Biochemistry 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 …

Enhancing Nanopore Based Biosensening Technology Using Pore Forming Proteins, Christina M. Chisholm

Doctoral Dissertations

Pore forming proteins (PFPs) are membrane channels that are essential for various biological processes. For example, some PFPs act as gatekeepers of the cell, controlling the traffic of ions and macromolecules flowing into and out of cells; while others are involved in causing cell death (Reiner et al., 2012). Our fundamental understanding of PFPs determines our ability to employ these proteins for use in biomedical research and nanopore technology. Given their nanoscale dimensions, reproducibility and functionality these PFPs are widely used in the growing field of nanopore technology, particularly nanopore sensing (Reiner et al., 2012; Feng et al., 2015). These …

Impact Of Conformational Change, Solvation Environment, And Post-Translational Modification On Desulfurization Enzyme 2'-Hydroxybiphenyl-2-Sulfinate Desulfinase (Dszb) Stability And Activity, Landon C. Mills

Theses and Dissertations--Chemical and Materials Engineering

Naturally occurring enzymatic pathways enable highly specific, rapid thiophenic sulfur cleavage occurring at ambient temperature and pressure, which may be harnessed for the desulfurization of petroleum-based fuel. One pathway found in bacteria is a four-step catabolic pathway (the 4S pathway) converting dibenzothiophene (DBT), a common crude oil contaminant, into 2-hydroxybiphenyl (HBP) without disrupting the carbon-carbon bonds. 2’-Hydroxybiphenyl-2-sulfinate desulfinase (DszB), the rate-limiting enzyme in the enzyme cascade, is capable of selectively cleaving carbon-sulfur bonds. Accordingly, understanding the molecular mechanisms of DszB activity may enable development of the cascade as industrial biotechnology. Based on crystallographic evidence, we hypothesized that DszB …

Inteins From Pathogenic Microbes As Regulatory Elements And Potential Drug Targets, Cathleen Maria Schiraldi

Legacy Theses & Dissertations (2009 - 2024)

Inteins are self-splicing elements that orchestrate the autocatalytic process of protein splicing, during which the intein excises itself from a host polypeptide. This multistep reaction involves a series of coordinated nucleophilic attacks and peptide bond rearrangements that remove the intein and reassemble the flanking halves, called exteins, to form the mature host protein. Some inteins are also mobile elements, and can spread to the same or ectopic sites using an internal homing endonuclease domain.