Sara K Wright

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Tumor cells extensively utilize the pentose phosphate pathway for the synthesis of ribose. Transketolase is a key enzyme in this pathway and has been suggested as a target for inhibition in the treatment of cancer. In a pharmacodynamic study, nude mice with xenografted HCT-116 tumors were dosed with 1 ('N3'-pyridyl thiamine';(More)
Transketolase, a key enzyme in the pentose phosphate pathway, has been suggested as a target for inhibition in the treatment of cancer. Compound 5a ('N3'-pyridyl thiamine'; 3-(6-methyl-2-amino-pyridin-3-ylmethyl)-5-(2-hydroxy-ethyl)-4-methyl-thiazol-3-ium chloride hydrochloride), an analog of the transketolase cofactor thiamine, is a potent transketolase(More)
We performed a fragment screen on the dengue virus serotype 3 RNA-dependent RNA polymerase using x-ray crystallography. A screen of 1,400 fragments in pools of eight identified a single hit that bound in a novel pocket in the protein. This pocket is located in the polymerase palm subdomain and conserved across the four serotypes of dengue virus. The(More)
Several methods for the quantitation of cysteines in proteins have been evaluated and compared. Titration of protein sulfhydryl groups with 5,5'-dithiobis(2-nitrobenzoate) (DTNB) under carefully controlled conditions has extended the detection limits of this method with high accuracy and reproducibility. Results are reported for a variety of enzymes(More)
Malate dehydrogenase from Escherichia coli is highly specific for the oxidation of malate to oxaloacetate. The technique of site-specific modulation has been used to alter the substrate binding site of this enzyme. Introduction of a cysteine in place of the active site binding residue arginine 153 results in a mutant enzyme with diminished catalytic(More)
Inhibition of the thiamine-utilizing enzyme transketolase (TK) has been linked with diminished tumor cell proliferation. Most thiamine antagonists have a permanent positive charge on the B-ring, and it has been suggested that this charge is required for diphosphorylation by thiamine pyrophosphokinase (TPPK) and binding to TK. We sought to make neutral(More)
Kinetic studies and chemical modification studies using diethylpyrocarbonate and iodoacetate were performed on malate dehydrogenase isolated from Escherichia coli. Product inhibition experiments indicate that this enzyme follows an ordered Bi Bi kinetic mechanism, similar to other dehydrogenases, while log V/K profiles reveal that one ionizing group with a(More)
Malate dehydrogenase specifically oxidizes malate to oxaloacetate. The specificity arises from three arginines in the active site pocket that coordinate the carboxyl groups of the substrate and stabilize the newly forming hydroxyl/keto group during catalysis. Here, the role of Arg-153 in distinguishing substrate specificity is examined by the mutant R153C.(More)
The rate-limiting step in the catalysis of the hydration of CO2 by carbonic anhydrase involves transfer of protons between zinc-bound water and solution. This proton transfer can be enhanced by proton shuttle residues within the active-site cavity of the enzyme. We have used chemical modulation to provide novel internal proton transfer groups that enhance(More)
Dengue virus (DENV) is the most significant mosquito-borne viral pathogen in the world and is the cause of dengue fever. The DENV RNA-dependent RNA polymerase (RdRp) is conserved among the four viral serotypes and is an attractive target for antiviral drug development. During initiation of viral RNA synthesis, the polymerase switches from a "closed" to(More)