Date of Award

Spring 1-1-2014

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry & Biochemistry

First Advisor

Veronica Vaida

Second Advisor

Joel D. Eaves

Third Advisor

Carol E. Cleland

Fourth Advisor

Veronica M. Bierbaum

Fifth Advisor

Tom R. Cech

Abstract

In this thesis, the unique environment provided by water and its surface is exploited to aid in answering some of the questions surrounding life and its origins. First, the photochemistry of pyruvic acid, a molecule important in modern metabolism and present throughout the modern atmosphere, is explored in the gas phase, atmospheric aerosol particles, and into aqueous solution, illustrating the sensitivity of chemical reactions to environmental conditions. Then, this chemistry is extended to the photochemistry of a single-tailed surfactant of similar chemical functionality, 2-oxooctanoic acid, producing a double-tailed surfactant abiotically followed by spontaneous self-assembly into stable vesicles. This yields a prebiotically plausible synthesis of a primitive enclosure and provides a contribution to the evolution of early membranes in the origin of life.

Further, the water surface is shown to be an advantageous environment for unique chemistry beyond what is available in bulk aqueous solution by selectively concentrating, aligning, and altering the ionization state of useful reactants. In this thesis the ionization state of L-phenylalanine, a natural amino acid, is examined in situ spectroscopically in the surface region, illustrating the change in ionization state at the surface compared with bulk aqueous solution. Further, abiotic peptide bond formation is demonstrated exclusively at the water surface and observed in situ. Condensation reactions such as peptide bond formation are unlikely in bulk aqueous solution on both thermodynamic and kinetic grounds, yet are necessary in many biopolymers essential to modern life. The water surface provides a unique environment for this chemistry.

Finally, mixed surfactant films of differing hydrophobic structure at the water surface are investigated in this thesis. The natural environment is quite complex, stemming from the multifaceted emissions from both biogenic and anthropogenic sources. The specific interactions of water-soluble aromatics (L-phenylalanine, benzoic acid, benzaldehyde) on a stearic acid monolayer film at the air - water interface are studied here relevant to the surfaces of atmospheric aerosol particles and their potential influence on climate. Finally, the same methods are used to explore the interactions of a perturbant (L-phenylalanine) on a model cell membrane (DPPC), contributing to an understanding of the mechanism of disease promoted by the presence of aromatics.

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