Molecular Biology Commons^™

Engineering Of Escherichia Coli 2-Oxoglutarate Dehydrogenase Complex With Mechanistic And Synthetic Goals, Joydeep Chakraborty

Dissertations

The Escherichia coli 2-oxoglutarate dehydrogenase complex (OGDHc) compromises multiple copies of three enzymes - 2-oxoglutarate dehydrogenase (E1o), dihydrolipoyl succinyltransferase (E2o), and dihydrolipoyl dehydrogenase (E3). OGDHc is found in the Krebs cycle and catalyzes the formation of the all-important succinyl-Coenzyme A (succinyl-CoA). OGDHc was engineered to understand the catalytic mechanism and optimized for chemical synthetic goals.

Succinyl-CoA formation takes place within the catalytic domain of E2o via a transesterification reaction. The succinyl group from the thiol ester of S8-succinyldihydrolipoyl-E2o is transferred to the thiol group of CoA. Mechanistic studies were designed to investigate enzymatic transthioesterification. His375 and Asp374 was shown to …

Peroxisomal Protein Defects Disrupt Coordinated Peroxisomal Processes And Affect Early Seedling Development Through Accumulating Toxic Catabolic Intermediates, Ying Li

Dissertations

Many peroxisomal proteins act in β-oxidation processes on a range of substrates. It is unclear how these proteins are coordinated to determine the flux of peroxisomal processes and meet the requirements for plant growth and development. Using mutant analysis and metabolic profiling, I examined proteins predicted to act in fatty acid and indole-butyric-acid (IBA) β-oxidation. ECH2 confers enoyl-CoA hydratase activity for the auxiliary β-oxidation of fatty acids with an even cis-unsaturated bond. ECH2 was suggested to function in IBA β-oxidation, as ech2 seedlings have altered IBA response. ech2 seedlings have reduced root length and cotyledon area. ech2 seedlings accumulate 3-hydroxyoctenoate …