Biochemistry Commons^™

Local Modulation And Measurement Of Macrophage-Derived Bioactive Proteins From Implanted Biomaterials In Rat, Geetika Bajpai

Graduate Theses and Dissertations

Fibrosis around the implanted medical devices is a severe problem that can plague long-term device reliability. Activation of macrophage phenotype (macrophage polarization) has emerged as a new and possible means for reducing fibrosis in the fields of biomaterials and regenerative medicine. Macrophages are phagocytic cells that respond to microenvironmental cues that direct their phenotype. Macrophage activation has been widely studied in mouse and human in the context of tumor biology, yet little information is available regarding how macrophage activation could be used in a biomaterials context. Further, rats rather than mice are the common subjects in biomaterials experiments. A significant …

Resonant Two-Photon Ionization Studies Of Non Covalent Interactions In Halo Aromatic Clusters And Spin-Orbit Coupling Modeling In Mono-Halocarbenes, Silver Nyambo

Dissertations (1934 -)

Non-covalent interactions in halobenzenes (PhX) (X=F, Cl, Br) and phenylamine (C₆ H₅ NH₂ ) have been studied here using resonance two-photon ionization (R2PI) spectroscopy combined with a linear TOF-mass spectrometer. Their interaction with polar molecules in form of ammonia (NH ₃ ) and trifluorohalomethanes (CF₃ X) has also been studied. DFT and TD-DFT calculations using M06-2X functionals were carried out on different cluster conformations to compliment experimental results. A general trend of broadness in homogenous dimers (PhX)₂ , has been attributed to mainly the presence of multiple cluster isomers and Frank-Condon activity in the low …

New Strategies To Reveal Protein Candidates In Protein-Protein Interactome Study, Meng-Chieh Chen

Open Access Theses

Comprehensive protein-protein interaction network analysis can help reveal protein functions in a system-wide manner. A reliable knowledgebase of interaction networks is not only important for selecting the candidates for drug therapies, but also for evaluating the disease risk. In current interaction databases, 322579 interactions comprised of 56460 proteins have been reported (statistical analysis from APID: Agile Protein Interaction DataAnalyzer; http://bioinfow.dep.usal.es/apid/index.htm). The huge datasets are contributed mainly by yeast -two -hybrid (Y2H) screening and affinity-purification followed by mass spectrometry (AP-MS). High false positive rates and failing to cover certain interaction categories are the limitations of these two methods. Here, we developed …

1,25-Dihydroxyvitamin D Alters Lipid Metabolism And Epithelialto- Mesenchymal Transition In Metastatic Epithelial Breast Cancer Cells, Alle Nicole Barnard

Open Access Theses

Evidence suggests that high vitamin D status (marked by serum 25-hydroxyvitamin D, 25(OH)2 D) is associated with a decreased risk of breast cancer. It has been established that 1,25-dihydroxyvitamin D (1,25(OH) 2 D) can alter glycolysis and the Krebs cycle of breast cancer cells (Jiang et al., 2010; Zheng et al., 2013) but little information is available on 1,25(OH) 2 D's alterations of lipid metabolism in breast cancer cells. Thus, the current research investigates if there was an effect of 1,25(OH) 2 D on proteins that regulate lipid metabolism in MCF10A, MCF10A-ras, MCF10CA1h, and MCF10CA1a epithelial breast cancer cells. While …

Developing An Unstructured Model To Investigate The Effect Of Ethanol On Product Yields For Glucose And Xylose Cofermentation In Saccharomyces Cerevisiae 424a (Lnh-St), Shane D. Clingenpeel

Open Access Theses

Production of bio-ethanol from lignocellulose requires the efficient fermentation of glucose and xylose, even in the presence of inhibitors. The desired product, ethanol itself, will inhibit the fermentation. A further understanding of how ethanol affects the organism is critical to overcoming its inhibition.

This thesis evaluated the effect of ethanol on the cofermentation of glucose and xylose in two different cases. The first case had an unstructured model created for Saccharomyces cerevisiae 424A (LNH-ST), a genetically modified strain of yeast capable of cofermenting glucose and xylose. The differential equations were based around sugar consumption, and the product yields were investigated …

Monodentate, Bidentate And Photocrosslinkable Thiol Ligands For Improving Aqueous Biocompatible Quantum Dots, Hiroko Takeuchi

Graduate Theses and Dissertations

Water-soluble Quantum Dots (QDs) are highly sensitive fluorescent probes that are often used to study biological species. One of the most common ways to render QDs water-soluble for such applications is to apply hydrophilic thiolated ligands to the QD surface. However, these ligands are labile and can be easily exchanged on the QD surface, which can severely limit their application. As one way to overcome this limitation while maintaining a small colloidal size of QDs, we developed a method to stabilize hydrophilic thiolated ligands on the surface of QDs through the formation of a crosslinked shell using a photocrosslinking approach. …

Biochemical And Biophysical Studies Of Novel Features Of Ras-Related Protein Interactions, Kyla Marie Morinini Morris

Graduate Theses and Dissertations

The Ras superfamily of G-proteins are of great research interest for structure-function relationships among proteins as they act as molecular switches in the regulation of various biochemical reactions in the cell. They are regulated by protein-protein interactions targeted to the highly flexible switch regions. Mutations in G-proteins or their effectors may cause alterations in structure and/or function that can lead to overactivity.

The Ras-related protein Cell division cycle 42 (Cdc42) is important in regulating cell-signaling processes. The T35A mutation in Cdc42 leads to a decrease in flexibility of the Switch I region responsible for effector binding. The kinetics of the …

Gas-Phase Covalent And Non-Covalent Ion/Ion Chemistry Of Biological Macromolecules, John Robert Stutzman

Open Access Dissertations

Gas-phase ion/ion chemistry involves the interaction of oppositely charged ions inside of the mass spectrometer. During this gas-phase chemistry, particle transfer (i.e., proton and electron) or synthesis can occur at rapid reaction rates. Particle transfer represents a mature area of ion/ion chemistry, while selective covalent modification represents a fairly new area of gas-phase chemistry. Gas-phase covalent chemistry is based on traditional solution phase organic chemistry.

The work demonstrated in this dissertation greatly involves gas-phase covalent and non-covalent Schiff base chemistry on peptide and protein ions. The reagent dianion, 4-formyl 1,3-benzene disulfonic acid, has been used to covalently modify unprotonated primary …

Design, Synthesis, And Evaluation Of Molecular Inhibitors For Biologically Relevant Enzymes, Sarah Emma St. John

Open Access Dissertations

The work in this thesis details the design, synthesis, and biological evaluation of molecular inhibitors for the inhibition of biologically relevant enzymes. The first three chapters of this thesis concern the polyphenol resveratrol and its inhibition of the quinone reductase 2 (QR2) enzyme. The work on this subject resulted in the complete design, synthesis, biological and structural evaluation of a second generation library of resveratrol analogues. From this work we identified a novel resveratrol analogue that inhibits QR2 in a previously unknown binding orientation. The fourth chapter of this thesis details the de novo design of molecules for the inhibition …

Characterization Of Caxck31, A Bacterial Calcium/Proton Antiporter, Marc Robert Ridilla

Open Access Dissertations

To better understand a class of transporters known as Calcium/Cation Antiporters (CaCAs), the bacterial calcium/proton antiporter CAXCK31 was purified and characterized. New methods were developed for its heterologous overexpression and purification. These methods help to define stress responses to toxic membrane overproduction in E. coli and may be broadly applicable to studies of membrane proteins. The results from a variety of biochemical and biophysical experiments demonstrated that CAXCK31 exists as a dimer in the membrane and can be purified in the dimeric state. The methods used include chemical cross-linking, FRET, and SEC-MALS. In addition, various transport properties of CAXCK31, including …

The Termite Digestome: Understanding The Digestive Physiology Involved In Lignocellulosic Biomass Degradation, Zachary John Karl

Open Access Dissertations

The purpose of this research was to advance the understanding of lower termite digestive physiology and discover potential biocatalysts that can aid in the degradation of lignocellulosic biomass. Various protein characterization and gene expression methods were used throughout this research in order to accomplish these objectives. The results of this dissertation indicate that: 1) termites and their symbionts act in a synergistic manner to degrade biomass in vitro, 2) the host fraction of the gut (i.e., foregut and midgut) is the likely site of glucose absorption, 3) the termite and its symbionts contribute specific enzymes to the digestive process, 4) …

Development Of Tyrosine Kinase Peptide Biosensors And Methods For Detection, Andrew Michael Lipchik

Open Access Dissertations

New methods to monitor tyrosine kinase activity are critical for studying kinases in cell biology, drug discovery and the clinic. Peptide-based biosensors for detection of kinase activity utilitize a kinase specific artificial peptide substrate, which can report intercellular kinase activity through the incorporation of phosphate.

An artificial Syk substrate peptide was developed and incorporated with other functional modules to produce a Syk biosensor. These modules included a biotin-tag for affinity capture, a photo-cleavable amino acid to allow release of the substrate from the delivery module and the cell penetrating peptides TAT. A live cell kinase assay utilizing this biosensor was …

Characterization Of The Specificity And Functions Of The Protein Phosphatase Cdc14, Christie Eissler

Open Access Dissertations

Protein phosphorylation is perhaps the most ubiquitous posttranslational modification in eukaryotes and recent studies suggest that upwards of 75% of human proteins are phosphorylated. Many proteins are phosphorylated at multiple sites, often controlled by multiple kinases and phosphatases. Multisite phosphorylation can differentially affect the functional and regulatory cellular outcomes. For example, dephosphorylation of a protein at a particular site may inhibit nuclear localization of a protein while dephosphorylation of a different site may be necessary for enzymatic activation of a protein. Thus, multisite protein phosphorylation can complicate our understanding of the biological significance and the functional consequences of protein phosphorylation. …

Structural And Functional Characterization Of The Endosome-Associated Deubiquitinating Enzyme Amsh, Christopher Williamson Davies

Open Access Dissertations

The endosomal sorting complexes required for transport (ESCRT) machinery is a ubiquitin-dependent molecular mechanism made of up of four individual complexes: ESCRT-0, -I, -II, III, that is necessary for regulating the degradation of cell surface receptors directed towards the lysosome. Not only are the ESCRTs implicated in endosomal sorting and trafficking of proteins, its members also have roles in other important biological processes such as: cytokinesis, HIV budding, transcriptional regulation, and autophagy. As a function of its involvement in several processes throughout the cell, the ESCRT machinery is implicated in a wide variety of diseases including cancer, neurological disease, bacterial …

Structure-Function Relationship Of The Ligand-Binding Domain Of The Fibroblast Growth Factor Receptor, Ryan Thurman

Graduate Theses and Dissertations

The interactions between FGF and fibroblast growth factor receptors are responsible for the regulation of key cellular processes. FGF is important in both germ cell and embryonic developments. FGF continues to play important roles during adulthood by regulating embryogenesis, cell differentiation, and wound healing (1-7). The regulations of these cellular events are initiated through FGF binding to the fibroblast growth factor receptors. The complex formed by FGF and the receptor involves a key interaction with heparin. Through interactions with heparin, the FGF, FGFR and Heparin form a 2:2:2 complex (8). This complex formation results in autophosphorylation in the tyrosine kinase …

Design, Development, And Characterization Of Novel Antimicrobial Peptides For Pharmaceutical Applications, Yazan H. Akkam

Graduate Theses and Dissertations

Candida species are the fourth leading cause of nosocomial infection. The increased incidence of drug-resistant Candida species has emphasized the need for new antifungal drugs. Histatin 5 is a naturally occurring human salivary antifungal peptide and the first line of defense against infections of the oral cavity. This research has focused on understanding the activity of histatin 5, and subsequently designing novel peptides that may serve as models for the further development of therapeutics to treat fungal infection.

This objective has been achieved in three steps: studying the structural requirement of histatin 5 involved in antifungal activity, the identification of …

Oxidation Of Thrombomodulin Methionine 388 In Cigarette Smokers, Samrat B. Thapa

Graduate Theses and Dissertations

This work tested the hypothesis that oxidation of methionine 388 in thrombomodulin is higher in cigarette smokers, and thus a likely contributor towards the hypercoagulable state in smokers. Thrombomodulin, a protein cofactor found on endothelial cell surfaces, regulates the activity of thrombin. Thrombin bound to thrombomodulin no longer converts fibrinogen to fibrin, but instead activates Protein C which, in turn, stops the coagulation cascade by inactivation of clotting factors. The oxidation of methionine 388 of thrombomodulin has been shown in vitro to dramatically decrease the anticoagulant cofactor activity of thrombomodulin. The blood of cigarette smokers is more prone to clot …

Effects Of Ergot Alkaloids And Bovine Bodily Fluids On Cytochrome P450 Activity, Nicholas Scott Ezell

Graduate Theses and Dissertations

This thesis evaluates the Promega^TM P450-Glo assay (Promega^TM V9800) as a tool for quantifying ergot alkaloid concentration. Current techniques used for detection of ergot alkaloids are slow and expensive, do not detect all ergot alkaloids, or are not effective on bovine bodily fluids. The first study was conducted to determine effects of commercial ergot alkaloids (n = 6; 0 - 400 μM) on the Promega^TM P450-Glo assay. Cytochrome P450 (CYP450) activity in assay had a differential response to each ergot alkaloid and concentration. As concentrations of ergotamine, dihydroergotamine, ergocornine, and ergocryptine increased CYP450 activity was inhibited (P …

Capillary And Microchip Electrophoresis For The Monitoring Of Disease Causing Amyloid Proteins, Elizabeth Nancy Pryor

Graduate Theses and Dissertations

The detection of oligomers and aggregates formed by two amyloid proteins, insulin and amyloid-beta (AB), is of particular importance due to the role which these species play in Diabetes and Alzheimer's disease, respectively. However, existing techniques are limited in the ability to detect insulin and AB; oligomers due to the fact that these early aggregates are transient, present at low concentrations, and difficult to isolate. Improvements must be made to existing techniques or alternative techniques must be explored in order to identify and quantify the size of these oligomeric and aggregate species without disrupting their structure.

Capillary and microchip electrophoresis …

Part I - A Study Of The Formation Of Carbenes By Elimination Of Α-Bromosilanes And Application Toward The Synthesis Of Transition Metal Complexed Quinone Methide Analogs. Part Ii - Development Of Novel 7-Membered Ring Carbene Ligands For Palladium Catalyzed Cross Coupling Reactions., Christian Michael Loeschel

Graduate Theses and Dissertations

In part I, we wish to report our approaches toward transition metal complexed ortho-quinone methide analogs. ortho-Quinone Methides are a class of highly reactive compounds with a wide range of chemical and biological applications. Previously, a stable iron complexed benzannulated 5-membered ring quinone methide analog was reported by Allison and Neal27. Herein, we report our approaches to improve the reactivity of that system by removing benzannulation as well as changing the metal from iron to manganese and rhenium.

Furthermore, a methodological study on generating carbenes under mild conditions by elimination of α-halosilanes and its application towards metal complexed quinone methide …

Investigations Of Protein-Lipid Interactions In Model Membranes: Influence Of Aromatic Anchoring Residues And Buried Polar Residues, Nick Gleason

Graduate Theses and Dissertations

To investigate in detail the interactions between transmembrane proteins and the lipid bilayers in which they are constituted, designed model peptides with selective isotopic labels were synthesized and analyzed by means of solid-state deuterium NMR spectroscopy. Starting from the well-characterized model peptide GWALP23, acetyl-GGALW(LA)6LWLAGA-amide, several Trp to Tyr mutations were compared to evaluate their respective interfacial anchoring abilities. It was found that Tyr, substituted on either or both termini, can effectively anchor the transmembrane alpha-helix, which then adopts a similar transmembrane topology in a range of bilayer thicknesses. Nevertheless, a consistent ~10° shift in tilt direction (helix rotation) is observed …

An Analysis Of The Redox Properties And Stability Of Chlamydomonas Reinhardtii Cytochrome F, Cytochrome C6, And Mutants Thereof, Nicole Lynn Vanderbush

Graduate Theses and Dissertations

This body of work presents mutagenesis studies conducted on two c-type cytochromes from Chlamydomonas reinhardtii. Cytochrome f, a unique c-type cytochrome, is investigated in regards to its redox potential, the dependence of the redox potential, and the thermal stability of the protein. The mutations made were Y1F, Y9F, Y160F, Y160L, R156L, and R156K. The residues that were mutated surround the heme. It was found that, relative to the wild-type, only the Y160L and R156 mutants showed any difference in midpoint potential at pH 7. Wild-type and mutants both had a midpoint potential that was dependent upon pH indicating that none …

Characterization Of Novel Histone H2b Mutants Associated With Chromosome Segregation Defects In Saccharomyces Cerevisiae, Thiruchelvam Rajagopal

Graduate Theses and Dissertations

Histones are small basic proteins that associate with DNA to form the basic unit of chromatin, the nucleosome. Histones H3 and H4 form a tetramer that is bound by two H2A-H2B dimers to form the histone octamer, to which approximately 146 bp of DNA wrap around to form the nucleosome. High resolution structural information and recent advances in the understanding of histone post-translational modifications have illuminated the many regulatory functions chromatin exerts in the cell, from the transcriptional control of gene expression to chromosome segregation. However, the specific role that histones play in these processes is not well understood. Previous …

Visualizing The Spatial Localization Of Active Matrix Metalloproteinases (Mmps) Using Maldi Imaging Ms, Sasirekha Muruganantham

Graduate Theses and Dissertations

Biomaterial implantation induces the foreign body response (FBR). Development of longer-term implants relies on the thorough understanding of the FBR. The progression of the FBR is regulated by a number of biomolecules including cytokines, chemokines, and matrix metalloproteinases (MMPs). The nature of the FBR requires the spatial and temporal regulation of these mediators. MMPs are an extremely large and diverse group of enzymes that play key roles in regulating the FBR. Precise spatiotemporal regulation of MMPs defines their proteolytic activities. The aim of this project is to develop a new bioanalytical method to visualize the localization of active MMPs at …

The Role Of Albino3 And The Lipid Environment In Chloroplast Signal Recognition Particle Targeting, Nathan Lewis

Graduate Theses and Dissertations

Signal recognition particles (SRPs) in pro- and eukaryotes function in cotranslational targeting of nascent poplypeptides to an SRP receptor at the target membrane. A unique chloroplast SRP (cpSRP) functions post-translationally to direct light-harvesting chlorophyll-binding proteins (LHCPs) to the receptor cpFtsY at the thylakoid membrane for LHCP insertion in a process involving the integral membrane protein Albino3 (Alb3) and requiring GTP. Work here focuses on understanding cpSRP targeting events at the thylakoid membrane, specifically those involving Alb3 and the lipid environment.

We show an interaction between the novel cpSRP subunit cpSRP43 and the soluble, stromal-exposed C terminus of Albino3 (Alb3-Cterm). We …

Tryptophan Anchored Peptides In Lipid Bilayer Membranes: Control Of Peptide Orientation And The Phase Behavior Of Cholesterol-Containing Ternary Lipid Mixtures, Johanna Maria Rankenberg

Graduate Theses and Dissertations

Model WALP peptides and "next generation" WALP-derived hydrophobic model peptides were employed to discover principles that govern protein-lipid interactions in biological membranes.

Ternary cholesterol-containing lipid mixtures were examined in the presence of WALP peptides of different lengths (acetyl-GWW(LA)_nLWWA-ethanolamide, with n between 3 and 8). Deuterium NMR spectra from labeled lipids reveal that WALP peptides may stabilize lipid ordered "raft" domains and therefore promote lipid phase separation, albeit to a minor extent. The results depend upon whether dioleolyl- or diphytanoyl-phosphatidylcholine is present as the fluid lipid component.

Several WALP peptides were modified to remove anchoring Trp residues from one …

Stability Of Nucleic Acid Secondary Structures And Their Contribution To Gene Expression, Maged A. Darwish

Seton Hall University Dissertations and Theses (ETDs)

Bacteriorhodopsin (bR) is a highly expressed transmembrane protein that acts as a light-driven proton pump converting light energy into a proton gradient. The extraordinary levels of expression achieved (15-30 mg per liter of culture) are a result of very efficient biogenesis that originates from molecular information encoded in the bacterio-opsin gene {bop) (1). DNA sequence analysis and predictive folding algorithms suggest that the first twenty-five bases of the bop gene mRNA can form a secondary structural element (a "stem-loop"). Using biophysical methods, the goal was to determine if the stem-loop structure exists in solution conditions that mimic the in vivo …

Characterization And Functional Regulation Of Bioactive Peptides In Avian Macrophages And Heterophils, Lakshmi Kannan

Graduate Theses and Dissertations

Oligopeptides and low molecular weight polypeptides play central roles as effectors and signal transducers acting as hormones, neurotransmitters, growth factors, toxins, and antimicrobial factors that are important for the survival of the organism. Owing to the ubiquitous involvement of peptides in many key regulatory processes, we have been interested to identify native peptides in different cells and tissues and understand their functions. To conduct our studies, we used avian macrophages and heterophils as models of specialized cells which constitute central components of innate immunity. These studies involved (a) qualitative identification and characterization of the peptides associated with high intensity mass …

Micro, Nano Encapsulation Methods For Sustained Release Drug Formulations And Biomimetic Applications, Shantanu Balkundi

Doctoral Dissertations

The Layer-by-Layer (LbL) assembly technique was used to obtain a new type of protein/polyphenol microcapsule based on naturally occurring polyphenol (-)-epigallocatechin gallate (EGCG) and gelatin, type A. The dependence of permeability on the molecular weight of permeating substances was studied and compared with commonly used polyallylamine/polystyrene sulfonate capsules. A quartz crystal microbalance was used to monitor the regularities of EGCG adsorption in alternation with type A and B Gelatins and electrophoretic mobility measurements were used that indicated that the nature of assembly was dependent on Gelatin properties. It was shown that EGCG retains its antioxidant activity in the LbL assemblies. …

Gene Synthesis, Cloning, Expression, Purification And Biophysical Characterization Of The C2 Domain Of Human Tensin, Kiran Sukumar Gajula

Doctoral Dissertations

Tensin is a large "docking" protein found in the adhesive junctions of animal cells and recruited early in the development of cell-substrate contacts. There it binds to the cytoplasmic domain of integrin β1 and caps the barbed ends of filamentous actin. This forms a rational basis for its implication in a direct role in the mechanics of membrane-cytoskeleton interactions. Tensin provides a physical link between the actin cytoskeleton, integrins, and other proteins at the cell-substrate contacts. Its overall biochemical properties are a function of its domain composition and architecture, i.e., the domains that are present and their relative positions in …