Biochemistry Commons^™

Mechanism Elucidation And Inhibitor Discovery Against Serine And Metallo-Beta-Lactamases Involved In Bacterial Antibiotic Resistance, Orville A. Pemberton

USF Tampa Graduate Theses and Dissertations

The emergence and proliferation of Gram-negative bacteria expressing β-lactamases is a significant threat to human health. β-Lactamases are enzymes that degrade the β-lactam antibiotics (e.g., penicillins, cephalosporins, monobactams, and carbapenems) that we use to treat a diverse range of bacterial infections. Specifically, β-lactamases catalyze a hydrolysis reaction where the β-lactam ring common to all β-lactam antibiotics and responsible for their antibacterial activity, is opened, leaving an inactive drug. There are two groups of β-lactamases: serine enzymes that use an active site serine residue for β-lactam hydrolysis and metalloenzymes that use either one or two zinc ions for catalysis. Serine enzymes …

Disorder Levels Of C-Myb Transactivation Domain Regulate Its Binding Affinity To The Kix Domain Of Creb Binding Protein, Anusha Poosapati

USF Tampa Graduate Theses and Dissertations

Intrinsically disordered proteins (IDPs) do not form stable tertiary structures like their ordered partners. They exist as heterogeneous ensembles that fluctuate over a time scale. Intrinsically disordered regions and proteins are found across different phyla and exert crucial biological functions. They exhibit transient secondary structures in their free state and become folded upon binding to their protein partners via a mechanism called coupled folding and binding. Some IDPs form alpha helices when bound to their protein partners. We observed a set of cancer associated IDPs where the helical binding segments of IDPs are flanked by prolines on both the sides. …

Regulation Of Extracellular Signal-Regulated Kinase By Histone Deacetylase 6, Jheng-Yu Wu

USF Tampa Graduate Theses and Dissertations

Extracellular signal-regulated kinases 1/2 (ERK1/2) are important kinases regulating cell proliferation and cell migration, and have been established as therapeutic targets for cancer treatment. Previously, we found that ERK1 phosphorylates histone deacetylase 6 (HDAC6) to regulate its enzymatic activity. However, whether HDAC6 reciprocally modulates ERK1 activity is unknown. Here, we have discovered that ERK1/2 are acetylated proteins and shown that HDAC6 manipulates ERK1’s kinase activity via deacetylation. We demonstrated that both ERK1 and ERK2 interact with HDAC6 physically. We showed that the acetylation level of GST-ERK1/2 increased in a dose- and time-dependent manner upon treatment with a pan-HDAC inhibitor, Trichostatin …

Structure And Activity Of Metallo-Peptides, Christian C. Tang

USF Tampa Graduate Theses and Dissertations

Metal ions are ubiquitously found in all living systems and play vital roles in supporting life forms by performing an array of biological activities. Such biological activities include binding and transforming organic molecules, and also acting as active centers and cofactors for catalysis of various acid-base and redox reactions in biological system. The main focus in bioinorganic chemistry is to elucidate the structural and functional roles of metals in biological systems. Among all transition metal ions, Cu²⁺ and Fe³⁺ are especially versatile and important due to their abilities to go through redox efficiently.

This dissertation can be divided …

Bioaccumulation Of Metallic Trace Elements And Antioxidant Enzyme Activities In Apfelbeckia Insculpta (L. Koch, 1867) (Diplopoda: Callipodida) From The Cave Hadži-Prodanova Pećina (Serbia), Jelena Vranković, Slavica Borković-Mitić, Bojan Ilić, Milanka Radulović, Slaviša Milošević, Slobodan Makarov, Bojan Mitić

International Journal of Speleology

The concentration of 10 metallic trace elements or MTE (Cu, Fe, Zn, Mn, As, Hg, Pb, Cd, Ni, and Cr) was measured in specimens of the troglophilic millipede Apfelbeckia insculpta (L. Koch, 1867) and sediment of the cave Hadži-Prodanova Pećina in western Serbia. Some MTE, like Fe and Mn, displayed much higher concentrations compared to other elements, both in the sediment and in the body of A. insculpta. On the other hand, estimation of the bioaccumulation factor (BAF) in both males and females of A. insculpta showed values greater than 1 for xenobiotic elements compared to those that are essential. …

Mechanisms Of Ikbke Activation In Cancer, Sridevi Challa

USF Tampa Graduate Theses and Dissertations

Cancer is the second leading cause of death in the USA and it is expected to surpass heart diseases making it important to understand the underlying mechanisms of cancer. The efforts to target single signaling molecule showed little success in increasing the patient survival and it can be due to increased compensation for cell survival by alternative pathway activations. Hence comprehensive understanding of the alternative signaling pathways may help us treat cancer better. Chronic inflammation is attributed to increased risk of cancer and emerging studies show the growing importance of both canonical and non-canonical IκB kinases such as IKKα, IKKβ, …

The Effects Of Phytohormones And Isoprenoids In Dihydroartemisinin-Induced Dormancy In The Erythrocytic Stages Of Plasmodium Falciparum, Marvin Duvalsaint Duvalsaint

USF Tampa Graduate Theses and Dissertations

Our ability to control malaria has been challenged by increasing antimalarial resistance. Plasmodium falciparum undergoes dormancy in the blood stages which is hypothesized to be a means by which they are able to survive under drug pressure. This helps select for resistant parasites which grow following removal of drug. The mechanisms behind dormancy and the subsequent recrudescence are not fully understood but translating knowledge from related organisms which undergo a similar phenomenon might shed some light. Higher plants utilize dormancy during the early development stages to survive under unfavorable conditions, increasing fitness of the seedling and ensuring viability when this …

Quantitative Proteomic Investigation Of Disease Models Of Type 2 Diabetes, Mark Gabriel Athanason

USF Tampa Graduate Theses and Dissertations

PANcreatic DERived factor (PANDER, FAM3B) is a member of a superfamily of FAM3 proteins that are uniquely structured and strongly expressed from the endocrine pancreas and co-secreted with insulin. Unique animal models available to our lab have indicated that PANDER can induce a selective hepatic insulin resistant (SHIR) phenotype whereby insulin signaling is blunted yet lipogenesis is increased. The complexity of the biological networks involved with this process warranted the logical approach of employing quantitative mass spectrometry based proteomic analysis using stable isotope labeling of amino acids in cell culture (SILAC) to identify the global proteome differences between the PANDER …

Significance Of Pten Phosphorylation And Its Nuclear Function In Lung Cancer, Prerna Malaney

USF Tampa Graduate Theses and Dissertations

Phosphorylation mediated inactivation of PTEN leads to multiple malignancies with increased severity. However, the consequence of such inactivation on downstream functions of PTEN are poorly understood. Therefore, the objective of my thesis is to ascertain the molecular mechanisms by which PTEN phosphorylation drives lung cancer. PTEN phosphorylation at the C-terminal serine/threonine cluster abrogates its tumor suppressor function. Despite the critical role of the PTEN C-tail in regulating its function, the crystal structure of the C-tail remains unknown. Using bioinformatics and structural analysis, I determined that the PTEN C-tail is an intrinsically disordered region and is a hot spot for post-translational …

Regulation Of Palmitoylation Enzymes And Substrates By Intrinsically Disordered Regions, Krishna D. Reddy

USF Tampa Graduate Theses and Dissertations

Protein palmitoylation refers to the process of adding a 16-carbon saturated fatty acid to the cysteine of a substrate protein, and this can in turn affect the substrate’s localization, stability, folding, and several other processes. This process is catalyzed by a family of 23 mammalian protein acyltransferases (PATs), a family of transmembrane enzymes that modify an estimated 10% of the proteome. At this point in time, no structure of a protein in this family has been solved, and therefore there is poor understanding about the regulation of the enzymes and their substrates. Most proteins, including palmitoylation enzymes and substrates, have …

Tunable Nano-Delivery System For Cancer Treatment: A New Approach For Targeted Localized Drug Delivery, Rana Falahat

USF Tampa Graduate Theses and Dissertations

Localized drug delivery systems have been widely studied as potential replacements for conventional chemotherapy with the capability of providing sustained and controlled drug release in specific targeted sites. They offer numerous benefits over conventional chemotherapy such as enhancing the stability of embedded drugs and preserving their anticancer activity, providing sustained and controlled drug release in the tumor site, reducing toxicity and diminishing subsequent side effects, minimizing the drug loss, averting the need for frequent administrations, and minimizing the cost of therapy.

The aim of this study is to develop a localized drug delivery system with niosomes embedded in a chitosan …

Targeting Tau Degradation By Small Molecule Inhibitors For Treatment Of Tauopathies, Mackenzie Martin

USF Tampa Graduate Theses and Dissertations

Tauopathies are neurodegenerative diseases that affect millions of people around the world. Tauopathies include more than 20 neurodegenerative diseases. Some of the most common tauopathies are Alzheimer’s disease (AD), frontotemporal dementia (FTD), chronic traumatic encephalopathy (CTE), Pick’s disease, corticobasal degeneration, progressive supranuclear palsy (PSP), agyrophillic grain disease, and amyotrophic lateral sclerosis (ALS). These diseases can cause significant memory loss, behavioral changes, motor deficits and speech impairments. Tauopathies stem from accumulation of the microtubule associated protein tau (MAPT). Tau stabilizes microtubules and helps with axonal transport. In a disease state tau becomes hyperphosphorylated and truncated leading to its aggregation. More recently …

Cell Permeability Studies Of Aapeptides And Novel Molecular Probes For Ad, Ge Bai

USF Tampa Graduate Theses and Dissertations

Alzheimer's diseases(AD) has been discovered and under research for more than 70 years, However there is no cure for these progressive and devastating diseases. Based on the following hypothsis: Aß metabolite problem/over production result in the accumulation, and lead to aggregation is the cause of Alzheimer’s disease. AApeptide and Melatonin derivatives can bind to Aß and block the aggregation of β amyloid monomers, decrease the toxicity of Aß to neurons and slow the progressive of Alzheimer’s diseases. In addition, AApeptide which mimic transmembrane peptide Tat will have similar transmembrane function. We have set up our goals as follows: 1) Using …

Investigation Of Respiratory Syncytial Virus Structural Determinants And Exploitation Of The Host Ubiquitin System, Jillian Nicole Whelan

USF Tampa Graduate Theses and Dissertations

Respiratory syncytial virus (RSV) is a globally circulating, non-segmented, negative sense (NNS) RNA virus that causes severe lower respiratory infections. This study explored several avenues to ultimately expand upon our understanding of RSV pathogenesis at the protein level. Evaluation of RSV intrinsic protein disorder increased the relatively limited description of the RSV structure-function relationship. Global proteomics analysis provided direction for further hypothesis-driven investigation of host pathways altered by RSV infection, specifically the interaction between the RSV NS2 protein and the host ubiquitin system. NS2 primarily acts to antagonize the innate immune system by targeting STAT2 for proteasomal degradation. The goal …

Novel Techniques In Chemical Ecology To Examine Life Histories In Fishes, Orian Tzadik

USF Tampa Graduate Theses and Dissertations

Diet and movements in fishes are often logistically challenging to study. Trace element and stable isotope analyses have advanced these fields considerably, but are still constrained by methodological impediments, such as the tendency towards lethal sampling. Studying endangered fishes is particularly challenging as representative samples are difficult to obtain. However, the information gained from such studies is often critical to the recovery of endangered fishes as knowledge of life history attributes has the potential to greatly influence the success of management strategies.

I tested the viability of using fin rays in fishes as a non-lethal approach to study diet and …

Targeting Autopalmitoylation To Modulate Protein S-Palmitoylation, Laura Dawn Hamel

USF Tampa Graduate Theses and Dissertations

Palmitoylation refers to the covalent attachment of fatty acids, such as palmitate, onto the cysteine residues of proteins. This process may subsequently alter their localization and function. Nearly all of the enzymes that catalyze palmitoylation, zDHHC protein acyl transferases (PATs), are implicated in neurological disorders, infectious diseases, and cancer in humans. Of particular interest to those who study palmitoylation are Ras family GTPas and zDHHC9-GCP16, the zDHHC PAT that palmitoylates Ras proteins. Erf2-Erf4 is the zDHHC PAT that palmitoylates Ras proteins in Saccharomyces cerevisiae. Currently, there are no methods to therapeutically target palmitoylation for the treatment of disease. One …

Novel Enzyme Perspectives: Arylalkylamine N-Acyltransferases From Bombyx Mori & 1-Deoxy- D-Xylulose-5-Phosphate Synthase From Plasmodium Falciparum And Plasmodium Vivax, Matthew R. Battistini

USF Tampa Graduate Theses and Dissertations

This dissertation is dedicated to the research and investigation of novel enzymes and the methods used to study them, with physiological roles ranging from isoprenoid biosynthesis to neurotransmitter production. Using a combination of bioinformatics, recombinant cloning, enzymology, and proteomics, we have contributed to the understanding and exploration of several human illnesses, including malaria, cancer, and endocrine dysfunction.

Our first project involved studying the enzymes responsible for N-acylarylalkylamide biosynthesis in Bombyx mori. Very little is known how these potent signaling molecules are produced in vivo, however, one possible pathway is the direct conjugation of an acyl-CoA to a corresponding …

Structure Based Drug Design Targeting Bacterial Antibiotic Resistance And Alzheimer's Disease, Eric Michael Lewandowski

USF Tampa Graduate Theses and Dissertations

Structure based drug design is a rapidly advancing discipline that examines how protein targets structurally interact with small molecules, or known inhibitors, and then uses this information to lead inhibitor optimization efforts. In the case of novel inhibitors, protein structural information is first obtained via X-ray crystallography, NMR studies, or a combination of both approaches. Then, computational molecular docking is often used to screen, in silico, millions of small molecules and calculate the potential interactions they may have with the target protein’s binding pocket, in hopes of identifying novel low affinity inhibitors. By examining the interactions these small, low affinity, …

Gamma-Aapeptides As A New Class Of Peptidomimetics: Synthesis, Structures, And Functions, Haifan Wu

USF Tampa Graduate Theses and Dissertations

Peptidomimetics are synthetic oligomers that resemble the activities of peptides. Their advantages over peptides include high stability towards proteolysis and enormous chemical diversity. Over the past two decades, there have been extensive efforts to develop peptide mimics, such as beta-peptides, peptoids, D-peptides, etc. The research on peptidomimetics have led to many important applications in both medicinal and material science. In order to explore new functions, the discovery of peptidomimetics with novel frameworks is essential. We reported the synthesis and evaluation of a new class of peptidomimetics, termed as gamma-AApeptides. Previous studies of gamma-AApeptides have revealed that gamma-AApeptides are highly resistant …

Identification And Characterization Of N-Acyltransferase Enzymes That Are Involved In The Biosynthesis Of Fatty Acid Amides, Daniel Robert Dempsey

USF Tampa Graduate Theses and Dissertations

Fatty acid amides are an emerging family of bioactive lipids that consists of N-acylethanolamines, N-acylarylalkylamides, N-acylglycines, N-acyl amino acids, N-monoacylpolyamides, and primary fatty acid amides. Short chain fatty acid amides are products of inactivated biogenic amines such as dopamine, histamine, octopamine, and serotonin, whereas long chain fatty acid amides have been implicated in a number of physiological process such as the perception and inhibition of chronic pain through binding to their specific receptors. The most famous; therefore, the most studied long chain fatty acid amide is anandamide or also known as N-arachidonylethanolamine. The biosynthesis …

Regulation And Targeting Of The Fancd2 Activation In Dna Repair, Valentina Celeste Caceres

USF Tampa Graduate Theses and Dissertations

Fanconi anemia (FA) is a genome instability syndrome that is clinically manifested by bone marrow failure, congenital defects, and elevated cancer susceptibility. The FA pathway is known to regulate the repair of DNA interstrand crosslinks in part through DNA homologous recombination (HR) repair. Up to today 16 FA proteins have been discovered that may participate in the common pathway. Cells that have mutations in the FA genes are hypersensitive to DNA damaging agents and display chromosome instability. A key regulatory event in the FA pathway is monoubiquitination of FANCD2-FANCI heterodimer that is mediated by a multi-component E3 ubiquitin ligase complex …

Biosynthesis Of Long-Chain Fatty Acid Amides, Kristen A. Jeffries

USF Tampa Graduate Theses and Dissertations

The vast variety of long-chain fatty acid amides identified in biological systems is intriguing. The general structure of a fatty acid amide is R-CO-NH-X, where R is an alkyl group and X is derived from an immense variety of biogenic amines. Although structurally simple, the bioactivities of these molecules as signaling lipids are very diverse and have just recently begun to emerge in the literature. Interest in the long-chain fatty acid amides dramatically increased following the identification and characterization of one specific N-acylethanolamine, N-arachidonoylethanolamine (anandamide), as the endogenous ligand for the cannabinoid receptors in the mammalian brain. Since …

A Novel Role For Nf-Κb In Proximal T Cell Signaling, Crystina Bronk Watson

USF Tampa Graduate Theses and Dissertations

The interrogation of T cell signaling over the past fifty years has led to the discovery of amazingly intricate cascade networks and elaborate descriptions of individual proteins' domains and functions. A complex landscape has been rendered in which proteins relay messages from the extracellular ligation of the TCR by a cognate peptide loaded MHC via changes in sub-cellular location, phosphorylation, and binding affinities and partners to enact nuclear localization of three key transcription factors required for cellular effector function and proliferation: AP-1, NF-AT, and NF-κB. Dogma has favored activation of each of these transcription regulating elements to be a linear …

Eukaryotic Gene Expression Patterns Of Microorganisms In The Amazon River Plume Parallel The Biogeochemistry Of Plume Waters, Brian L. Zielinski

USF Tampa Graduate Theses and Dissertations

Unraveling the microbiological processes that occur as water travels from a river's mouth into the ocean is critical to understanding the role of river plumes in global biogeochemical cycles. Metranscriptomics, the gene expression of a whole community of organisms, was utilized to examine six stations along the Amazon River Plume (ARP) in 2010 to test thehypothesis that there were measurable differences in gene expression for key biogeochemical genes along the ARP. This body of work focuses on methods developed to identify which genes are biogeochemically important for a particular environment along extreme salinity, nutrient and community gradients in the ARP, …

Synthesis, Characterization And Mechanistic Studies Of Biomolecules@Mesomofs, Yao Chen

USF Tampa Graduate Theses and Dissertations

Encapsulation of biomolecules is of great interest to research advances related to biology, physiology, immunology, and biochemistry, as well as industrial and biomedical applications such as drug delivery, biocatalysis, biofuel, food and cosmetics. Encapsulation provides functional characteristics that are not fulfilled by free biomolecules and stabilizes the fragile biomolecules. In terms of biocatalysis, solid support can often enhance the stability of enzymes, as well as facilitate separation and recovery for reuse while maintaining activity and selectivity. Various kinds of materials have been used for encapsulation of biomolecules, among which, porous materials are an important group. Metal-organic frameworks (MOFs) have attracted …

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

USF Tampa Graduate Theses and Dissertations

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

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

USF Tampa Graduate Theses and Dissertations

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

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

USF Tampa Graduate Theses and Dissertations

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

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

The Cave Environment Influencing The Lipid Profile And Hepatic Lipogenesis Of The Fish Ancistrus Cryptophthalmus Reis, 1987 (Siluriformes: Loricariidae), Valquíria Aparecida Alves Bastos, Rodrigo Lopes Ferreira, Daniel Cardoso Carvalho, Marina Lages Pugedo, Luciana De Matos Alves Pinto

International Journal of Speleology

The metabolism of hypogean organisms is frequently molded by the cave environment traits, especially food scarcity. The aim of the present work was to evaluate the influence of such environment on lipid composition and hepatic lipogenesis in the fish Ancistrus cryptophthalmus. For this, the species was compared to an epigean population of the same species. A greater accumulation of total lipids was observed in the cave-dwelling fish (18.36 g/100 g tissue) compared to the surface fish (14.09 g/100 g tissue). The muscle fatty acid profile also varied between the populations. Arachidonic acid was only detected in the epigean fish, while …

Biochemical Aspects Of The Thermal Sensitivity And Energy Balance Of Polar, Tropical And Subtropical Teleosts, Eloy Martinez

USF Tampa Graduate Theses and Dissertations

The maintenance of a functional energy balance in ectothermic fauna could be challenging in a thermally disparate environment. Biochemical adaptations at the enzyme and membrane levels allows for a set compensatory mechanism that allow the individual to maintain an energetic surplus, thus allocating energy for growth and reproduction. The present work describes how the energetic machinery in the cell, particularly the mitochondrion, could be affected by temperature changes. More specifically, this work aimed to determine how environmental temperature affects the mitochondria energetic performance of fishes from disparate thermal regimes.

Mitochondrial ATP production efficiency was evaluated in fishes from polar, tropical …