Harry B. Gray

Pennsylvania State University, University Park, Maryland, United States

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Publications (988)6835.08 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: We constructed two artificial multiple-step electron transfer (hopping) systems based on Pseudomonas aeruginosa azurin where a tyrosine (YOH) is situated between Ru(2,2′-bipyridine)2(imidazole)(histidine) and the native copper site: RuH107YOH109 and RuH124-YOH122. We investigated the rates of CuI oxidation by flash-quench generated RuIII over a range of conditions that probed the role of proton-coupled oxidation/reduction of YOH in the reaction. Rates of CuI oxidation were enhanced over single-step electron transfer by factors between 3 and 80, depending on specific scaffold and buffer conditions.
    No preview · Article · Jan 2016 · JBIC Journal of Biological Inorganic Chemistry
  • Source
    Jay R. Winkler · Harry B. Gray
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    ABSTRACT: Biological electron transfers often occur between metal-containing cofactors that are separated by very large molecular distances. Employing photosensitizer-modified iron and copper proteins, we have shown that single-step electron tunneling can occur on nanosecond to microsecond timescales at distances between 15 and 20 Å. We also have shown that charge transport can occur over even longer distances by hole hopping (multistep tunneling) through intervening tyrosines and tryptophans. In this perspective, we advance the hypothesis that such hole hopping through Tyr/Trp chains could protect oxygenase, dioxygenase, and peroxidase enzymes from oxidative damage. In support of this view, by examining the structures of P450 (CYP102A) and 2OG-Fe (TauD) enzymes, we have identified candidate Tyr/Trp chains that could transfer holes from uncoupled high-potential intermediates to reductants in contact with protein surface sites.
    Preview · Article · Nov 2015 · Quarterly Reviews of Biophysics
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    ABSTRACT: We have developed a model to study the role of geometrical factors in influencing the early stages of unfolding in three cytochromes: cyt c', cyt c-b562 and cyt c. Each stage in unfolding is quantified by the spatial extension λ̂i of n-residue segments, and by their angular extension 〈βn〉. Similarities and differences between and among the three cytochromes in the unfolding of helical and non-helical regions can be determined by analyzing the data for each signature separately. Definite conclusions can be drawn when spatial and angular changes are considered in tandem. To facilitate comparisons, we present graphical portraits of the three cytochromes at the same stage of unfolding, and in relation to their native state structures. We also display specific segments at different stages of unfolding to illustrate differences in stability of defined domains thereby allowing us to make specific predictions on the unfolding of corresponding internal and terminal helices in cyt c' and cyt c-b562. Our work accords with an earlier experimental report on the presence and persistence of a hydrophobic core in cyt c.
    No preview · Article · Nov 2015 · Journal of inorganic biochemistry
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    Julia G Lyubovitsky · Harry B Gray · Jay R Winkler

    Full-text · Dataset · Nov 2015
  • Kara L. Bren · Richard Eisenberg · Harry B. Gray
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    ABSTRACT: Two articles published by Pauling and Coryell in PNAS nearly 80 years ago described in detail the magnetic properties of oxy- and deoxyhemoglobin, as well as those of closely related compounds containing hemes. Their measurements revealed a large difference in magnetism between oxygenated and deoxygenated forms of the protein and, along with consideration of the observed diamagnetism of the carbonmonoxy derivative, led to an electronic structural formulation of oxyhemoglobin. The key role of hemoglobin as the main oxygen carrier in mammalian blood had been established earlier, and its allosteric behavior had been described in the 1920s. The Pauling-Coryell articles on hemoglobin represent truly seminal contributions to the field of bioinorganic chemistry because they are the first to make connections between active site electronic structure and the function of a metalloprotein.
    No preview · Article · Oct 2015 · Proceedings of the National Academy of Sciences
  • Harry B Gray · Jay R Winkler
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    ABSTRACT: Living organisms have adapted to atmospheric dioxygen by exploiting its oxidizing power while protecting themselves against toxic side effects. Reactive oxygen and nitrogen species formed during oxidative stress, as well as high-potential reactive intermediates formed during enzymatic catalysis, could rapidly and irreversibly damage polypeptides were protective mechanisms not available. Chains of redox-active tyrosine and tryptophan residues can transport potentially damaging oxidizing equivalents (holes) away from fragile active sites and toward protein surfaces where they can be scavenged by cellular reductants. Precise positioning of these chains is required to provide effective protection without inhibiting normal function. A search of the structural database reveals that about one third of all proteins contain Tyr/Trp chains composed of three or more residues. Although these chains are distributed among all enzyme classes, they appear with greatest frequency in the oxidoreductases and hydrolases. Consistent with a redox-protective role, approximately half of the dioxygen-using oxidoreductases have Tyr/Trp chain lengths ≥3 residues. Among the hydrolases, long Tyr/Trp chains appear almost exclusively in the glycoside hydrolases. These chains likely are important for substrate binding and positioning, but a secondary redox role also is a possibility.
    No preview · Article · Sep 2015 · Proceedings of the National Academy of Sciences
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    ABSTRACT: W(CNAryl)6 complexes containing 2,6-diisopropylphenyl isocyanide (CNdipp) are powerful photoreductants with strongly emissive long-lived excited states. These properties are enhanced upon appending another aryl ring, e.g., W(CNdippPh(OMe2))6; CNdippPh(OMe2) = 4-(3,5-dimethoxyphenyl)-2,6-diisopropylphenylisocyanide ( Sattler et al. J. Am. Chem. Soc. 2015 , 137 , 1198 - 1205 ). Electronic transitions and low-lying excited states of these complexes were investigated by time-dependent density functional theory (TDDFT); the lowest triplet state was characterized by time-resolved infrared spectroscopy (TRIR) supported by density functional theory (DFT). The intense absorption band of W(CNdipp)6 at 460 nm and that of W(CNdippPh(OMe2))6 at 500 nm originate from transitions of mixed ππ*(C≡N-C)/MLCT(W → Aryl) character, whereby W is depopulated by ca. 0.4 e(-) and the electron-density changes are predominantly localized along two equatorial molecular axes. The red shift and intensity rise on going from W(CNdipp)6 to W(CNdippPh(OMe2))6 are attributable to more extensive delocalization of the MLCT component. The complexes also exhibit absorptions in the 300-320 nm region, owing to W → C≡N MLCT transitions. Electronic absorptions in the spectrum of W(CNXy)6 (Xy = 2,6-dimethylphenyl), a complex with orthogonal aryl orientation, have similar characteristics, although shifted to higher energies. The relaxed lowest W(CNAryl)6 triplet state combines ππ* excitation of a trans pair of C≡N-C moieties with MLCT (0.21 e(-)) and ligand-to-ligand charge transfer (LLCT, 0.24-0.27 e(-)) from the other four CNAryl ligands to the axial aryl and, less, to C≡N groups; the spin density is localized along a single Aryl-N≡C-W-C≡N-Aryl axis. Delocalization of excited electron density on outer aryl rings in W(CNdippPh(OMe2))6 likely promotes photoinduced electron-transfer reactions to acceptor molecules. TRIR spectra show an intense broad bleach due to ν(C≡N), a prominent transient upshifted by 60-65 cm(-1), and a weak down-shifted feature due to antisymmetric C≡N stretch along the axis of high spin density. The TRIR spectral pattern remains unchanged on the femtosecond-nanosecond time scale, indicating that intersystem crossing and electron-density localization are ultrafast (<100 fs).
    No preview · Article · Aug 2015 · Inorganic Chemistry
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    ABSTRACT: An n+p-Si microwire array coupled with a two-layer catalyst film consisting of Ni–Mo nanopowder and TiO2 light-scattering nanoparticles has been used to simultaneously achieve high fill factors and light-limited photocurrent densities from photocathodes that produce H2(g) directly from sunlight and water. The TiO2 layer scattered light back into the Si microwire array, while optically obscuring the underlying Ni–Mo catalyst film. In turn, the Ni–Mo film had a mass loading sufficient to produce high catalytic activity, on a geometric area basis, for the hydrogen-evolution reaction. The best-performing microwire array devices prepared in this work exhibited short-circuit photocurrent densities of −14.3 mA cm−2, photovoltages of 420 mV, and a fill factor of 0.48 under 1 Sun of simulated solar illumination, whereas the equivalent planar Ni–Mo-coated Si device, without TiO2 scatterers, exhibited negligible photocurrent due to complete light blocking by the Ni–Mo catalyst layer.
    No preview · Article · Aug 2015 · Energy & Environmental Science
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    ABSTRACT: Two-photon absorption spectroscopy (TPAS) is a powerful spect electronic structures of excited states that are not accessible under one-p TPAS in microscopy and photodynamic therapy are growing, as two- pho penetrate biol. tissues. While there is both a fundamental and prac properties of dyes and other photoactive compds., lab. studies are cons and optics required to cover a broad tuning range. We demonstrate h pumped OPO system can be utilized to obtain TPA spectra of inorg. comp obtained TPA spectra for the ruthenium(II) bipyridyl complex, Ru(bpy)_3^(2+) photoreductants. We show that this methodol. can be further extended metal carbonyl compds.
    No preview · Conference Paper · Aug 2015
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    ABSTRACT: Sustainable energy solns. impact every aspect of human life. National security, health, access to clean water, the extent of climate change, and biodiversity all critically depend on the global availability of clean, affordable energy. The sun is our most abundant source of energy; more energy from sunlight strikes earth within a single hour than mankind consumes per yr. To sustainably power the planet, sunlight capture, charge transport, and catalysis are needed for fuel prodn. through water splitting. Water oxidn. provides reducing equiv. through a complex four-electron transfer process. Sufficiently active, robust, earth-abundant catalysts for this important reaction are much needed yet still elusive; they will only be discovered through rational catalyst design guided by mechanistic insights into individual reaction steps. We recently reported highly efficient [NiFe] - layered double hydroxide water oxidn. nanocatalysts [Hunter, Blakemore, Deimund, Gray, Winkler, Mueller, J. 2014, 136, 13118]. To gain mechanistic information, several in-situ electrochem. spectroscopies (i.e. IR, Raman, EPR, and x-ray absorption spectroscopies) have been developed, by which transient species during catalytic turnover were detected. We applied potentials to the catalyst nanosheets, at which in aq. electrolyte water oxidn. would occur, but instead we used non-aq. media to halt the catalytic cycle; strategic injection of water led to turnover, and short-lived species could be identified. This way, we obtained exptl. evidence for intermediates required for efficient water oxidn.
    No preview · Conference Paper · Aug 2015
  • Conference Paper: Solar fuels
    Harry B. Gray
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    ABSTRACT: Investigators in the NSF CCI Solar Fuels Program are working on syntheses of light absorbers and catalysts to be components in devices for solardriven water splitting. Catalysts both for water oxidn. to dioxygen (OER) and prot dihydrogen (HER) have been fully characterized. Promising HER heterogeneous catalysts include Ni- Mo nanopowd (Ni, Co) phosphides, which reduce protons in acidic aq. solns. with catalytic efficiencies near that of platinum. PIs Fuels also are investigating homogeneous iron, cobalt, and nickel complexes that catalyze H2 prodn. from protic relatively low overpotentials. Both exptl. and theor. work has shed light on the mechanisms of these reactions. A new photoanode materials, tantalum nitrides and dinitrogen- intercalated tungsten oxide are esp. promising. Also theor. and exptl. study are bismuth vanadate photoanode- catalyst materials; and, in recent work, a promising me synthesis of mixed- metal- oxide water oxidn. catalysts, pulsed laser ablation in liqs. (PLAL) , has been developed. S nanocryst. materials, including a highly active Ni, Fe, Ln, Ti- oxide nanosheet OER catalyst, have been obtained by P.
    No preview · Conference Paper · Aug 2015
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    ABSTRACT: Water-soluble corroles with inherent fluorescence can form stable self-assemblies with tumor-targeted cell penetration proteins, and have been explored as agents for optical imaging and photosensitization of tumors in pre-clinical studies. However, the limited tissue-depth of excitation wavelengths limits their clinical applicability. To examine their utility in more clinically-relevant imaging and therapeutic modalities, here we have explored the use of corroles as contrast enhancing agents for magnetic resonance imaging (MRI), and evaluated their potential for tumor-selective delivery when encapsulated by a tumor-targeted polypeptide. We have found that a manganese-metallated corrole exhibits significant T1 relaxation shortening and MRI contrast enhancement that is blocked by particle formation in solution but yields considerable MRI contrast after tissue uptake. Cell entry but not low pH enables this. Additionally, the corrole elicited tumor-toxicity through the loss of mitochondrial membrane potential and cytoskeletal breakdown when delivered by the targeted polypeptide. The protein-corrole particle (which we call HerMn) exhibited improved therapeutic efficacy compared to current targeted therapies used in the clinic. Taken together with its tumor-preferential biodistribution, our findings indicate that HerMn can facilitate tumor-targeted toxicity after systemic delivery and tumor-selective MR imaging activatable by internalization. Copyright © 2015. Published by Elsevier B.V.
    Full-text · Article · Aug 2015 · Journal of Controlled Release
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    ABSTRACT: Global sustainable energy solns. remain one of the greatest challenges of the 21st century. Health and climate risks assocd. with combustion of fossil fuels threaten global stability, development and national security. The sun is the most abundant and cleanest source of energy, but its intermittence on earth and unequal local energy needs require conversion into stored fuels. Chem. can meet this challenge by solar-driven water splitting with earth-abundant, efficient and robust materials. Water oxidn. is central to the prodn. of storable chem. fuels, since ample supply of cleanly, efficiently, and affordably generated protons and electrons is a prerequisite for all sustainable chem. transformations. Pulsed-laser ablation in liqs. (PLAL) is a flexible synthetic strategy to prep. earth-abundant, surfactant-free, mixed-metal (hydrous) oxide nanoparticle water oxidn. catalysts [Blakemore, Gray, Winkler, Mueller, ACS Catal. 2013, 3, 2497]. It offers size and compn. control through multiple tuneable parameters (e.g. laser pulse energy and elemental content in the ablation target and liq.). With PLAL, many different nanocatalysts can readily be synthesized and screened for water oxidn. activity, rendering PLAL a medium-throughput method for catalyst design. We prepd. a series of Ni-Fe materials and systematically varied Fe content. Oxygen evolution activity in basic electrolyte increased as Fe content decreased to 22%. Addn. of Ti^(4+) and La^(3+) ions further enhanced electrocatalysis, reaching 10 mA cm^(-2) at 260 mV overpotential; on a flat working electrode, this is the lowest overpotential to date for Fe-Ni catalysts. We spectroscopically identified [Ni-Fe]-layered double hydroxide nanosheets with intercalated nitrate and water, [Ni_(1-x)Fe_x(OH_2)](NO_3)_y(OH)_(x-y)•nH_2O, as the most active precatalyst. Higher turnover frequencies were obsd. with a greater relative proportion of a 405.1 eV N 1s (XPS binding energy) species in the nanosheets [Hunter, Blakemore, Deimund, Gray, Winkler, Mueller, J. Am. Chem. Soc. 2014, 136, 13118]. The effect of different intercalated anions on water oxidn. activity was investigated.
    No preview · Conference Paper · Aug 2015
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    ABSTRACT: Cobaloximes are a series of macrocyclic cobalt complexes that have been shown to catalyze the hydrogen evolution reaction (HER) at low overpotentials. There has been much debate about the mechanism of this reaction, particularly with regard to H-H bond formation. As catalysts that operate close to the thermodn. potential, cobaloximes show some degree of reversibility, oxidizing hydrogen in the presence of base to form the conjugate acid. Presented here are kinetic studies of the cobaloxime-mediated oxidn. of hydrogen in the presence of base. Insight into the bifurcation between homolytic and heterolytic mechanisms of cobaloximecatalyzed HER is gained by studying the microscopic reverse reaction.
    No preview · Conference Paper · Aug 2015
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    ABSTRACT: Corroles have been shown experimentally to cause cell cycle arrest, and there is some evidence that this might be attributed to an inhibitory effect of corroles on Heat shock protein 90 (Hsp90), which is known to play a vital role in cancer cell proliferation. In this study, we used molecular dynamics to examine the interaction of gallium corroles with Hsp90, and found that it can bind preferentially to the ATP-binding N-terminal site. We also found that structural variations of the corrole ring can influence the binding energies and affinities of the corrole to Hsp90. We predict that both the bis-carboxylated corrole (4-Ga) and a proposed 3,17-bis-sulfonated corrole (7-Ga) are promising alternatives to Ga(III) 5,10,15-tris(pentafluorophenyl)-2,17-bis(sulfonic acid)-corrole (1-Ga) as anti-cancer agents.
    No preview · Article · Jul 2015 · Molecular BioSystems
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    ABSTRACT: The electrocatalytic performance for hydrogen evolution has been evaluated for radial-junction n+p-Si microwire (MW) arrays with Pt or cobalt phosphide, CoP, nanoparticulate catalysts in contact with 0.50 M H2SO4(aq). The CoP-coated (2.0 mg cm-2) n+p-Si MW photocathodes were stable for over 12 h of continuous operation and produced an open-circuit photovoltage (Voc) of 0.48 V, a light-limited photocurrent density (Jph) of 17 mA cm-2, a fill factor (ff) of 0.24, and an ideal regenerative cell efficiency (ηIRC) of 1.9% under simulated 1 Sun illumination. Pt-coated (0.5 mg cm-2) n+p-Si MW-array photocathodes produced Voc = 0.44 V, Jph = 14 mA cm-2, ff = 0.46, and η = 2.9% under identical conditions. Thus, the MW geometry allows the fabrication of photocathodes entirely comprised of earth-abundant materials that exhibit performance comparable to that of devices that contain Pt.Keywords: silicon; cobalt phosphide; hydrogen evolution; platinum; microwires; solar fuel
    No preview · Article · May 2015 · Journal of Physical Chemistry Letters
  • Andrew K. Udit · Michael G. Hill · Harry B. Gray
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    ABSTRACT: This chapter reviews the efforts to develop catalytically competent P450 systems in which a simple electrode replaces NAD(P)H, and in some instances native reductase proteins, in the catalytic cycle. Notably, in evaluating the successes of P450 electrocatalytic methods, there is an important distinction to be made between mammalian and bacterial systems. While some mention of notable mammalian P450 electrocatalytic systems is made, the chapter focuses primarily on bacterial systems and specifically on the NADPH dependent flavocytochrome P450 from Bacillus megaterium (BM3). Harnessing P450 activity for in vitro applications may be most simply accomplished with electrochemical systems utilizing soluble mediators. Protein–surfactant film voltammetry has been widely used for studying the redox chemistry of P450s. Another striking aspect of P450 electrochemistry in surfactant films is the dramatic shift of the FeIII/II couple to positive potentials. Finally, mediated electrochemical P450 systems are perhaps the best bets for large-scale biocatalysis.
    No preview · Article · May 2015
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    ABSTRACT: The mechanistic features of oligomerization and oxidative cyclization steps in the synthesis of tris(pentafluorophenyl)corrole (1) have been thoroughly studied. Separation of the intermediates by preparative HPLC and analysis by NMR spectroscopy and high resolution mass spectrometry allowed for the identification of product-forming intermediates and monitoring of undesired byproducts. Conditions for complete end-capping with pyrrole were optimized for improved yields of oligomers leading to the desired corrole 1. A yield of 84 % was achieved during oxidation of an isolated precursor; the overall yield of 1 was 17.0 %.
    No preview · Article · Apr 2015 · European Journal of Organic Chemistry
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    ABSTRACT: Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UV-Vis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.
    Preview · Article · Mar 2015 · Journal of Visualized Experiments
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chemotherapy often involves broad-spectrum cytotoxic agents with many side effects and limited targeting. Corroles are a class of tetrapyrrolic macrocycles that exhibit differential cytostatic and cytotoxic properties in specific cell lines, depending on the identities of the chelated metal and functional groups. The unique behavior of functionalized corroles towards specific cell lines introduces the possibility of targeted chemotherapy. Many anticancer drugs are evaluated by their ability to inhibit RNA transcription. Here we present a step-by-step protocol for RNA transcription in the presence of known and potential inhibitors. The evaluation of the RNA products of the transcription reaction by gel electrophoresis and UVVis spectroscopy provides information on inhibitive properties of potential anticancer drug candidates and, with modifications to the assay, more about their mechanism of action. Little is known about the molecular mechanism of action of corrole cytotoxicity. In this experiment, we consider two corrole compounds: gallium(III) 5,10,15-(tris)pentafluorophenylcorrole (Ga(tpfc)) and freebase analogue 5,10,15-(tris)pentafluorophenylcorrole (tpfc). An RNA transcription assay was used to examine the inhibitive properties of the corroles. Five transcription reactions were prepared: DNA treated with Actinomycin D, triptolide, Ga(tpfc), tpfc at a [complex]:[template DNA base] ratio of 0.01, respectively, and an untreated control. The transcription reactions were analyzed after 4 hr using agarose gel electrophoresis and UV-Vis spectroscopy. There is clear inhibition by Ga(tpfc), Actinomycin D, and triptolide. This RNA transcription assay can be modified to provide more mechanistic detail by varying the concentrations of the anticancer complex, DNA, or polymerase enzyme, or by incubating the DNA or polymerase with the complexes prior to RNA transcription; these modifications would differentiate between an inhibition mechanism involving the DNA or the enzyme. Adding the complex after RNA transcription can be used to test whether the complexes degrade or hydrolyze the RNA. This assay can also be used to study additional anticancer candidates.
    No preview · Article · Mar 2015 · Journal of Visualized Experiments

Publication Stats

41k Citations
6,835.08 Total Impact Points

Institutions

  • 1975-2015
    • Pennsylvania State University
      • • Department of Chemical Engineering
      • • Department of Chemistry
      University Park, Maryland, United States
    • The Cooper Union for the Advancement of Science and Art
      • Department of Chemistry
      New York, New York, United States
  • 1970-2015
    • University of Illinois, Urbana-Champaign
      • Department of Chemistry
      Urbana, Illinois, United States
  • 1968-2015
    • California Institute of Technology
      • • Beckman Institute
      • • Division of Chemistry and Chemical Engineering
      • • Jet Propulsion Laboratory
      • • Arthur Amos Noyes Laboratory of Chemical Physics
      Pasadena, California, United States
  • 1988-2012
    • Technion - Israel Institute of Technology
      • Schulich Faculty of Chemistry
      H̱efa, Haifa, Israel
    • University of Pittsburgh
      • Department of Chemistry
      Pittsburgh, Pennsylvania, United States
  • 2011
    • Beckman Research Institute
      Duarte, California, United States
  • 2009
    • Lake Tahoe Community College
      South Lake Tahoe, California, United States
  • 2008
    • University of California, Los Angeles
      Los Ángeles, California, United States
  • 2007
    • Occidental College
      • Department of Chemistry
      Los Angeles, California, United States
  • 2006
    • University of Zurich
      • Institut für Anorganische Chemie
      Zürich, Zurich, Switzerland
    • Bar Ilan University
      • Department of Chemistry
      Gan, Tel Aviv, Israel
  • 2005
    • The University of Arizona
      Tucson, Arizona, United States
  • 1981-2005
    • Stanford University
      • • Department of Biochemistry
      • • Department of Chemistry
      Palo Alto, California, United States
  • 2004
    • University of London
      Londinium, England, United Kingdom
  • 2003
    • Polytechnic University of Puerto Rico
      San Juan, San Juan, Puerto Rico
    • Iowa State University
      Ames, Iowa, United States
  • 1995-2003
    • University of Florence
      • Magnetic Resonance Center (CERM)
      Florens, Tuscany, Italy
  • 1962-2003
    • Northwestern University
      • Department of Cell and Molecular Biology
      Evanston, Illinois, United States
    • IT University of Copenhagen
      København, Capital Region, Denmark
  • 2002
    • Tel Aviv University
      Tell Afif, Tel Aviv, Israel
  • 1998
    • Newcastle University
      • School of Chemistry
      Newcastle-on-Tyne, England, United Kingdom
    • Wabash College
      • Chemistry
      کرافوردزویل، ایندیانا, Indiana, United States
  • 1997
    • University of Gothenburg
      Goeteborg, Västra Götaland, Sweden
  • 1987-1996
    • Los Alamos National Laboratory
      Los Alamos, California, United States
  • 1968-1996
    • Pasadena City College
      Pasadena, Texas, United States
  • 1990
    • Brookhaven National Laboratory
      • Chemistry Department
      New York, New York, United States
  • 1963-1989
    • Columbia University
      • Department of Chemistry
      New York, New York, United States
  • 1984
    • University of California, Davis
      • Department of Chemistry
      Davis, California, United States
    • Chalmers University of Technology
      • Division of Chemical Physics
      Goeteborg, Västra Götaland, Sweden
  • 1979-1980
    • University of Toronto
      • Department of Chemistry
      Toronto, Ontario, Canada
    • University of Padova
      Padua, Veneto, Italy
  • 1976-1980
    • University of California, Santa Cruz
      Santa Cruz, California, United States
  • 1974-1979
    • Massachusetts Institute of Technology
      • Department of Chemistry
      Cambridge, Massachusetts, United States
    • University of Canterbury
      • Department of Chemistry
      Christchurch, Canterbury, New Zealand
    • McGill University
      • Department of Chemistry
      Montréal, Quebec, Canada
  • 1978
    • University of Rochester
      • Department of Chemistry
      Rochester, New York, United States