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Marquette University

Articles 1 - 8 of 8

Full-Text Articles in Biochemistry

Allosteric Regulation Of Pyruvate Carboxylase, Yumeng Liu Oct 2018

Allosteric Regulation Of Pyruvate Carboxylase, Yumeng Liu

Dissertations (1934 -)

Pyruvate carboxylase (PC; E.C.6.4.1.1) is a multifunctional, biotin-dependent enzyme that catalyzes the MgATP-dependent carboxylation of pyruvate to oxaloacetate. The overall reaction is accomplished by the coupling of two half reactions occurring at two spatially distinct catalytic domains by the translocation of a carrier domain, resulting in a net transfer of CO2 from bicarbonate to pyruvate. PC activity is regulated by multiple allosteric effectors with acetyl CoA serving as an activator in most species and L-aspartate serving as an inhibitor for microbial PC. The kinetic characterization of PC from different species have revealed that PC homologs are subject to divergent degrees …

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Dynamics And Interactions Of Membrane Proteins, Azamat Galiakhmetov Jul 2018

Dynamics And Interactions Of Membrane Proteins, Azamat Galiakhmetov

Dissertations (1934 -)

Membrane proteins are members of the class of proteins that perform their functions while being associated with a lipid bilayer. In the cell, they serve as transporters, receptors, anchors and enzymes. The domain organisation of these proteins suggests importance of lipid membrane and protein-lipid interactions for protein function. The requirement of a membrane mimic and the level of its resemblance to a native one for protein investigation makes the studies of membrane proteins a challenging project. My research work is focusing on the biophysical and biochemical studies of membrane proteins. This dissertation outlines two separate projects, each with their own …

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Strategies For The Modulation Of Protease Activated Receptors (Pars), Disha M. Gandhi Jul 2018

Strategies For The Modulation Of Protease Activated Receptors (Pars), Disha M. Gandhi

Dissertations (1934 -)

Protease-activated receptors (PARs) are class A G protein-coupled receptors (GPCRs) with 4 subtypes (PAR 1 – 4) and with a unique mode of action. PARs are cleaved by extracellular proteases at the N-terminus, creating a new tethered ligand that activates the receptor and transduces biological signals into the cell. PARs have been implicated in various productive and pathological signals, including those related to thrombosis, inflammation, reperfusion injury, and cancer cell metastasis. Despite the fact that PARs are attractive as drug targets, their intramolecular mode of activation makes it challenging to modulate them with drugs in a selective manner, and only …

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Characterization Of The Rcf1 Q-X3-R-X-R-X3-Q Motif And Its Role In Supporting Oxidative Phosphorylation Enzyme Complexes, Joshua Garlich Oct 2016

Characterization Of The Rcf1 Q-X3-R-X-R-X3-Q Motif And Its Role In Supporting Oxidative Phosphorylation Enzyme Complexes, Joshua Garlich

Dissertations (1934 -)

Mitochondrial respiratory complexes are critical components of cellular energy production that require tight regulation to ensure optimal function. Rcf1 and Rcf2 are mitochondrial proteins that can physically associate with the yeast respiratory complexes III and IV, and the higher-ordered III-IV respiratory supercomplex that also contains the ADP/ATP translocase, AAC. Rcf1 can physically associate with both complex III and IV independently, and can be chemically crosslinked to AAC, indicating a close physical proximity to a predominant regulator of energy flux within the cell. It was therefore hypothesized that Rcf1, through its physical association with complexes III and IV, and its close …

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Ligand Frameworks For Transition-Metal Complexes That Model Metalloenzyme Active, Denan Wang Oct 2015

Ligand Frameworks For Transition-Metal Complexes That Model Metalloenzyme Active, Denan Wang

Dissertations (1934 -)

Advances in the field of biomimetic inorganic chemistry require the design of sophisticated ligand frameworks that reflect the amazing complexity of metalloenzyme active sites. For instance, most active sites feature extensive hydrogen-bonding interactions between ligands bound to the metal center (the “first” coordination sphere) and nearby units in the outer (or “second”) sphere. Since these interactions modify the structural and electronic properties of the active sites, a number of inorganic chemists have sought to design ligands that permit outer-sphere functional groups to interact with first-sphere donors. This dissertation describes our contribution to these broader efforts to model the second coordination …

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Structural And Biochemical Studies Of The Carboxyltransferase Domain From Pyruvate Carboxylase, Adam David Lietzan Oct 2014

Structural And Biochemical Studies Of The Carboxyltransferase Domain From Pyruvate Carboxylase, Adam David Lietzan

Dissertations (1934 -)

Pyruvate carboxylase (PC; E.C. 6.4.1.1), a multifunctional biotin-dependent enzyme, catalyzes the bicarbonate- and MgATP-dependent carboxylation of pyruvate to oxaloacetate. To complete the overall reaction, the tethered biotin prosthetic group must first gain access to the biotin carboxylase domain and become carboxylated, and then translocate to the carboxyltransferase (CT) domain where the carboxyl group is transferred from biotin to pyruvate. Kinetic analyses of PC have suggested that the spatially distinct reactions, which occur in the active sites of the BC and CT domains, are well coordinated. To gain insights into the molecular events necessary for coordinating catalysis in the CT domain, …

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Resonant Two-Photon Ionization Studies Of Non Covalent Interactions In Halo Aromatic Clusters And Spin-Orbit Coupling Modeling In Mono-Halocarbenes, Silver Nyambo Oct 2014

Resonant Two-Photon Ionization Studies Of Non Covalent Interactions In Halo Aromatic Clusters And Spin-Orbit Coupling Modeling In Mono-Halocarbenes, Silver Nyambo

Dissertations (1934 -)

Non-covalent interactions in halobenzenes (PhX) (X=F, Cl, Br) and phenylamine (C6 H5 NH2 ) have been studied here using resonance two-photon ionization (R2PI) spectroscopy combined with a linear TOF-mass spectrometer. Their interaction with polar molecules in form of ammonia (NH 3 ) and trifluorohalomethanes (CF3 X) has also been studied. DFT and TD-DFT calculations using M06-2X functionals were carried out on different cluster conformations to compliment experimental results. A general trend of broadness in homogenous dimers (PhX)2 , has been attributed to mainly the presence of multiple cluster isomers and Frank-Condon activity in the low …

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Spectroscopic Studies On Arabidopsis Ethe1, A Glyoxalase Ii-Like Protein, Meghan M. Holdorf, Brian Bennett, Michael W. Crowder, Christopher A. Makaroff Sep 2008

Spectroscopic Studies On Arabidopsis Ethe1, A Glyoxalase Ii-Like Protein, Meghan M. Holdorf, Brian Bennett, Michael W. Crowder, Christopher A. Makaroff

Physics Faculty Research and Publications

ETHE1 (ethylmalonic encephalopathy protein 1) is a β-lactamase fold-containing protein that is essential for the survival of a range of organisms. In spite of the apparent importance of this enzyme, very little is known about its function or biochemical properties. In this study Arabidopsis ETHE1 was over-expressed and purified and shown to bind tightly to 1.2 ± 0.2 equivalents of iron. 1H NMR and EPR studies demonstrate that the predominant oxidation state of Fe in ETHE1 is Fe(II), and NMR studies confirm that two histidines are bound to Fe(II). EPR studies show that there is no antiferromagnetically coupled Fe(III)Fe(II) …

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