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2009

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Articles 1 - 30 of 47

Full-Text Articles in Biotechnology

Applications Of Natural Products In The Control Of Mosquito-Transmitted Diseases, Jesse Hardin, Fatimah Linda Collier Jackson Dec 2009

Applications Of Natural Products In The Control Of Mosquito-Transmitted Diseases, Jesse Hardin, Fatimah Linda Collier Jackson

Department of Biology Faculty Publications

Mosquito-transmitted diseases remain one of the most significant causes of mortality in the African continent, despite successes in controlling these diseases in other regions of the world. The disproportionate impact in areas of poverty suggests a need for control that is efficient and does not require complex technological control strategies. Focusing on the vectors of disease, the mosquito, there are many alternatives to synthetic, chemical pesticides that await discovery and development. Although some natural products have been described, there is still a need for continuing research that incorporates endogenous knowledge in the selection process for potential vector control candidates. Recent …


Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh Dec 2009

Drosophila Adult Eye Model To Teach Scanning Electron Microscopy In An Undergraduate Cell Biology Laboratory, Meghana Tare, Oorvashi Roy Puli, Sarah M. Oros, Amit Singh

Biology Faculty Publications

We have devised an undergraduate laboratory exercise to study tissue morphology using fruit fly, Drosophila melanogaster, as the model organism. Drosophila can be reared in a cost effective manner in a short period of time. This experiment was a part of the undergraduate curriculum of the cell biology laboratory course aimed to demonstrate the use of scanning electron microscopy (SEM) technique to study the morphology of adult eye of Drosophila. The adult eye of Drosophila is a compound eye, which comprises of 800 unit eyes, and serves as an excellent model for SEM studies. We used flies that …


Quantifying And Resolving Multiple Vector Transformants In S. Cerevisiae Plasmid Libraries, Thomas C. Scanlon, Elizabeth C. Gray, Karl E. Griswold Nov 2009

Quantifying And Resolving Multiple Vector Transformants In S. Cerevisiae Plasmid Libraries, Thomas C. Scanlon, Elizabeth C. Gray, Karl E. Griswold

Dartmouth Scholarship

In addition to providing the molecular machinery for transcription and translation, recombinant microbial expression hosts maintain the critical genotype-phenotype link that is essential for high throughput screening and recovery of proteins encoded by plasmid libraries. It is known that Escherichia coli cells can be simultaneously transformed with multiple unique plasmids and thusly complicate recombinant library screening experiments. As a result of their potential to yield misleading results, bacterial multiple vector transformants have been thoroughly characterized in previous model studies. In contrast to bacterial systems, there is little quantitative information available regarding multiple vector transformants in yeast. Saccharomyces cerevisiae is the …


Artificial Intelligence – Ii: Retinal Image Blood Vessel Segmentation, M. Usman Akram, Anam Tariq, Shoab A. Khan Aug 2009

Artificial Intelligence – Ii: Retinal Image Blood Vessel Segmentation, M. Usman Akram, Anam Tariq, Shoab A. Khan

International Conference on Information and Communication Technologies

The appearance and structure of blood vessels in retinal images play an important role in diagnosis of eye diseases. This paper proposes a method for segmentation of blood vessels in color retinal images. We present a method that uses 2-D Gabor wavelet to enhance the vascular pattern. We locate and segment the blood vessels using adaptive thresholding. The technique is tested on publicly available DRIVE database of manually labeled images which has been established to facilitate comparative studies on segmentation of blood vessels in retinal images. The proposed method achieves an area under the receiver operating characteristic curve of 0.963 …


Exposure To Ultraviolet Radiation Causes Proteomic Changes In Embryos Of The Purple Sea Urchin, Strongylocentrotus Purpuratus, Joseph Paul Campanale Aug 2009

Exposure To Ultraviolet Radiation Causes Proteomic Changes In Embryos Of The Purple Sea Urchin, Strongylocentrotus Purpuratus, Joseph Paul Campanale

Master's Theses

The amount of solar ultraviolet radiation (UVR, 290-400 nm) reaching Earth’s surface is increasing due to ozone depletion and global climate change. Embryos of the purple sea urchin, Strongylocentrotus purpuratus, provide an ideal system for examining how UVR affects developing marine organisms and cells in general. To model the protein-mediated cell cycle response to UV-irradiation, six batches of S. purpuratus embryos were exposed to UVR, monitored for delays in the first mitotic division and examined for global proteomic changes. Embryos from each batch were exposed to or protected from artificial UVR for 25 or 60 min. Embryos treated with …


Rapid Evolution Of Sex-Pheromone-Producing Enzyme In Drosophila, Troy R. Shirangi, Héloïse D. Dufour, Thomas M. Williams, Sean B. Carroll Aug 2009

Rapid Evolution Of Sex-Pheromone-Producing Enzyme In Drosophila, Troy R. Shirangi, Héloïse D. Dufour, Thomas M. Williams, Sean B. Carroll

Biology Faculty Publications

A wide range of organisms use sex pheromones to communicate with each other and to identify appropriate mating partners. While the evolution of chemical communication has been suggested to cause sexual isolation and speciation, the mechanisms that govern evolutionary transitions in sex pheromone production are poorly understood. Here, we decipher the molecular mechanisms underlying the rapid evolution in the expression of a gene involved in sex pheromone production in Drosophilid flies. Long-chain cuticular hydrocarbons (e.g., dienes) are produced female-specifically, notably via the activity of the desaturase DESAT-F, and are potent pheromones for male courtship behavior in Drosophila melanogaster. We …


The Effect Of Endothelin-1 On The Expression Of Cdk Inhibitors P21 & P27 In Bovine Corneal Endothelial Cells, Lakshmi Reddy Bollu Jul 2009

The Effect Of Endothelin-1 On The Expression Of Cdk Inhibitors P21 & P27 In Bovine Corneal Endothelial Cells, Lakshmi Reddy Bollu

Masters Theses & Specialist Projects

Mammalian corneal endothelial cells are considered to be non-proliferative due to the arrest of cells at the G1 phase of the cell cycle. The purpose of this study was to determine whether the down regulation of cyclin dependant kinase inhibitors (p21cip1 and p27kip1) levels by Endothelin-1 (ET-1), would overcome the G1 phase arrest and promote cell cycle progression and proliferation in cultured BCECs (Bovine corneal endothelial cells). BCECs were isolated from bovine corneas and cultured in DMEM supplemented with 10% serum. 5-Bromo 2-deoxy Uridine (BrdU) incorporation was determined in serum starved cultures in 24-well plates as a measure of cell …


Differential Cellular Responses To Metal Oxide Based Nanoparticles And Potential Biomedical Applications, Cory L. Hanley Jul 2009

Differential Cellular Responses To Metal Oxide Based Nanoparticles And Potential Biomedical Applications, Cory L. Hanley

Boise State University Theses and Dissertations

The multidisciplinary field of nanotechnology has allowed for unprecedented exploration and manipulation of molecular, sub-molecular, and atomic structures and advancements in this field are revolutionizing scientific thought and applications. Within the field of nanotechnology, the branch of nanobiotechnology focuses on studying the effects of nanomaterials on biological systems and to elucidate how nanomaterials interact with cells and cellular components. Nanoparticles are a particular type of nanomaterial whose dimensions measure 100 nanometers and are shown to possess unique size-dependent physical, chemical and biological properties compared to their bulk counterparts. Metal oxide nanoparticles, such as those made from ZnO, are a type …


Final Report For The Link Energy Fellowship, A. Joe Shaw Jun 2009

Final Report For The Link Energy Fellowship, A. Joe Shaw

Link Foundation Energy Fellowship Reports

A sustainable energy future is critical for environmental and strategic reasons. Fossil fuel use has increased greenhouse gas emissions, and continued consumption could adversely change global climate. In addition, the United States must rely on foreign petroleum suppliers, leading to unfavorable trade deficits, instability, and conflict.1 One leading alternative to petroleum used for transportation is ethanol derived from cellulosic biomass.2 A major barrier for biological-based biomass conversion is a cost effective method of releasing sugars from recalcitrant cellulosic biomass by enzymatic hydrolysis. Thermophilic, anaerobic bacteria offer a potential solution, as they produce efficient native hydrolytic enzymes.3 However, all thermophilic bacteria …


Potential Role Of Micro-Algae On Global Energy Supply, Sage Callaway-Keeley, Stephanie Huynh Apr 2009

Potential Role Of Micro-Algae On Global Energy Supply, Sage Callaway-Keeley, Stephanie Huynh

Student Research Posters

The most effective ways to reduce CO2 emissions are to improve the energy efficiency of each economic sector and to reduce the cutting of tropical and temperate forests around the world. These options, however, may not fully reach their technical and economic potential due to various political and socioeconomic. The most practical of these is to increase CO2 sinks through photosynthesis in both standing tree biomass and in ocean primary producers. The use of marine algae as CO2 sinks is for large-scale CO2 mitigation: the use of phytoplankton through Fe fertilization and macro algal (kelp) farms, which can be used …


Biofuels: A Hands-On Approach, Learning The Potential Of Utilizing Non-Food Sources, Alexandra Ham, Gabrielle Pecora, Hoaithuong Bui, Timothy Camarella, Victor Pham, Marc Ting Apr 2009

Biofuels: A Hands-On Approach, Learning The Potential Of Utilizing Non-Food Sources, Alexandra Ham, Gabrielle Pecora, Hoaithuong Bui, Timothy Camarella, Victor Pham, Marc Ting

Student Research Posters

The global energy economy is huge and thoughts of replacing large amounts of petroleum based fuels by massive levels of fermentation of grains are not realistic. On an energy basis what global agriculture produces for food will almost cover the energy demands if all of it is redirected to the production of fuels—either as alcohols for gasoline or as fat derivatives for diesel fuel. This means that chemical processes need to be developed that allow inclusion of non-food based agricultural and urban wastes as well as forest debris into the energy economy. These represent opportunities to capture new sources of …


Altered Regulation Of Aquaporin Gene Expression In Allergen And Il-13-Induced Mouse Models Of Asthma, Carissa M. Krane, Bijia Deng, Venkateshwar Mutyam, Casey A. Mcdonald, Stephen Pazdziorko, Lawrence Mason, Samuel Goldman, Marion Kasaian, Divya Chaudhary, Cara Williams, Melisa W.Y. Ho Apr 2009

Altered Regulation Of Aquaporin Gene Expression In Allergen And Il-13-Induced Mouse Models Of Asthma, Carissa M. Krane, Bijia Deng, Venkateshwar Mutyam, Casey A. Mcdonald, Stephen Pazdziorko, Lawrence Mason, Samuel Goldman, Marion Kasaian, Divya Chaudhary, Cara Williams, Melisa W.Y. Ho

Biology Faculty Publications

IL-13 is known to affect many processes that contribute to an asthmatic phenotype, including inflammation, fibrosis, and mucus production. Members of the aquaporin (AQP) family of transmembrane water channels are targets of regulation in models of lung injury and inflammation. Therefore, we examined AQP mRNA and protein expression in allergen and IL-13-induced mouse models of asthma. Lungs from ovalbumin sensitized and ovalbumin challenged (OVA/OVA) and IL-13 treated mice showed airway thickening, increased mucus production, and pulmonary eosinophilia. Pulmonary function tests showed a significant increase in methacholine-induced airway hyperreactivity in OVA/OVA and IL-13-treated mice as compared with controls. Quantitative PCR analysis …


The Politics Of Genetically Modified Organisms: Global Rules, Local Needs, Ximena Gonzalez Apr 2009

The Politics Of Genetically Modified Organisms: Global Rules, Local Needs, Ximena Gonzalez

Independent Study Project (ISP) Collection

Biotechnology in regards to agriculture is complex and cannot be judged by a single factor. Exporters of GM foods have their reasons for exportation, and importing countries have their reasons to accept them. There is not a unified reason for acceptance or rejection. Countries may accept or reject for economic, social, or political reasons. Other countries may accept or reject for environmental and/or health reasons. However, there is the inevitable factor of influence. Some countries like the United States, and supernational powers like the European Union are major elements to the decision making process of developing countries. When it comes …


System Architecture For An Intelligent Implantable Bio-Telemetry Device, Karthik Kumar Nattamai Kumaresan Apr 2009

System Architecture For An Intelligent Implantable Bio-Telemetry Device, Karthik Kumar Nattamai Kumaresan

UNLV Theses, Dissertations, Professional Papers, and Capstones

Biotelemetry has long been used for environmental and life science research to study animal populations and behavior. The use of implantable bio-telemetric techniques makes it possible to record and study physiological variables during long-term experiments with a minimum disturbance to the animal. Fully implantable telemetric techniques greatly reduce the risk of infection associated with leads and catheters protruding from the skin. In this research the design and implementation of a completely programmable bio-implantable digital system which can measure two physiological signals extended over a period of time is considered. The proposed system consists of a standalone implantable transmitter unit and …


Biodiesel: Tomorrow's Fuel, Today's Solution, Roberto J. Molina, Racheal A. Persuad Mar 2009

Biodiesel: Tomorrow's Fuel, Today's Solution, Roberto J. Molina, Racheal A. Persuad

Undergraduate Research Conference

Study of physical and chemical properties of biodiesel fuels derived from poultry and plant fats.


Motivation In Spinoza And Rosenzweig Or Transgressing The Boundaries Of A Rationally Constructed Self, Jules Simon Mar 2009

Motivation In Spinoza And Rosenzweig Or Transgressing The Boundaries Of A Rationally Constructed Self, Jules Simon

Selected Works Temporary Series

No abstract provided.


Characterizing Bentgrass Distribution With Spatial And Biological Data To Support Ecological Risk Assessment In Connecticut, Carol Auer, Collin Ahrens, Jinwon Chung, Thomas Meyer Jan 2009

Characterizing Bentgrass Distribution With Spatial And Biological Data To Support Ecological Risk Assessment In Connecticut, Carol Auer, Collin Ahrens, Jinwon Chung, Thomas Meyer

Plant Science Presentations and Proceedings

Genetically-modified (GM) crops must be assessed before they are released into the environment. Our research examines the potential for gene flow and negative ecological impacts from the release of GM turfgrasses. Gene flow can produce hybrid offspring with transgenes and novel traits that could change the ability of the plant to survive and spread. If hybrid offspring have an advantage in the environment, they could become invasive and/or affect other components of our ecosystems. Creeping bentgrass (Agrostis stolonifera) is a common, non-native turfgrass that is a weed and could hybridize with other Agrostis species. At present, United States Department of …


Ecological Risk Assessment Of Switchgrass (Panicum Virgatum) In Connecticut., Carol Auer, Geoffrey Ecker Jan 2009

Ecological Risk Assessment Of Switchgrass (Panicum Virgatum) In Connecticut., Carol Auer, Geoffrey Ecker

Plant Science Presentations and Proceedings

A native of North America, switchgrass (Panicum virgatum) is a hardy rhizomatous perennial with an expansive range. The U.S. Department of Energy has identified switchgrass as a promising biofuel crop for low-input agriculture and marginal lands (Fig. 1). This has prompted research on improvement through genetic modification (GM). Before any new GM crop can be released, regulators must evaluate not only the modified plants, but also potential negative impacts to the environment. For example, hybridization between closely-related species could result in the transfer of GM traits to relatives (gene flow) creating new weeds or invasives. The objective of this research …


Sucrose Phosphate Synthase Expression Influences Poplar Phenology, Thomas Canam, Ji-Young Park, Kyu-Young Kang, Faride Unda, Shawn Mansfield Jan 2009

Sucrose Phosphate Synthase Expression Influences Poplar Phenology, Thomas Canam, Ji-Young Park, Kyu-Young Kang, Faride Unda, Shawn Mansfield

Faculty Research & Creative Activity

The objective of this study was to manipulate the intracellular pools of sucrose, and investigate its role in regulating plant growth, phenology (leaf senescence and bud break) and fibre development. This objective was achieved by differentially expressing an Arabidopsis (Arabidopsis thaliana L. Heynh.) sucrose phosphate synthase (SPS) gene in hybrid poplar (Populus alba · Populus grandidentata Michx.), a model system for tree biology with substantial industrial relevance in the context of short rotation forestry and a target bioenergy crop. Phenotypic differences were evident in the transgenic trees, as both the timing of bud flush and leaf senescence were altered compared …


Making Ethical Sense Of Useless Suffering With Levinas, Jules Simon Jan 2009

Making Ethical Sense Of Useless Suffering With Levinas, Jules Simon

Selected Works Temporary Series

No abstract provided.


The Ethical Phenomenon Of Gm-Corn: Anger, Anxiety, And Arrogance In Crossing American Borders, Jules Simon Jan 2009

The Ethical Phenomenon Of Gm-Corn: Anger, Anxiety, And Arrogance In Crossing American Borders, Jules Simon

Selected Works Temporary Series

In terms of phenomenology, I often wonder about the relevance of what I do as a philosopher for the life of those with whom I come into contact. This ‘coming into contact’ happens for me on several levels: as one human among many, as a husband and father and son and brother, as a teacher, as a neighbor, and as country or city dweller. I remember with fondness those times in the late sultry summer months when, as a youth, I would drive with my father to this or that local farm-stand on some remote back road in the hills …


Sucrose Phosphate Synthase Expression Influences Poplar Phenology, Thomas Canam, Ji-Young Park, Kyu-Young Kang, Faride Unda, Shawn D. Mansfield Jan 2009

Sucrose Phosphate Synthase Expression Influences Poplar Phenology, Thomas Canam, Ji-Young Park, Kyu-Young Kang, Faride Unda, Shawn D. Mansfield

Faculty Research & Creative Activity

The objective of this study was to manipulate the intracellular pools of sucrose, and investigate its role in regulating plant growth, phenology (leaf senescence and bud break) and fibre development. This objective was achieved by differentially expressing an Arabidopsis (Arabidopsis thaliana L. Heynh.) sucrose phosphate synthase (SPS) gene in hybrid poplar (Populus alba · Populus grandidentata Michx.), a model system for tree biology with substantial industrial relevance in the context of short rotation forestry and a target bioenergy crop. Phenotypic differences were evident in the transgenic trees, as both the timing of bud flush and leaf senescence were altered compared …


The Ethical Phenomenon Of Gm-Corn: Anger, Anxiety, And Arrogance In Crossing American Borders, Jules Simon Jan 2009

The Ethical Phenomenon Of Gm-Corn: Anger, Anxiety, And Arrogance In Crossing American Borders, Jules Simon

Departmental Papers (Philosophy)

In terms of phenomenology, I often wonder about the relevance of what I do as a philosopher for the life of those with whom I come into contact. This ‘coming into contact’ happens for me on several levels: as one human among many, as a husband and father and son and brother, as a teacher, as a neighbor, and as country or city dweller. I remember with fondness those times in the late sultry summer months when, as a youth, I would drive with my father to this or that local farm-stand on some remote back road in the hills …


Proteomic Analysis Of Endodontic Infections By Liquid Chromatography–Tandem Mass Spectrometry, R. Nandakumar, Nandakumar Madayiputhiya, A. F. Fouad Jan 2009

Proteomic Analysis Of Endodontic Infections By Liquid Chromatography–Tandem Mass Spectrometry, R. Nandakumar, Nandakumar Madayiputhiya, A. F. Fouad

Department of Biochemistry: Faculty Publications

Introduction—Endodontic infections are very prevalent and have a polymicrobial etiology characterized by complex interrelationships between endodontic microorganisms and the host defenses. Proteomic analysis of endodontic infections can provide global insights into the invasion, pathogenicity mechanisms, and multifactorial interactions existing between root canal bacteria and the host in the initiation and progression of apical periodontitis. The purpose of this study was to apply proteomic techniques such as liquid chromatography–tandem mass spectrometry (LC–MS/ MS) for the identification of proteins of bacterial origin present in endodontic infections.

Methods—Endodontic specimens were aseptically obtained from seven patients with root canal infections. Protein mixtures were subjected …


A New Pulsed Electric Field Therapy For Melanoma Disrupts The Tumor's Blood Supply And Causes Complete Remission Without Recurrence, Richard Nuccitelli, Xinhua Chen, Andrei G. Pakhomov, Wallace H. Baldwin, Saleh Sheikh, Jennifer L. Pomicter, Wei Ren, Chris Osgood, R. James Swanson, Juergen F. Kolb, Stephen J. Beebe, Karl H. Schoenbach Jan 2009

A New Pulsed Electric Field Therapy For Melanoma Disrupts The Tumor's Blood Supply And Causes Complete Remission Without Recurrence, Richard Nuccitelli, Xinhua Chen, Andrei G. Pakhomov, Wallace H. Baldwin, Saleh Sheikh, Jennifer L. Pomicter, Wei Ren, Chris Osgood, R. James Swanson, Juergen F. Kolb, Stephen J. Beebe, Karl H. Schoenbach

Bioelectrics Publications

We have discovered a new, ultrafast therapy for treating skin cancer that is extremely effective with a total electric field exposure time of only 180 mu sec. The application of 300 high-voltage (40 kV/cm), ultrashort (300 nsec) electrical pulses to murine melanomas in vivo triggers both necrosis and apoptosis, resulting in complete tumor remission within an average of 47 days in the 17 animals treated. None of these melanomas recurred during a 4-month period after the initial melanoma had disappeared. These pulses generate small, long-lasting, rectifying nanopores in the plasma membrane of exposed cells, resulting in increased membrane permeability to …


Electroporation For The Delivery Of Dna-Based Vaccines And Immunotherapeutics: Current Clinical Developments, Angela M. Bodles-Brakhop, Richard Heller, Ruxandra Draghia-Akli Jan 2009

Electroporation For The Delivery Of Dna-Based Vaccines And Immunotherapeutics: Current Clinical Developments, Angela M. Bodles-Brakhop, Richard Heller, Ruxandra Draghia-Akli

Bioelectrics Publications

Electroporation (EP) has been used in basic research for the past 25 years to aid in the transfer of DNA into cells in vitro. EP in vivo enhances transfer of DNA vaccines and therapeutic plasmids to the skin, muscle, tumors, and other tissues resulting in high levels of expression, often with serological and clinical benefits. the recent interest in nonviral gene transfer as treatment options for a vast array of conditions has resulted in the refinement and optimization of EP technology. current research has revealed that EP can be successfully used in many species, including humans. clinical trials are …


Hyaluronidase Activity Of Human Hyal1 Requires Active Site Acidic And Tyrosine Residues, Ling Zhang, Alamelu G. Bharadwaj, Andrew Casper, Joel Barkley, Joseph J. Barycki, Melanie A. Simpson Jan 2009

Hyaluronidase Activity Of Human Hyal1 Requires Active Site Acidic And Tyrosine Residues, Ling Zhang, Alamelu G. Bharadwaj, Andrew Casper, Joel Barkley, Joseph J. Barycki, Melanie A. Simpson

Department of Biochemistry: Faculty Publications

Hyaluronidases are a family of endolytic glycoside hydrolases

that cleave the β1–4 linkage between N-acetylglucosamine and

glucuronic acid in hyaluronan polymers via a substrate-assisted

mechanism. In humans, turnover of hyaluronan by this enzyme

family is critical for normal extracellular matrix remodeling.

However, elevated expression of the Hyal1 isozyme accelerates

tumor growth and metastatic progression. In this study, we used

structural information, site-directed mutagenesis, and steady

state enzyme kinetics to probe molecular determinants of

human Hyal1 function. Mutagenesis of active site residues

Glu131 and Tyr247 to Gln and Phe, respectively, eliminated activity

at all hyaluronan concentrations (to 125 …


Mechanistic Details Of Glutathione Biosynthesis Revealed By Crystal Structures Of Saccharomyces Cerevisiae Glutamate Cysteine Ligase, Ekaterina I. Biterova, Joseph J. Barycki Jan 2009

Mechanistic Details Of Glutathione Biosynthesis Revealed By Crystal Structures Of Saccharomyces Cerevisiae Glutamate Cysteine Ligase, Ekaterina I. Biterova, Joseph J. Barycki

Department of Biochemistry: Faculty Publications

Glutathione is a thiol-disulfide exchange peptide critical for

buffering oxidative or chemical stress, and an essential cofactor

in several biosynthesis and detoxification pathways. The ratelimiting

step in its de novo biosynthesis is catalyzed by glutamate

cysteine ligase, a broadly expressed enzyme for which limited

structural information is available in higher eukaryotic species.

Structural data are critical to the understanding of clinical glutathione

deficiency, as well as rational design of enzyme modulators

that could impact human disease progression. Here, we

have determined the structures of Saccharomyces cerevisiae glutamate

cysteine ligase (ScGCL) in the presence of glutamate and

MgCl2 (2.1 Å; R …


Modulation Of The Heme Electronic Structure And Cystathionine Β-Synthase Activity By Second Coordination Sphere Ligands: The Role Of Heme Ligand Switching In Redox Regulation, Sangita Singh, Peter Madzelan, Jay Stasser, Colin L. Weeks, Donald F. Becker, Thomas G. Spiro, James Penner-Hahn, Ruma Banerjee Jan 2009

Modulation Of The Heme Electronic Structure And Cystathionine Β-Synthase Activity By Second Coordination Sphere Ligands: The Role Of Heme Ligand Switching In Redox Regulation, Sangita Singh, Peter Madzelan, Jay Stasser, Colin L. Weeks, Donald F. Becker, Thomas G. Spiro, James Penner-Hahn, Ruma Banerjee

Department of Biochemistry: Faculty Publications

In humans, cystathionine β-synthase (CBS) is a hemeprotein, which catalyzes a pyridoxal phosphate (PLP)-dependent condensation reaction. Changes in the heme environment are communicated to the active site, which is ~20 Å away. In this study, we have examined the role of H67 and R266, which are in the second coordination sphere of the heme ligands, H65 and C52 respectively, in modulating the heme's electronic properties and in transmitting information between the heme and active sites. While the H67A mutation is comparable to wild-type CBS, interesting differences are revealed by mutations at the R266 site. The pathogenic mutant, R266K, is moderately …


Heme Regulation Of Human Cystathionine Β-Synthase Activity: Insights From Fluorescence And Raman Spectroscopy, Colin L. Weeks, Sangita Singh, Peter Madzelan, Ruma Banerjee, Thomas G. Spiro Jan 2009

Heme Regulation Of Human Cystathionine Β-Synthase Activity: Insights From Fluorescence And Raman Spectroscopy, Colin L. Weeks, Sangita Singh, Peter Madzelan, Ruma Banerjee, Thomas G. Spiro

Department of Biochemistry: Faculty Publications

Cystathionine β-synthase (CBS) plays a central role in cysteine metabolism, and malfunction of the enzyme leads to homocystinuria, a devastating metabolic disease. CBS contains a pyridoxal 5′- phosphate (PLP) cofactor which catalyzes the synthesis of cystathionine from homocysteine and serine. Mammalian forms of the enzyme also contain a heme group, which is not involved in catalysis. It may, however, play a regulatory role, since the enzyme is inhibited when CO or NO are bound to the heme. We have investigated the mechanism of this inhibition using fluorescence and resonance Raman spectroscopies. CO binding is found to induce a tautomeric shift …