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Full-Text Articles in Biology
Investigation Of The Mechanisms Governing Carrier Domain Translocation In S. Aureus Pyruvate Carboxylase, Joshua Hakala
Investigation Of The Mechanisms Governing Carrier Domain Translocation In S. Aureus Pyruvate Carboxylase, Joshua Hakala
Dissertations (1934 -)
A central debate in protein biochemistry focuses on the mechanism by which ligands contribute to conformational changes in proteins. Two primary hypotheses describe this process: the induced-fit hypothesis and the conformational ensembles hypothesis. In contrast to the induced-fit hypothesis, the conformational ensembles hypothesis states that the protein pre-exists in multiple conformational states, with ligand binding shifting the equilibrium towards a preferred conformation. The contribution of ligand binding to large-scale conformational changes is particularly relevant to multi-domain “swinging-arm” enzymes, for which pyruvate carboxylase (PC) serves as a well characterized paradigm system. PC catalyzes the ATP-dependent carboxylation of pyruvate to oxaloacetate. The …
The Discovery And Characterization Of Small Molecule Inhibitors Of Pyruvate Carboxylase, Brittney Wyatt
The Discovery And Characterization Of Small Molecule Inhibitors Of Pyruvate Carboxylase, Brittney Wyatt
Dissertations (1934 -)
Pyruvate carboxylase is a metabolically important enzyme that has been implicated in a wide range of diseases and infections such as cancer, diabetes and listeriosis. Despite the importance of pyruvate carboxylase in these diseases and infections, there are no selective and potent small molecule effectors available to study pyruvate carboxylase both in vitro and in vivo. Effective small molecule effectors of pyruvate carboxylase will expand the biochemical toolkit to facilitate the investigation of the structure, regulation and specific cellular role of pyruvate carboxylase. To discover small molecule effectors of pyruvate carboxylase, a novel fixed time assay was developed. The assay …
A High-Throughput Screening Assay For Pyruvate Carboxylase, Brittney N. Wyatt, Leggy A. Arnold, Martin St. Maurice
A High-Throughput Screening Assay For Pyruvate Carboxylase, Brittney N. Wyatt, Leggy A. Arnold, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Pyruvate carboxylase (PC) catalyzes the conversion of pyruvate to oxaloacetate (OAA), an important metabolic reaction in a wide range of organisms. Small molecules directed against PC would enable detailed studies on the metabolic role of this enzyme and would have the potential to be developed into pharmacological agents. Currently, specific and potentsmall molecule regulators of PC are unavailable. To assist in efforts to find, develop, and characterize small molecule effectors of PC, a novel fixed-time assay has been developed based on the reaction of OAA with the diazonium salt, Fast Violet B (FVB), which produces a colored adduct with …
The Role Of Biotin And Oxamate In The Carboxyltransferase Reaction Of Pyruvate Carboxylase, Adam D. Lietzan, Yi Lin, Martin St. Maurice
The Role Of Biotin And Oxamate In The Carboxyltransferase Reaction Of Pyruvate Carboxylase, Adam D. Lietzan, Yi Lin, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. During catalysis, carboxybiotin is translocated to the carboxyltransferase domain where the carboxyl group is transferred to the acceptor substrate, pyruvate. Many studies on the carboxyltransferase domain of PC have demonstrated an enhanced oxaloacetate decarboxylation activity in the presence of oxamate and it has been shown that oxamate accepts a carboxyl group from carboxybiotin during oxaloacetate decarboxylation. The X-ray crystal structure of the carboxyltransferase domain from Rhizobium etli PC reveals that oxamate is positioned in the active site …
Functionally Diverse Biotin-Dependent Enzymes With Oxaloacetate Decarboxylase Activity, Adam D. Lietzan, Martin St. Maurice
Functionally Diverse Biotin-Dependent Enzymes With Oxaloacetate Decarboxylase Activity, Adam D. Lietzan, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Biotin-dependent enzymes catalyze carboxylation, decarboxylation and transcarboxylation reactions that participate in the primary metabolism of a wide range of organisms. In all cases, the overall reaction proceeds via two half reactions that take place in physically distinct active sites. In the first half-reaction, a carboxyl group is transferred to the 1-N′ of a covalently tethered biotin cofactor. The tethered carboxybiotin intermediate subsequently translocates to a second active site where the carboxyl group is either transferred to an acceptor substrate or, in some bacteria and archaea, is decarboxylated to biotin and CO2 in order to power the export of sodium …
Insights Into The Carboxyltransferase Reaction Of Pyruvate Carboxylase From The Structures Of Bound Product And Intermediate Analogs, Adam D. Lietzan, Martin St. Maurice
Insights Into The Carboxyltransferase Reaction Of Pyruvate Carboxylase From The Structures Of Bound Product And Intermediate Analogs, Adam D. Lietzan, Martin St. Maurice
Biological Sciences Faculty Research and Publications
Pyruvate carboxylase (PC) is a biotin-dependent enzyme that catalyzes the MgATP- and bicarbonate-dependent carboxylation of pyruvate to oxaloacetate, an important anaplerotic reaction in central metabolism. The carboxyltransferase (CT) domain of PC catalyzes the transfer of a carboxyl group from carboxybiotin to the accepting substrate, pyruvate. It has been hypothesized that the reactive enolpyruvate intermediate is stabilized through a bidentate interaction with the metal ion in the CT domain active site. Whereas bidentate ligands are commonly observed in enzymes catalyzing reactions proceeding through an enolpyruvate intermediate, no bidentate interaction has yet been observed in the CT domain of PC. Here, we …
Probing The Allosteric Activation Of Pyruvate Carboxylase Using 2′,3′-O-(2,4,6-Trinitrophenyl) Adenosine 5′-Triphosphate As A Fluorescent Mimic Of The Allosteric Activator Acetyl Coa, Abdussalam Adina-Zada, Rasmani Hazra, Chutima Sereerukb, Sarawut Jitrapakdee, Tonya N. Zeczycki, Martin St. Maurice, W Wallace Cleland, John C. Wallace, Paul V. Attwood
Probing The Allosteric Activation Of Pyruvate Carboxylase Using 2′,3′-O-(2,4,6-Trinitrophenyl) Adenosine 5′-Triphosphate As A Fluorescent Mimic Of The Allosteric Activator Acetyl Coa, Abdussalam Adina-Zada, Rasmani Hazra, Chutima Sereerukb, Sarawut Jitrapakdee, Tonya N. Zeczycki, Martin St. Maurice, W Wallace Cleland, John C. Wallace, Paul V. Attwood
Biological Sciences Faculty Research and Publications
2′,3′-O-(2,4,6-Trinitrophenyl) adenosine 5′-triphosphate (TNP-ATP) is a fluorescent analogue of ATP. MgTNP-ATP was found to be an allosteric activator of pyruvate carboxylase that exhibits competition with acetyl CoA in activating the enzyme. There is no evidence that MgTNP-ATP binds to the MgATP substrate binding site of the enzyme. At concentrations above saturating, MgATP activates bicarbonate-dependent ATP cleavage, but inhibits the overall reaction. The fluorescence of MgTNP-ATP increases by about 2.5-fold upon binding to the enzyme and decreases on addition of saturating acetyl CoA. However, not all the MgTNP-ATP is displaced by acetyl CoA, or with a combination of saturating concentrations of …
Inhibitors Of Pyruvate Carboxylase, Tonya N. Zeczycki, Martin St. Maurice, Paul V. Attwood
Inhibitors Of Pyruvate Carboxylase, Tonya N. Zeczycki, Martin St. Maurice, Paul V. Attwood
Biological Sciences Faculty Research and Publications
This review aims to discuss the varied types of inhibitors of biotin-dependent carboxylases, with an emphasis on the inhibitors of pyruvate carboxylase. Some of these inhibitors are physiologically relevant, in that they provide ways of regulating the cellular activities of the enzymes e.g. aspartate and prohibitin inhibition of pyruvate carboxylase. Most of the inhibitors that will be discussed have been used to probe various aspects of the structure and function of these enzymes. They target particular parts of the structure e.g. avidin – biotin, FTP – ATP binding site, oxamate – pyruvate binding site, phosphonoacetate – binding site of the …