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Full-Text Articles in Physical Chemistry

Saponin Penetration And Interactions With Membranes, Sarai Guerrero Nov 2019

Saponin Penetration And Interactions With Membranes, Sarai Guerrero

Electronic Thesis and Dissertation Repository

The saponin QS21 has been used and studied for years as an adjuvant agent to improve vaccines for both humans and animals. However, how the saponin interacts with the membrane and itself remains poorly understood. We studied the QS21-A majority isomer using all-atom classical molecular dynamics simulations in model bilayers composed of cholesterol and either DOPC or DPPC. As this is one of the few computational studies on QS21-A, we had very few resources to compare our results to. Nevertheless, we were able to gain insight into possible configurations that QS21-A takes after penetration, the effect of the bilayer on …


Using Molecular Dynamics To Study Qs21 Interactions And Penetration Of Lipid-Cholesterol Bilayers, Sarai Guerrero, Mikko Karttunen Jun 2019

Using Molecular Dynamics To Study Qs21 Interactions And Penetration Of Lipid-Cholesterol Bilayers, Sarai Guerrero, Mikko Karttunen

Western Research Forum

Saponins have been used as adjuvant agents for decades in vaccines and therapies, but none are as well studied or heavily used as QS-21. This achievement is notwithstanding the fact that QS-21 usage is limited by its stability, toxicity, and scarcity. These shortcomings have only pushed researchers to develop and experiment with artificial recreations of the saponin to harness its unique benefits. A considerable number of research hours have been poured into this topic, but like QS-21 there is a shortcoming here as well. The number of articles that look at QS-21 interactions with the bilayer or the conditions under …


Crystal Structure Of Zymonic Acid And A Redetermination Of Its Precursor, Pyruvic Acid, Dominik Heger, Alexis J. Eugene, Sean R. Parkin, Marcelo I. Guzman Jun 2019

Crystal Structure Of Zymonic Acid And A Redetermination Of Its Precursor, Pyruvic Acid, Dominik Heger, Alexis J. Eugene, Sean R. Parkin, Marcelo I. Guzman

Chemistry Faculty Publications

The structure of zymonic acid (systematic name: 4-hy­droxy-2-methyl-5-oxo-2,5-di­hydro­furan-2-carb­oxy­lic acid), C6H6O5, which had previously eluded crystallographic determination, is presented here for the first time. It forms by intra­molecular condensation of parapyruvic acid, which is the product of aldol condensation of pyruvic acid. A redetermination of the crystal structure of pyruvic acid (systematic name: 2-oxo­propanoic acid), C3H4O3, at low temperature (90 K) and with increased precision, is also presented [for the previous structure, see: Harata et al. (1977). Acta Cryst. B33, 210–212]. In zymonic acid, the hy­droxy­lactone ring …


Mechanistic Studies And Derivative Effects In 1, 3, 4- Oxadiazole Synthesis Via Cyclodehydration Reactions, Evan Huggins Apr 2019

Mechanistic Studies And Derivative Effects In 1, 3, 4- Oxadiazole Synthesis Via Cyclodehydration Reactions, Evan Huggins

Undergraduate Honors Thesis Projects

In the world of pharmaceutical synthesis, research to combat foreign pathogens is always necessary. Scientists have been exploring different methods in order to synthesize the most effective compounds in antibacterial, anticancer, anti-inflammatory, and many other treatments. A key component within these versatile compounds are 1,3,4-oxadiazoles. Current methods to synthesize these compounds are inefficient. This research seeks to improve oxadiazole synthesis; however, the mechanism of this reaction is unknown. The goal of this project was to study the mechanistic pathway in the discovered, one-pot cyclodehydration synthesis of 1,3,4-oxadiazoles. In the first part of this study, a diacylhydrazine intermediate was proposed. This …


I3: Isomerization Of Isomer Ions, Krisztián Gabor Torma Jan 2019

I3: Isomerization Of Isomer Ions, Krisztián Gabor Torma

University of the Pacific Theses and Dissertations

Photoelectron Photoion Coincidence (PEPICO) spectroscopy is a robust tool for elucidating complex unimolecular dissociation mechanisms and for determining thermochemical and kinetic data of gas-phase ion dissociations with high accuracy. In this work, the dissociative photoionization of two sets of isomeric systems were analyzed with PEPICO: 1) C7H7+ ions of toluene (Tol) and 1,3,5-cycloheptatriene (CHT), and 2) two butyl alcohol isomers, 1-butanol and isobutanol. Threshold dissociative photoionization data on these four molecules of interest were collected on the imaging PEPICO apparatus at the VUV beamline of the Swiss Light Source. Data analysis was aided by ab initio calculations and Rice-Ramsperger-Kassel-Marcus (RRKM) …


The Impact Of Post Translational Modification On The Aggregation Of The Ss-Amyloid Peptide In The Presence Or Absence Of Lipids, Albert Walton Pilkington Iv Jan 2019

The Impact Of Post Translational Modification On The Aggregation Of The Ss-Amyloid Peptide In The Presence Or Absence Of Lipids, Albert Walton Pilkington Iv

Graduate Theses, Dissertations, and Problem Reports

Alzheimer’s disease (AD) is a neurodegenerative condition afflicting 5.7 million Americans with no effective treatments. The pathology of AD is described by the formation of neurotoxic oligomers formed by the self-assembly of amyloid-β (Aβ). The affinity of oligomers for cellular membranes disrupts calcium homeostasis and is believed to be the underlying cause of neurotoxicity; however, due to the metastability of oligomers, it has been difficult to understand their role in membrane interactions and self-assembly. Here we utilize post translational modifications (PTM) to understand the role of specific amino acids on Aβ40-membrane interactions and self-assembly. We employ ThT, AFM, …