Biochemistry Commons^™

Interactions In The Cpsrp Dependent Targeting Of Light Harvesting Chlorophyll Binding Protein To The Thylakoid Membrane, Rory Henderson

Graduate Theses and Dissertations

Targeting of proteins is a critical component of cellular function. A universally conserved targeting system of the cytosol utilizes a signal recognition particle (SRP) to target many proteins contranslationally to the endoplasmic reticulum in eukaryotes or the inner membrane in prokaryotes. A homologous SRP system exists in the chloroplast that delivers light harvesting chlorophyll binding proteins (LHCP) to they thylakoid membrane. The chloroplast SRP (cpSRP) is a heterodimer composed of a novel 43 kDa subunit and a 54 kDa subunit homologous to a component of the SRP system, SRP54. Many details regarding the interactions between the proteins of the cpSRP …

Engineered Human Acidic Fibroblast Growth Factor (Fgf1) With An Enhanced Thermal And Proteolytic Stability, Duaa Abdullah Almansaf

Graduate Theses and Dissertations

Fibroblast growth factor receptor (FGFR) is made up of three significant domains. The most important domain is the intracellular domain where the dimerization and autophosphorylation occur. Fibroblast growth factor (FGF) interacts with specific FGFR to regulate many cellular processes during the embryonic stage. Furthermore, FGF is significant for adults because FGF plays an important role in regulating cellular differentiation as well as wound healing. The cellular regulating processes are initiated through binding FGF to heparin followed by binding FGF/heparin to FGFR to form FGF/heparin/FGFR complex. Thus, FGFR is dimerized and autophosphorylated. The phosphorylation of FGFR triggers downstream signaling pathways, which …

Influence Of Ph And Acidic Side Chain Charges On The Behavior Of Designed Model Peptides In Lipid Bilayer Membranes, Venkatesan Rajagopalan

Graduate Theses and Dissertations

The molecular properties of transmembrane proteins and their interactions with lipids regulate biological function. Of particular interest are interfacial aromatic residues and charged residues in the core helix whose functions range from stabilizing the native structure to regulating ion channels. This dissertation addresses the pH dependence and influence of potentially negatively charged tyrosine, glutamic acid or aspartic acid side chains. We have employed GWALP23 (acetyl-GGALW5LALALALALALALW19LAGA-amide) as favorable host peptide framework. We have substituted W5 with Tyr (Y5GWALP23) and Leu residues with Glu (L12E, L14E or L16E) or Asp (L14D or L16D), and have incorporated specific 2H-labeled alanine residues within the …

Membrane Chromatography For Bioseparations: Ligand Design And Optimization, Zizhao Liu

Graduate Theses and Dissertations

Membrane chromatography, or membrane adsorber, represents an attractive alternative to conventional packed bed chromatography used in downstream processing. Membrane chromatography has many advantages, including high productivity, low buffer consumption and ease to scale up. This doctoral dissertation focuses on developing novel polymeric ligands for protein separations using membrane chromatography. Atom transfer radical polymerization (ATRP), known as a controlled radical polymerization technique, has been used to control the architecture of grafted polymeric ligands. The center theme of this dissertation is to develop new polymeric ligands and investigate how the polymer’s property (e.g. flexibility, hydrophobicity) and architecture (e.g. chain density, chain length) …

Bioorthogonal Reactions: Synthesis And Evaluation Of Different Ligands In Copper Catalyzed Azide-Alkyne1,3-Dipolar Cycloaddition (Cuaac), Zainab Abdullah Almansaf

Graduate Theses and Dissertations

The Copper CatalyzedAzide-Alkyne1,3-Dipolar Cycloaddition (CuAAC) reaction has unique features that qualify it to be one of the best click reactions. Its applications have been shown in different aspects and for multiple purposes. The oxidative degradation of biological systems (labile proteins and live cells) is, however, generally recognized as the major problem when using this reaction in living systems. Reactive oxidation species can be easily produced in the presence of copper(II), ascorbate and air, and this is the main cause of toxicity. However, the uses of ligands have shown a major impact on reducing copper toxicity, protecting Cu(I) from the redox …

Heparin-Peptide Interactions, Jacqueline Anastasia Morris

Graduate Theses and Dissertations

Heparin is a polydispersed sulfated molecule that is part of the family called glycosaminoglycans found in the extracellular matrix and cell surfaces. This molecule is extremely important for the activation of proteins and protein-receptor interactions that are responsible for downstream cell signaling pathways. Heparin has been isolated from porcine intestine and used as an anticoagulant for the prevention of embolisms, heart thrombosis, and clotting during heart surgeries. This so-called miracle drug was in use until 2008, when isolated batches were found to be contaminated with other glycosaminoglycans similar to heparin. From 2008, there has been a dire need for a …

Applications Of The Gst- Affinity Tag In The Purification And Characterization Of Proteins, Wibke Beatrice Kachel

Graduate Theses and Dissertations

With the latest innovations in biological sciences, large quantities of biologically active polypeptides as well as high throughput screening methods to quickly evaluate if these biomolecules potentially have therapeutic, diagnostic, or industrial purposes are required. The synthesis and purification of peptides and small proteins continue to be demanding as the production of high yields through chemical synthesis can involve large costs. On the other hand, there are only few examples of acquiring those biomolecules through cloning and expression in bacterial systems in form of recombinant fusion proteins. Glutathione S-Transferase (GST) is not only a very commonly used affinity tag to …

Investigation Of The Interaction Of Dimeric Ruthenium Complexes With Cytochrome B5, Christopher Dain Rupar

Graduate Theses and Dissertations

Photoreactive complexes to study the kinetics of electron transfer of proteins have been in use for a long time. It has always been speculated that complexes bind near the heme or the electron transfer reaction would not occur. But it is unkown exactly how the complex interacts with the protein. The structural, thermodynamic, and kinetic properties of rat liver microsomal cytochrome b5 were investigated when bound to ruthenium dimer complexes. Heteronuclear Single Quantum Coherence studies support a dynamic binding model of a dimer Ru complex bound near the protein’s heme involving residues H39, E44, G42, V61, G62, and H63. The …

Two-Electron Quenching Of Dinuclear Ruthenium(Ii) Polypyridyl Complexes, Yinling Zhang

Graduate Theses and Dissertations

A bridging ligand 5,5’-Bi- 1,10-phenanthroline, diphen, was prepared using dichlorobis(triphenylphosphine)Ni(II), Ni(PPh3)2Cl2 as catalyst with a yield of 40%. Yellow cubic crystals were able to obtain from the good purity product for single crystal analysis. The torsion angle between the planes of the subunit phenanthrolines is about 66 degrees.

A dinuclear ruthenium (II) polypyridyl complex, (phen)2Ru(diphen)Ru(phen)24+, was synthesized by using polymeric ruthenium carbonyl compound as the entry point, diphen as the bridging ligand and 1,10-phenanthroline, phen, as the terminal legand. Brown needlelike crystals were precipitated from acetonitrile that were not suitable for single crystal diffraction.

The photochemistry of the dimer was …

Mechanism Of Rapid Electron Transfer Reactions Involving Cytochrome Bc1, Cytochrome C And Cytochrome Oxidase, Jeremy Erik Durchman

Graduate Theses and Dissertations

Electron transfer between mitochondrial proteins complexes represents the primary means by which living things acquire the requisite energy for survival. The coupling of electron transfer to proton translocation creates an electrochemical gradient that drives the synthesis of highly energetic compounds such as ATP. The purpose of these studies is to measure rates of electron transfer and elucidate the important governing factors in the redox events involving cytochrome bc1, cytochrome c and cytochrome oxidase. Using rapid initiation of redox events triggered by laser flash excitation of ruthenium compounds, and strategically monitoring unique spectral properties of these proteins in the visible region …