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Physical Sciences and Mathematics Commons

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Chemistry

Old Dominion University

Chemistry & Biochemistry Theses & Dissertations

Theses/Dissertations

2010

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Full-Text Articles in Physical Sciences and Mathematics

Conformational Change And Topological Stability Of Proteins, Jeffrey Andrew Tibbitt Apr 2010

Conformational Change And Topological Stability Of Proteins, Jeffrey Andrew Tibbitt

Chemistry & Biochemistry Theses & Dissertations

The conformation and topology of a protein changes when stabilizing forces are absent, but the mechanisms by which these changes occur remains elusive. This dissertation aims to broaden the understandings. On the conformational level, the M20 loop conformers of E. coli dihydrofolate reductase are interrogated to identify factors responsible for their stability as well as to determine how one conformer might change into another. Molecular dynamics is used to simulate the open, closed and occluded conformers (observed in X-ray crystal structures) under a series of different single ligand conditions. Analysis shows that all open conformers move to a similar new …


Molecular Characterization Of The Soluble Fraction Of Atmospheric Particulate Matter Obtained By Chemical Oxidation With Nitric Acid, Amanda Susan Priest Apr 2010

Molecular Characterization Of The Soluble Fraction Of Atmospheric Particulate Matter Obtained By Chemical Oxidation With Nitric Acid, Amanda Susan Priest

Chemistry & Biochemistry Theses & Dissertations

The availability of information regarding the composition of ambient atmospheric particulate matter and the transformations that these compounds may undergo upon atmospheric transit is surprisingly absent. Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry is used in this study to rapidly evaluate the composition of the water-soluble organic fraction of standard and collected atmospheric particulate matter samples, and the changes that these mixtures undergo upon oxidation with nitric acid. The standard samples include representative particulate matter collected over the course of a year in Washington, D.C. and particulate matter from the exhaust of a diesel-powered engine. The collected sample …