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Full-Text Articles in Physical Sciences and Mathematics
Photofragment Imaging Fast Ion Beams, Michael D. Johnston Jr.
Photofragment Imaging Fast Ion Beams, Michael D. Johnston Jr.
Doctoral Dissertations
Metal-containing ions have been the subject of much research due to their roles in catalytic activation and small cluster chemistries. However, they can be difficult to study both experimentally and theoretically, and new approaches are needed. The goal of the research described here is to characterize the electronic structures and thermodynamics of metal-containing ions using gas-phase spectroscopy experiments performed on a powerful new instrument. Presented in the following chapters are the details of a recently built velocity map imaging mass spectrometer that is capable of imaging the photofragments of trap-cooled (≥7K) ions produced in a versatile ion source. This instrument …
Spectroscopic Insight Into Oxidative Heme Cleavage By The Non-Canonical Heme Oxygenase Isdg From Staphylococcus Aureus, Matthew A. Conger
Spectroscopic Insight Into Oxidative Heme Cleavage By The Non-Canonical Heme Oxygenase Isdg From Staphylococcus Aureus, Matthew A. Conger
Graduate College Dissertations and Theses
IsdG and IsdI are non-canonical heme oxygenases (HO) from Staphylococcus aureus that catalyze the oxidative cleavage of heme to give novel organic products (staphylobilins) and iron as a nutrient for the pathogen. Comparison of the reported equilibrium dissociation constant (Kd) values for heme from IsdG and IsdI compared to the reported concentration of the labile heme pool called into question whether these enzymes are competent HOs in vivo. We took advantage of a second-sphere Trp whose fluorescence is quenched upon heme binding, which led to Kd values 2-3 orders of magnitude smaller than reported in the literature. Importantly, these Kd …