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Showing 1 to 19 of 19 for “"pterin"”.
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Bacterial Cyanide Assimilation: Pterin Cofactor and Enzymatic Requirements for Substrate Oxidation
… oxygenase (CNO), which exhibits properties of a pterin-dependent hydroxylase. The pterin requirement for Pf11764 CNO was satisfied by supplying either the fully (tetrahydro) or partially (dihydro) reduced forms of various pterin compounds at catalytic concentrations (0.5 µM). These compounds …
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The Indivisible System: Modeling The Metal-Pterin-Dithiolene System In Molybdenum And Tungsten Cofactors
… of functionality in these enzymes, the pyranopterin-dithiolene (PDT) ligand. A total of eight possible electron redox equivalents occurs between the metal center and PDT, making the molybdenum cofactor (Moco) and the tungsten cofactor (Tuco) the most redox rich cofactors in all of biology. …
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Metabolic engineering of the pterin branch of folate synthesis by over-expression of a GTP cyclohydrolase I in peanut
Folate, also known as vitamin B9, is an essential dietary vitamin that provides the donor group for one carbon transfer reactions. Deficiency in folate is associated with neural tube birth defects (NTDs), cancer, cardiovascular disease, and anemia. In the US enriched food products including bread, …
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Isolation and characterization of new pterins from nonmethanogenic archaebacteria
Several new pterins have been discovered in halophilic and thermoacidophilic archaebacteria. Two of these were identified in the extreme halophiles and were thus called halopterins. One of these halopterins is produced by Halobacterium salinarium, Halobacterium halobium, and Halococcus morrhuae and …
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The Molybdenum Cofactor: Modeling the Swiss Army Knife of Metabolic Diversity
<p>The pterin-dithiolene ligand (MPT), uniquely found in mononuclear molybdenum (Mo) and tungsten (W) enzymes, continues to intrigue us. The complexity of this ligand has been suggested as a cog in Mo and W enzyme function, and the pterin has been increasingly appreciated for its electronic …
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Structural and Kinetics Studies of the Enzyme Dihydropteroate Synthase and the Implications for Antibiotic Resistance
… (<em>p</em>ABA) and 6-hydroxymethyl-7,8-dihydropterin-pyrophosphate (DHPPP), which bind to separate and distinct regions of the protein. Sulfonamides act by binding the <em>p</em>ABA pocket composed largely of dynamic loop regions which fold in upon substrate binding to complete the active site. …
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Structure based design of a ricin antidote
… the most promising leads belonging to the pterin family. To date, the most potent RTA inhibitors developed using this approach are only modest inhibitors with apparent IC50 values in the 10-4 M range, leaving significant room for improvement. This thesis discusses the development of a …
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The role of molybdenum in the formate dehydrogenase of methanobacterium formicicum
An examination of oxidation products of the pterin cofactor in the formate dehydrogenase of Methanobacterium formicicum revealed that the cofactor is a 6-substituted pterin similar to the molybdopterin of xanthine oxidase. In contrast to the molybdopterin from xanthine oxidase the formate …
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The maintenance of variation in Cyprinodontiformes
… pigment. Color in the anal fin was either pterin based (yellow and red) or structural (blue) with a melanic fin border. Using a behavioral assay designed to measure dominance, I sought to determine the informational content of each pigment. Black melanic markings on the anal fin were …
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Tetrahydrobiopterin Metabolism in Mental Retardation
… and minimal detection limits of various pterins under fixed conditions was noted. The stability of pterins under different oxidation conditions was investigated. Acid- and alkaline-oxidation of reduced biopterins produced almost stoichiometric conversion to biopterin or pterin and was …
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Building a Better Model for the Molybdenum Cofactor: A New Class of Molybdenum Dithiolene Complexes
… one dithiolene chelate, and a tricyclic pyranopterin ligand. It is present in all living things, and it participates in global carbon, nitrogen, and sulfur cycles. The exact role the ligand plays in enzymatic turnover is unknown, as crystal structures capture Moco at just one point in time. …
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Target Identification and Mechanism of Action Studies in Folate Metabolism in Kinetoplastids
… to study proteins involved in the essential pterin pathway. This pathway has not been extensively studied in kintoplastids, with the exception of PTR1 (by-pass protein for DHFR). The failure to synthesise pterin derivatives for bead coupling led to a fragment screening campaign being carried …
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Insect Development and Evolution: Perspectives on Individual and Colony-Level Phenotypes
… the evolution of bold phenotypes, and show that pterin pigments provide the primary source of coloration in U. ornatrix patterns. The final chapter focuses on the evolution of social phenotypes in insect societies. I suggest that the evolution of a physically differentiated reproductive and …
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Understanding the Role of Ligand Oxidation State: Design, Synthesis, and Reactivity of Electronically Asymmetric Molybdenum Dithiolene Complexes
Mononuclear molybdopterin enzymes are a large class of enzymes that are present in all phyla of life. All pterin containing enzymes posses a molybdopterin cofactor made up of a molybdenum metal center coordinated directly by a dithiolene ligand, which is appended to a pyranopterin cofactor. The …
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Structure- and Ligand-Based Design of Novel Antimicrobial Agents
… benzoic acid (<em>p</em>ABA) to dihydropterin pyrophosphate (DHPP) to form pteroic acid as a key step in bacterial folate biosynthesis. It is the traditional target of the sulfonamide class of antibiotics. Unfortunately, bacterial resistance and adverse effects have limited the clinical …
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ESTABLISHING PTERIDINE METABOLISM IN A BREAST CANCER CELL MODEL AND QUANTIFICATION OF SILVER NANOPARTICLE INTERACTIONS WITH YEAST CELLS USING MASS SPECTROMETRY
… in breast cancer cells were identified including pterin and isoxanthopterin, which yielded the first in vitro evidence for the cellular metabolisms behind previously reported elevated urinary pteridine levels in breast cancer patients, which could eventually lead to the development of a …
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Generating Small Molecule Fuels: (Photo)Electrochemical Catalysts
… methods as potential models for this pterin enzyme. Chapter 5 extends the studies of electrochemical nitrogen fixation by a tungsten hydrazido- complex at the synthetic and mechanistic levels. Photofixation of dinitrogen at a p-type silicon electrode via this hydrazide system is …
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Identification and Characterization of the Enzymes Involved in Biosynthesis of FAD and Tetrahydromethanopterin in Methanocaldococcus jannaschii
… pathway: methanofuran, tetrahydromethanopterin, coenzyme F₄₂₀, coenzyme M, coenzyme B, and coenzyme F₄₃₀. Although now it is known that some non-methanogenic archaea and bacteria have several of these coenzymes, they are named methanogenic coenzymes since these six coenzymes were first …
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More evidence for H2O2-mediated oxidative stress in vitiligo-increased epidermal DNA damage / repair.
… and we showed that both 7BH4 and 7-biopterin inhibit XO activity in a concentration dependent manner. Moreover, XO has the potential to bind to 6/7BH4 and 6/7-biopterin from the pterin/tyrosinase inhibitor complex. This discovery adds another receptor independent mechanism for …