Summer Research 2014

Summer research 2014

Celebration of Summer Research September 11, 2014

Abstracts of chemistry student poster presentations

 

The Role of Tau Protein Oligomerization in Neurodegenerative Disease

Tau protein is an essential microtubule-associated protein that provides support to the nervous system. In some cases, the natively unfolded tau forms abnormal fibrillar deposits in the brain and causes neurodegenerative disease. Recent research suggests that oligomers of tau may be more toxic than fibrils. A 39-mer fragment was chosen to investigate the oligomerization potential in a region of tau. The peptide was synthesized by solid phase peptide synthesis. Mass spectral data revealed a significant amount of oxidized product. The reduction and purification of the peptide will be discussed. The purified peptide has been studied using electron microscopy and circular dichroism. Nicolette Dressler '15 and Kristi Lazar Cantrell, Assistant Professor of Chemistry.

EW-CRDS and the Spatial Investigation of Adsorption on a Fused Silica Prism

Phosphotungstic acid (PW12O40) has been shown to improve the rate of proton transfer in polymer electrolyte membrane fuel cells. The interactions between (3-aminopropyl)-trimethoxysilane (APTMS) and phosphotungstic acid (PTA) were studied on a fused-silica prism through the use of evanescent-wave cavity-ringdown spectroscopy (EW-CRDS). It was discovered that PTA will adsorb irreversibly to higher concentration of APTMS. The adsorption of PTA to APTMS showed a ΔG°of adsorption -81 kJ/mole ±17, indicating PTA adsorption to APTMS is favorable under standard state conditions. Jordan Kohl, Christopher Sue, and Michael Everest, Professor of Chemistry

Formation of β-sheet fibrilsfromoctapeptidemixtures

The association ofβ-sheets has been implicated in the formation of protein aggregates and fibrils observed in many human diseases, including Alzheimer’s disease and Huntington’s disease.The followingoctapeptideswere synthesized by manual solid phase peptide synthesis to investigate whether engineering electrostatic and hydrophobic interactions in the peptides inducesβ-sheet amyloid fibril formation: (1) Ac-EFFKFFEY-NH2, (2) Ac-KFFEFFKY-NH2, (3) Ac-KFFKFFKY-NH2, and (4) Ac-EFFEFFEY-NH2.The peptides were purified using High Pressure Liquid Chromatography (HPLC) and the masses were confirmed using mass spectrometry. The propensity of Peptides 1-4 to form fibrils was investigated by incubating the individual peptides and peptide mixtures. Fibril formation was tested byThioflavinT fluorescence, circulardichroismandelectron microscopy.Benjamin Trapp '15, Tjitske Veldstra '14, Dean LaBarba '13 and Kristi Lazar Cantrell, Assistant Professor of Chemistry

Effect of 1-Chloropentane on the Fluorescence from a Mixture of Naphthalene and 2-Ethylnaphthalene on Alumina

Bilayers of 1-chloropentane and a mixture of naphthalene and 2-ethylnaphthalene were formed by vapor deposition onto a single crystal of α-alumina. The fluorescence was monitored as the surface temperature of the α-alumina was linearly ramped in a temperature programmed desorption experiment. The effect of 1-chloropentane during the temperature programmed desorption experiment was the formation of monomers of 2-ethylnaphthalene with the mixture of 2-ethylnaphthalene and naphthalene. It also caused the mixture to undergo more structured, irreversible structural relaxation within the adlayer. During the temperature programmed desorption, naphthalene solvated and donated its energy to 2-ethylnaphthalene.  Melissa Shew ’16, Rachel DeHoog15, Ken Martin (Professor of Chemistry, Pt. Loma Nazarene University), Allan Nishimura, Emeritus Professor of Chemistry.

Separation and photoactivity studies of Ru-dendrimer nano particles

This project seeks to develop and study dendrimer nanoparticles bound to Ru-ligands capable of photoactively reducing ionic pollutants and eliminating them from contaminated water sources. Past work has focused on coupling the [Ru(bpy)2(dcbpy)]2+ to G2.0 PAMAM dendrimers and studying their reductive capabilities. While quenching studies have shown the complex is capable of increasing reduction rate, it is unknown how the ratio of Ru: dendrimer affect the frequency of electron transfer. Therefore, current work has concentrated on separating distinct ratios with ion-exhange chromatography with FPLC and purifying samples so these photoactive properties can be analyzed. Previously fractionated material has already undergone quantum yield studies, showing there is a slightly reduced quantum yield as the the Ru:dendrimer ratio increases. Quantum yield pH studies on individual fractions demonstrate a factor of 2 increase from pH 2 and 4 due to the deprotonation of Ru-ligand carboxy groups. Elizabeth P Simoneit and Stephen M. Contakes, Assistant Professor of Chemistry

Generation of Novel Plasmids and Recombinant Protein for Use in DNA Vaccination against HSV-1.

The production of a successful DNA vaccine has eluded researchers for many years. Using Herpes Simplex Virus-1 (HSV-1) glycoprotein B (HSVgB) as a model antigen, we hypothesize that vectors encoding HSVgB and Pattern Recognition Receptor (PRR) and CD40 agonist adjuvants can be used to yield an efficacious DNA vaccine. Here we document the generation of plasmids to be used in DNA vaccination against HSV-1, the production of recombinant HSVgB, and testing of this DNA vaccine. Cloning by lambda-phage recombineering and traditional restriction digestion and ligation was used to generate plasmids encoding antigen HSVgB and adjuvants FGK45 and flagellin. Transfection of HEK293T cells and subsequent analysis by ELISA confirmed the production of these recombinant proteins in vitro. Initial murine studies suggest that injection with these vectors induces CD8 T-cell proliferation indicative of a pathogen-specific response. Collectively, our data represent promising developments in DNA vaccinology. A.J. Wilk 1,2,3, E.C. Cross 2,3, A.L. Ortiz 2,3, N.D. Pennoc 2,3,  A.C. Chitrakar 2 , and R.M. Kedl 2.

1.Department of Biology, Westmont College, Santa Barbara, CA 93108.2. Department of Immunology and Microbiology, University of Colorado School of Medicine, Aurora, CO 80045.3. National Jewish Health, Denver, CO 80206.

Synthesis and Structural Characterization of (N-ferrocenyl isonicotinamide) N,N′-Bis(salicylidene)ethylenediaminocobalt(II), a Co(salen) Complex with Redox Active Pyridyl Axial Ligand

This project aims to develop a synthetic catalyst to facilitate the monooxygenation of hydrocarbons. Co(salen) is known to bind oxygen and the hope is that when Co(salen) is modified by redox active axial ligands it can be used to mimic the heme porphyrin active site of Cytochrome P450. Cytochrome P450 is a liver detoxification enzyme that is known to perform monooxygenation reactions in the body. The hope is that by attaching redox active ligands to the planar Co(salen ) compound the ligands will be able to donate single electrons thus turning the Co(salen) compound from purely an oxygen storage compound to an oxygen reduction compound. A ferrocenyl Isonicotinamide ligand was attached axially to Co(salen) and elemental analysis confirmed the purity of crystals grown from the synthesis. A second ligand, [Ru(bpy)2(5-py-CONH-phenanthroline)][PF6]2 , was purified and characterized by NMR and a crystal growth experiment was prepared. Ellen Brudi ‘15, Stephen M. Contakes, Assistant Professor of Chemistry