Chairperson, Graduate Committee: Jennifer DuBoisMattice, Jenna RoseThesis includes a paper of which Jenna R. Mattice is not the main author.2019-08-302019-08-302019https://scholarworks.montana.edu/handle/1/15546Atmospheric carbon dioxide (CO 2) is used as a carbon source for building biomass in plants and most engineered synthetic microbes. Ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO), the most abundant enzyme on earth, is used by these organisms to catalyze the first step in CO 2 fixation. 1,2 Microbial processes that also fix carbon dioxide or bicarbonate have more recently been discovered. My research focuses on a reaction catalyzed by 2-KPCC (NADPH:2-ketopropyl-coenzyme M oxidorectuase/ carboxylase), a bacterial enzyme that is part of the flavin and cysteine-disulfide containing oxidoreductase family (DSORs) which are best known for reducing metallic or disulfide substrates. 2-KPCC is unique because it breaks a comparatively strong C-S bond, leading to the generation of a reactive enolacetone intermediate which can directly attack and fix CO 2. 2-KPCC contains a phenylalanine in the place where most other DSOR members have a catalytically essential histidine. This research focuses on studying the unique reactive form of 2-KPCC in presence of an active site phenylalanine.enCarbon dioxideOxidoreductasesEnzymesCatalystsCarbonSulfurThesisCopyright 2019 by Jenna Rose Mattice