Biochemistry, Biophysics, and Structural Biology Commons^™

Remarkable Features Of The Hotdog-Fold Thioesterases Involved In Phylloquinone (Vitamin K1) Biosynthesis, Joshua R. Widhalm

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Phylloquinone (vitamin K₁) is a bipartite molecule, consisting of a naphthoquinone ring attached to a phytyl side chain, that is synthesized by plants and certain cyanobacteria to serve as an electron carrier in photosystem I. The coupling of the ring and isoprenyl moieties relies on the cleavage of the CoA-thioester linkage with 1,4-dihydroxy-2- naphthoate (DHNA). It has long been a mystery if this hydrolysis is an enzymatic or chemical process. Using comparative genomics, protein biochemistry, genetics and metabolic profiling, we identified a cyanobacterial thioesterase responsible for the in vivo hydrolysis of DHNA-CoA. This enzyme bears a signature domain …

Extracellular Atp Acts On P2y2 Purinergic Receptors To Facilitate Hiv-1 Infection, Claire Séror, Marie-Therese Melki, Frederic Subra, Syed Qasim Raza, Marlene Bras, Hela Saïdi, Roberta Nardacci, Laurent Voisin, Audrey Paoletti, Frederic Law, Isabelle Martins, Alessandra Amendola, Ali A. Abdul-Sater, Fabiola Ciccosanti, Olivier Delelis, Florence Niedergang, Sylvain Thierry, Najwane Said-Sadier, Christophe Lamaze, Didier Métivier, Jerome Estaquier, Gian Maria Fimia, Laura Falasca, Rita Casetti, Nazanine Modjtahedi, Jean M. Kanellopoulos, Jean-Francois Mouscadet, David M. Ojcius, Mauro Piacentini, Marie-Lise Gougeon, Guido Kroemer, Jean-Luc Perfetini

All Dugoni School of Dentistry Faculty Articles

Extracellular adenosine triphosphate (ATP) can activate purinergic receptors of the plasma membrane and modulate multiple cellular functions. We report that ATP is released from HIV-1 target cells through pannexin-1 channels upon interaction between the HIV-1 envelope protein and specific target cell receptors. Extracellular ATP then acts on purinergic receptors, including P2Y2, to activate proline-rich tyrosine kinase 2 (Pyk2) kinase and transient plasma membrane depolarization, which in turn stimulate fusion between Env-expressing membranes and membranes containing CD4 plus appropriate chemokine co-receptors. Inhibition of any of the constituents of this cascade (pannexin-1, ATP, P2Y2, and Pyk2) impairs the replication of HIV-1 mutant …

Attenuated Total Reflection Infrared Spectroscopy (Atr-Ir) As An In Situ Technique For Dissolution Studies, Abe S. Kassis

Seton Hall University Dissertations and Theses (ETDs)

No abstract provided.

The Role Of The Androgen Receptor Cofactor P44/Wdr77 In Astrocyte Activation, Bryce H. Vincent

Dissertations and Theses (Open Access)

Astrogliosis is induced by neuronal damage and is also a pathological feature of the major aging-related neurodegenerative disorders. The mechanisms that control the cascade of astrogliosis have not been well established. In a previous study, we identified a novel androgen receptor (AR)-interacting protein (p44/WDR77) and found that it plays a critical role in the control of proliferation and differentiation of prostate epithelial cells. In the present study, we found that deletion of the p44 gene in the mouse brain caused accelerated aging with dramatic astrogliosis. The p44/WDR77 is expressed in astrocytes and loss of p44/WDR77 expression in astrocytes leads to …

The Role Of Cancer-Associated Fibroblasts In Lung Tumorigenesis, Jonathon D. Roybal

Dissertations and Theses (Open Access)

The extracellular milieu is rich in growth factors that drive tumor progression,but the mechanisms that govern tumor cell sensitivity to those ligands have notbeen fully defined. In this study, we address this question in mice that developmetastatic lung adenocarcinomas through the suppression of the microRNA-200 (miR-200) family. Cancer-associated fibroblasts (CAF) enhance tumorgrowth and invasion by secreting VEGF-A that binds to VEGFR1, a processrequired for tumor growth and metastasis in mice and correlated with a poorprognosis in lung adenocarcinoma patients. In this study, we discovered thatmiR-200 blocked CAF-induced tumor cell invasion by directly targetingVEGFR1 in tumor cells. In the context of …

Echogenic Liposomes For Nitric Oxide Delivery And Breast Cancer Treatment, Soo Yeon Lee Female

Dissertations and Theses (Open Access)

Liposomes, also known as nontoxic, biodegradable, and non-immunogenic therapeutic delivery vehicles, have been proposed as a carrier for drugs and antitumor agents in cancer chemotherapy. Echogenic liposomes (ELIP) have the potential to entrap air or bioactive gas to enhance acoustic reflectivity in ultrasound and are used as a contrast agent. The innovative part of this study is based on a novel concept to encapsulate nitric oxide (NO) gas into ELIP, deliver it to breast cancer cells, and control its release via direct ultrasound exposure. Studies on the effect of NO in tumor biology have shown that a high levels of …

Downregulation Of Pax2 Suppresses Ovarian Cancer Cell Growth, Huijuan Song

Dissertations and Theses (Open Access)

PAX2 is one of nine PAX genes regulating tissue development and cellular differentiation in embryos. PAX2 promotes cell proliferation, oncogenic transformation, cell-lineage specification, migration, and survival. Unattenuated PAX2 has been found in several cancer types. We therefore sought to elucidate the role of PAX2 in ovarian carcinomas. We found that PAX2 was expressed in low-grade serous, clear cell, endometrioid and mucinous cell ovarian carcinomas, which are relatively chemoresistant compared to high grade serous ovarian carcinomas. Four ovarian cancer cell lines, RMUGL (mucinous), TOV21G (clear cell), MDAH-2774 (endometrioid) and IGROV1 (endometrioid), which express high-levels of PAX2, were used to study the …

Dissecting The Interaction Between P53 And Trim24, Aundrietta D. Duncan

Dissertations and Theses (Open Access)

Dissecting the Interaction of p53 and TRIM24

Aundrietta DeVan Duncan

Supervisory Professor, Michelle Barton, Ph.D.

p53, the “guardian of the genome”, plays an important role in multiple biological processes including cell cycle, angiogenesis, DNA repair and apoptosis. Because it is mutated in over 50% of cancers, p53 has been widely studied in established cancer cell lines. However, little is known about the function of p53 in a normal cell. We focused on characterizing p53 in normal cells and during differentiation. Our lab recently identified a novel binding partner of p53, Tripartite Motif 24 protein (TRIM24). TRIM24 is a member of …

Mechanisms Of Adenovirus-Mediated Autophagy, Erin White

Dissertations and Theses (Open Access)

A patient diagnosed with a glioma, generally, has an average of 14 months year to live after implementation of conventional therapies such as surgery, chemotherapy, and radiation. Glioblastomas are highly lethal because of their aggressive nature and resistance to conventional therapies and apoptosis. Thus other avenues of cell death urgently need to be explored. Autophagy, which is also known as programmed cell death type II, has recently been identified as an alternative mechanism to kill apoptosis- resistant cancer cells. Traditionally, researchers have studied how cells undergo autophagy during viral infection as an immune response mechanism, but recently researchers have discovered …

Investigations Of The Ppi-Dependent Acetate Kinase From The Parasite Entamoeba Histolytica, Matthew Fowler

All Dissertations

Acetate, a short-chain fatty acid that plays a key role in all domains of life, can be utilized as a carbon source or excreted as a product of metabolism. Acetate kinase (ACK), a member of the acetate and sugar kinase-Hsp70-actin (ASKHA) enzyme superfamily, is responsible for the reversible phosphorylation of acetate to acetyl phosphate utilizing ATP as the phosphoryl donor. Acetate kinases are ubiquitous in the Bacteria, found in one genus of Archaea, and are also present in microbes of the Eukarya. A partially purified ACK which can utilize pyrophosphate (PP_i) as the phosphoryl donor in the acetyl …

Studies Of The Distinguishing Features Of Nadph:2-Ketopropyl-Coenzyme M Oxidoreductase/Carboxylase, An Atypical Member Of The Disulfide/ Oxidoreductase Family Of Enzymes, Melissa A. Beighley-Kofoed

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The metabolism of propylene in Xanthobacter autotrophicus occurs via epoxypropane formation and subsequent metabolism by a three-step, four-enzyme pathway, utilizing the atypical cofactor Coenzyme M (CoM) to form acetoacetate. The last step in the epoxide carboxylase pathway is catalyzed by a distinctive member of the disulfide oxidoreductase (DSOR) family of enzymes, NADPH:2-ketopropyl CoM oxidoreductase/carboxylase (2-KPCC). 2-KPCC catalyzes the unorthodox cleavage of a thioether bond and successive carboxylation of the substrate. The focus of the research presented in this dissertation aims to elucidate the details of 2-KPCC that allow it to perform chemistry unconventional for typical DSOR members. Sitedirected mutagenesis was …

Glutaredoxin 2 Prevents H2o2-Induced Cell Apoptosis By Protecting Complex I Activity In The Mitochondria, Hongli Wu, Kuiyi Xing, Marjorie F. Lou

School of Veterinary and Biomedical Sciences: Faculty Publications

Glutaredoxin 2 (Grx2) belongs to the oxidoreductase family and is an isozyme of glutaredoxin 1 (Grx1) present in the mitochondria, however its function is not well understood. The purpose of this study is to evaluate the potential anti-apoptotic function of Grx2 by examining its ability to protect complex I in the mitochondrial electron transport system using human lens epithelial cells as a model. We found that cells treated with 200 μM hydrogen peroxide (H2O2) for 24 h exhibited decreased viability and became apoptotic with corresponding Bax up-regulation, Bcl-2 down-regulation, caspase 3 activation and mitochondrial cytochrome c leakage. Grx2 over-expression (OE) …

Preparation And X-Ray Crystallographic Studies Of Copper N-Methylimidazole Complexes With Substituted N-Phthaloylalaninato Ligands, Mohit Singhal

Theses, Dissertations and Culminating Projects

Quasiracemates contain two molecules (or ions) of opposite handedness, in which one enantiomer has a substitution of a chemically different, but similarly shaped group. Metal based complexes that are enantiomeric, racemic and quasiracemic were synthesized. Racemic metal compounds are synthesized from equimolar concenteration of chemically identical ligands having both handedness (R and S). Quasiracemic metal complexes were synthesized from two stercially similar, but chemically different ligands, and these complexes tend to mimic the centrosymmetric pattern in racemic metal complexes. This project was begun by previous master’s student, Hiral Patel, to study the crystal packing of metal based quasiracemic complexes, and …

Changes In Expression Of Akt Pathway Proteins Following Treatment With Rg3 In Vitro, Kathryn Schalkoff

All Theses

To assess changes in AKT pathway signaling, a recombinant protein of the G3 domain of rat laminin-5 (rG3) that specifically binds the alpha subunit of integrins α6β1 and α6β4 expressed on cancer cells (e.g., MDA-MB-231) was produced. This recombinant protein is believed to interrupt the intracellular signaling events of the AKT pathway, causing a decrease in proliferation and survival of cells after treatment. Viability assays confirmed an apoptotic effect of rG3 on cells in a dose-dependent manner. However, data from gene expression studies of Caspase-9, GRB10, and CDKNIB proved non-conclusive that rG3 is acting upon gene expression, leading to the …

Lafora Disease E3-Ubiquitin Ligase Malin Is Related To Trim32 At Both The Phylogenetic And Functional Level, Carlos Romá-Mateo, Daniel Moreno, Santiago Vernia, Teresa Rubio, Travis M. Bridges, Matthew S. Gentry, Pascual Sanz

Molecular and Cellular Biochemistry Faculty Publications

BACKGROUND: Malin is an E3-ubiquitin ligase that is mutated in Lafora disease, a fatal form of progressive myoclonus epilepsy. In order to perform its function, malin forms a functional complex with laforin, a glucan phosphatase that facilitates targeting of malin to its corresponding substrates. While laforin phylogeny has been studied, there are no data on the evolutionary lineage of malin.

RESULTS: After an extensive search for malin orthologs, we found that malin is present in all vertebrate species and a cephalochordate, in contrast with the broader species distribution previously reported for laforin. These data suggest that in addition to forming …

Sphingosine-1-Phosphate In Mast Cell-Mediated Allergic Responses, Megan Price

Theses and Dissertations

Mast cells play a critical role in both acute and chronic inflammation and mature in peripheral tissues from bone marrow-derived progenitors that circulate in the blood as immature precursors. Mast cell progenitors are likely to encounter the serum-borne bioactive sphingolipid metabolite, sphingosine-1-phosphate (S1P), during migration to target tissues. Mast cells developed from human cord blood-derived progenitors cultured with stem cell factor (SCF) alone express intragranular tryptase (MCT), the phenotype predominant in the lung. S1P accelerated the development of cord blood-derived mast cells (CB-MCs) and strikingly increased the numbers of mast cells expressing chymase. These mast cells have functional FcepsilonRI, and …

Structural Basis For Thermal Stability Of Thermophilic Trmd Proteins, Jamar Uzzell

Theses and Dissertations

Thermal stability of theG37 tRNA methyltransferase proteins from Thermotoga maritima and Aquifex aeolicus have been compared using Differential Scanning Calorimetry. It was shown that the Thermotoga protein is remarkably stable and is denatured at temperatures in excess of 100 degrees Centigrade. The Aquifex aeolicus protein was less stable, denaturing broadly at temperatures between 55oC and 100oC. In contrast, the mesophilic E. coli protein was completely denatured at 55oC. Enzymatic activity of the proteins was measured at various temperatures. Both the Thermotoga and Aquifex enzymes are active at ambient temperatures, and display a significant decrease in activity when the temperature is …

3d Picture Of The Syk-Vav1 Protein Complex: Tracking The B-Cell Signal One Complex At A Time, Dan I. Piraner

The Journal of Purdue Undergraduate Research

Protein signaling is the key method by which cells recognize a stimulus from their environment and convert it into a response. Signaling occurs in many forms: hormones, growth factors, and even proteins may act as signals from the environment. The response to their detection must be carried from the cell surface, where the signal is detected, to the nucleus, where the cell alters its DNA expression. This study analyzes one component in the signaling pathway of Spleen Tyrosine Kinase (Syk). The Syk protein receives a signal from B-cell receptors and amplifies it, resulting in an adaptive immune response and the …

Combating Bioterrorism: Purification And Structural Analysis Of The E3 Proteins Of The Venezuelan Equine Encephalitis Virus And The Chikungunya Virus, Tyshia Gwin

The Journal of Purdue Undergraduate Research

Outbreaks of the Venezuelan Equine Encephalitis Virus (VEEV) and the Chikungunya Virus (CHIKV) continue to emerge in Central and South America, Africa, and Asia, but there are currently no vaccines or anti-virals for these viruses. Given their ease of transmission, debilitating symptoms, and genetic alterability, VEEV and CHIKV have great potential for development into biological weapons. Therefore, there is an urgent need to determine possible methods of treatment or prevention. One possibility of prevention lies in determining the structure and biological function of the E3 protein that plays a key role in the infectivity of the viruses. In this research, …

Role Of Tyk2 In The Development Of Beige Cells, Samantha Umali

Theses and Dissertations

Obesity results from an excess of adipose tissue and is a major risk factor for type 2 diabetes, cardiovascular disease, and cancer. Adipose tissue exists in two main forms: white adipose tissue (WAT), which stores energy as triglycerides, and brown adipose tissue (BAT), which dissipates stored energy as heat. White adipose tissue is composed of several subcutaneous and visceral depots, each possessing distinct molecular and functional characteristics. Brown-like adipocytes can emerge in WAT depots in response to cold or beta-adrenergic stimulation. These cells have been called “beige” or “brite” (brown-in-white) cells. The reduction of obesity in mice treated with beta-adrenergic …