributing to offspring abnormalities through epigenetic mechanisms. To directly address the effects of common assisted reproductive technology procedures on the offspring epigenome, the DNA methylation profiles of newborns conceived naturally, or through the use of intrauterine insemination (IUI), or in vitro fertilization (IVF) using Fresh …

Biochemical, Structural, And Drug Design Studies Of Aspartate Transcarbamoylase From Pseudomonas Aeruginosa And Staphylococcus Aureus, Chandni Patel

Wayne State University Dissertations

Sepsis affects 1.7 million people in the United States every year and nearly 270,000 people die as a result. Sepsis is characterized by systemic inflammation from an infection leading to organ dysfunction and death. Multi-drug resistance in bacteria is increasing globally, and Pseudomonas aeruginosa and Staphylococcus aureus are notorious for their multi-drug resistance and pose a serious need for the development of new antibiotics. The levels of pyrimidines in blood are too low to sustain the growth of bacteria, so they must rely on pyrimidine biosynthesis. Previous studies have shown that a defect in several pyrimidine biosynthetic enzymes resulted in …

The Balance Between Prostaglandin E2 Ep3 And Ep4 Receptors Determines Severity Of Cardiac Damage In Myocardial Infarction And An Angiotensin Ii-Induced Model Of Hypertension, Timothy Dean Bryson

Wayne State University Dissertations

According to the center for disease control about 610,000 people die every year in the United States from heart disease, of which, coronary heart disease is the most common form. One major risk factor for heart attack is hypertension, which affects nearly half of all Americans [472, 473]. PGE2 plays an important role in regulating cardiovascular function and mediating inflammation, both of which contribute to the development of hypertension and/or heart disease. Prostaglandin E2 can act as a vasodilator or vasoconstrictor depending on which of its receptor subtypes are activated.

In general, activation of the EP1 and EP3 receptors is …

Novel Insights Into The Use Of Ercc1 As A Biomarker For Response To Platinum-Based Chemotherapy In Lung Cancer, Joshua Ryan Heyza

Wayne State University Dissertations

ERCC1/XPF is a DNA endonuclease with variable expression in primary tumor specimens, and has been investigated as a predictive biomarker for efficacy of platinum-based chemotherapy in non-small cell lung cancers where up to 30-60% of tumors harbor low to undetectable ERCC1 expression. The failure of an international, randomized Phase III clinical trial utilizing ERCC1 expression to predict response to platinum-based chemotherapy suggests additional mechanisms underlying the basic biology of ERCC1 in the response to platinum-DNA damage remain unknown. In this work, we aimed to characterize a panel of ERCC1 knockout cell lines generated via CRISPR-Cas9 where we identified a synthetic …

Perturbation Of Energy Metabolism At The Center Of The Mechanism Of Action Of Valproate, Michael Ghassan Salsaa

Wayne State University Dissertations

Bipolar disorder (BD) is a common and debilitating psychiatric disorder. Valproic acid (VPA) is one of the major drugs used to treat BD patients. However, it is not universally effective and, in addition, causes severe side effects. Its mechanism of action is not known, which complicates efforts to develop more effective drugs. Studies have established that VPA perturbs metabolism, which is implicated in both the therapeutic mechanism of action of the drug as well as drug toxicity. However, the mechanism whereby VPA causes these perturbations is not understood. To address this knowledge gap, I investigated the acute and chronic effects …

The Dynamic Nature And Biophysical Characterization Of Isu1, Fe-S Cluster Assembly Scaffold Protein In Saccharomyces Cerevisiae, And Its Significance To Human Disease, Brianne Elizabeth Lewis

Wayne State University Dissertations

Mitochondrial Fe-S cluster biosynthesis is accomplished within yeast utilizing the biophysical characteristics of the “Isu1” scaffold protein. As a member of a highly homologous protein family, Isu1 has sequence conservation with orthologs and a conserved ability to assemble [2Fe-2S] clusters. Regardless of species, scaffold orthologs can exist in both “disordered” and “structured” conformations and is directly related to conformations utilized during Fe-cofactor assembly. During assembly, the scaffold directs the delivery and the utilization of both Fe(II) and sulfide substrates in order to produce [2Fe-2S] clusters, however Zn(II) binding can alter the activity of the scaffold with stabilizing the protein in …

Functional Analysis Of Bacillus Anthracis Aspartate Transcarbamoylase And Dihydroorotase, Katelyn Leigh Schwager Silva

Wayne State University Theses

There are many enzymes required for efficient and proper pyrimidine biosynthesis. The two that are most important and were discussed in this thesis are aspartate transcarbamoylase (ATCase) and dihydroorotase (DHOase). Both play an important role in not only pyrimidine biosynthesis production, but also mechanistic regulation of de novo synthesis. Anthrax is an infection caused by Bacillus anthracis. Here we studied ATCase and DHOase in Bacillus Anthracis. In this thesis we understood the effects of the enzymes ATCase and DHOase on pyrimidine biosynthesis. Adequate inhibitors of these enzymes would result in cell death and could pose as a cure to infection …

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 …

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 …

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 …

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 In Vivo Activity Of Ribosome-Targeting Peptides And Aminoglycosides In Escherichia Coli, Nisansala Sarangi Thilakarathne Muthunayake

Wayne State University Dissertations

The development of short peptides that specifically bind to higher-order structures of ribosomal RNA is one promising way to address the problem of antibiotic resistance. However, the poor correlation between in vitro and in vivo activities of these peptides is one of the major questions in antibiotic peptide research. Therefore, one of the main objectives of this dissertation work was to utilize a plasmid-based system to in vivo express ribosome-targeting peptides and study their direct inhibitory effects on bacteria. A specific plasmid system was optimized to in vivo express oncocin, a prolin-rich antimicrobial peptide and its variants in bacteria. Our …

Functional Study Of Smyd2 Glutathionylation In Cardiomyocytes, Dhanushka Nalin Perera Munkanatta Godage

Wayne State University Dissertations

Reactive oxygen species (ROS) are important signaling molecules that contribute to the etiology of multiple muscle-related diseases, including cardiomyopathy and heart failure. There is emerging evidence that cellular stress can lead to destabilization of sarcomeres, the contractile unit of muscle. However, it is not completely understood how cellular stress or ROS induce structural destabilization of sarcomeres or myofibrils. Protein glutathionylation is one of the major protein cysteine oxidative modifications that play an important role in redox signaling and oxidative stress. In this report, we used a clickable glutathione approach in a cardiomyocyte cell line, and found that SET and MYND …

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 …

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 …

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 …

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 …

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 …

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 …

Phosphorylation Of Cytochrome C Threonine 28 Regulates Electron Transport Chain Activity In Kidney: Implications For Amp Kinase, Gargi Mahapatra, Ashwathy Varughese, Qinqin Ji, Icksoo Lee, Jenney Liu, Asmita Vaishnav, Christopher Sinkler, Alexandr A. Kapralov, Carlos T. Moraes, Thomas H. Sanderson, Timothy L. Stemmler, Lawrence I. Grossman, Valerian E. Kagan, Joseph S. Brunzelle, Arthur R. Salomon, Brian Fp Edwards, Maik HüTtemann

Biochemistry and Molecular Biology Faculty Publications

Mammalian cytochrome c (Cytc) plays a key role in cellular life and death decisions, functioning as an electron carrier in the electron transport chain and as a trigger of apoptosis when released from the mitochondria. However, its regulation is not well understood. We show that the major fraction of Cytc iso- lated from kidneys is phosphorylated on Thr28, leading to a par- tial inhibition of respiration in the reaction with cytochrome c oxidase. To further study the effect of Cytc phosphorylation in vitro, we generated T28E phosphomimetic Cytc, revealing supe- rior behavior regarding protein stability and its ability to degrade …

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 …

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 …

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 …

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 …

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 …

Mechanistic And Inhibitory Analysis Of Clostridium Difficile Associated Diseases, Brianna Marie Jackman

Wayne State University Theses

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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 …