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Full-Text Articles in Physical Sciences and Mathematics
Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro
Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro
Gilles Muller
4-(2-Methylbutyl)aminodipicolinic acid (H2MEBADPA) has been synthesized and fully characterized in terms of aqueous phase protonation constants (pKa's) and photophysical measurements. The pKa's were determined by spectrophotometric titrations, utilizing a fully sealed titration system. Photophysical measurements consisted of room temperature fluorescence and frozen solution phosphorescence as well as quantum yield determinations at various pH, which showed that only fully deprotonated MEBADPA2– is appreciably emissive. The fluorescence of MEBADPA2– has been determined to be quenched by hydroxide and methoxide anions, most likely through base-catalyzed excited-state tautomerism or proton transfer. This quenching phenomenon has been quantitatively explored through steady-state and time-resolved fluorescence measurements. …
Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro
Speciation, Luminescence, And Alkaline Fluorescence Quenching Of 4-(2-Methylbutyl)Aminodipicolinic Acid (H2mebadpa), Gilles Muller, A. J. Ingram, A. G. Dunpal, R. Dipietro
Faculty Publications, Chemistry
4-(2-Methylbutyl)aminodipicolinic acid (H2MEBADPA) has been synthesized and fully characterized in terms of aqueous phase protonation constants (pKa's) and photophysical measurements. The pKa's were determined by spectrophotometric titrations, utilizing a fully sealed titration system. Photophysical measurements consisted of room temperature fluorescence and frozen solution phosphorescence as well as quantum yield determinations at various pH, which showed that only fully deprotonated MEBADPA2– is appreciably emissive. The fluorescence of MEBADPA2– has been determined to be quenched by hydroxide and methoxide anions, most likely through base-catalyzed excited-state tautomerism or proton transfer. This quenching phenomenon has been quantitatively explored through steady-state and time-resolved fluorescence measurements. …
A Promising Change In The Selection Of The Circular Polarization Excitation Used In The Measurement Of Eu(Iii) Circularly Polarized Luminescence, K. Do, F. C. Muller, Gilles Muller
A Promising Change In The Selection Of The Circular Polarization Excitation Used In The Measurement Of Eu(Iii) Circularly Polarized Luminescence, K. Do, F. C. Muller, Gilles Muller
Faculty Publications, Chemistry
A judicious change in the selected transition used for circular polarization excitation will overcome the low oscillator strength limitation of the currently allowed magnetic-dipole 5D1 ← 7F2 (Eu(III)) transition chosen for circularly polarized luminescence (CPL) measurement. The proposed allowed magnetic-dipole 5D1 ← 7F0 (Eu(III)) transition will facilitate the detection of CPL from the Eu(III) systems of interest. CPL on the acetonitrile solution of the chiral tris complex of Eu(III) with (R,R)-N,N′-bis(1-phenylethyl)-2,6-pyridinedicarboxamide ([Eu((R,R)-1)3]3+), recently suggested as an effective and reliable CPL calibrating agent, confirms the feasibility of the proposed experimental procedure. A comparable CPL activity exhibited by the acetonitrile solution of …
A Promising Change In The Selection Of The Circular Polarization Excitation Used In The Measurement Of Eu(Iii) Circularly Polarized Luminescence, K. Do, F. C. Muller, Gilles Muller
A Promising Change In The Selection Of The Circular Polarization Excitation Used In The Measurement Of Eu(Iii) Circularly Polarized Luminescence, K. Do, F. C. Muller, Gilles Muller
Gilles Muller
A judicious change in the selected transition used for circular polarization excitation will overcome the low oscillator strength limitation of the currently allowed magnetic-dipole 5D1 ← 7F2 (Eu(III)) transition chosen for circularly polarized luminescence (CPL) measurement. The proposed allowed magnetic-dipole 5D1 ← 7F0 (Eu(III)) transition will facilitate the detection of CPL from the Eu(III) systems of interest. CPL on the acetonitrile solution of the chiral tris complex of Eu(III) with (R,R)-N,N′-bis(1-phenylethyl)-2,6-pyridinedicarboxamide ([Eu((R,R)-1)3]3+), recently suggested as an effective and reliable CPL calibrating agent, confirms the feasibility of the proposed experimental procedure. A comparable CPL activity exhibited by the acetonitrile solution of …
Farnesylated Lamins, Progeroid Syndromes And Farnesyl Transferase Inhibitors, Michael Sinensky, A. E. Rusinol
Farnesylated Lamins, Progeroid Syndromes And Farnesyl Transferase Inhibitors, Michael Sinensky, A. E. Rusinol
Faculty Publications, Biological Sciences
Three mammalian nuclear lamin proteins, lamin B1, lamin B2 and the lamin A precursor, prelamin A, undergo canonical farnesylation and processing at CAAX motifs. In the case of prelamin A, there is an additional farnesylation-dependent endoproteolysis, which is defective in two congenital diseases: Hutchinson-Gilford progeria (HGPS) and restrictive dermopathy (RD). These two diseases arise respectively from defects in the prelamin A substrate and the enzyme (ZmpSte24) that processes it. Recent work has shed light on the roles of the lamin proteins and the enzymes involved in their farnesylation-dependent maturation. Other experimental work, including mouse model studies, have examined the possibility …
Dna Damage Responses In Progeroid Syndromes Arise From Defective Maturation Of Prelamin A, Michael Sinensky, Y. Liu, A. Rusinol, Y. Wang, Y. Zou
Dna Damage Responses In Progeroid Syndromes Arise From Defective Maturation Of Prelamin A, Michael Sinensky, Y. Liu, A. Rusinol, Y. Wang, Y. Zou
Faculty Publications, Biological Sciences
The genetic diseases Hutchinson-Gilford progeria syndrome (HGPS) and restrictive dermopathy (RD) arise from accumulation of farnesylated prelamin A because of defects in the lamin A maturation pathway. Both of these diseases exhibit symptoms that can be viewed as accelerated aging. The mechanism by which accumulation of farnesylated prelamin A leads to these accelerated aging phenotypes is not understood. Here we present evidence that in HGPS and RD fibroblasts, DNA damage checkpoints are persistently activated because of the compromise in genomic integrity. Inactivation of checkpoint kinases Ataxia-telangiectasia-mutated (ATM) and ATR (ATM- and Rad3-related) in these patient cells can partially overcome their …
Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz
Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz
Faculty Publications, Chemistry
Absorption, emission, and excitation spectra for solid-state and solution of Tb(III), Dy(III), and Gd(III) complexes with the polypyridine ligand 6,6‘-bis[bis(2-pyridylmethyl)-aminomethyl]-2,2‘-bipyridine (C36H34N8) are presented. Measurements of excited-state lifetimes and quantum yields in various solvents at room temperature and 77 K are also reported and used to characterize the excited-state energetics of this system. Special attention is given to the characterization of metal-to-ligand energy transfer efficiency and mechanisms. The measurement of circularly polarized luminescence (CPL) from the solution of the Dy(III) complex following circularly polarized excitation confirms the chiral structure of the complexes under study. No CPL is present in the luminescence …
Reduced Macrophage Apoptosis Is Associated With Accelerated Atherosclerosis In Low-Denstiy Lipoprotein Receptor-Null Mice, Michael Sinensky, J. Liu, D. P. Thweke, Y. R. Su, M. F. Linton, S. Fazio
Reduced Macrophage Apoptosis Is Associated With Accelerated Atherosclerosis In Low-Denstiy Lipoprotein Receptor-Null Mice, Michael Sinensky, J. Liu, D. P. Thweke, Y. R. Su, M. F. Linton, S. Fazio
Faculty Publications, Biological Sciences
Objective— The majority of apoptotic cells in atherosclerotic lesions are macrophages. However, the pathogenic role of macrophage apoptosis in the development of atherosclerosis remains unclear. Elevated expression of Bax, one of the pivotal proapoptotic proteins of the Bcl-2 family, has been found in human atherosclerotic plaques. Activation of Bax also occurs in free cholesterol-loaded and oxysterol-treated mouse macrophages. In this study, we examined the effect of Bax deficiency in bone marrow-derived leukocytes on the development of atherosclerosis in low-density lipoprotein receptor-null (LDLR−/−) mice. Methods and Results— Fourteen 8-week-old male LDLR−/− mice were lethally irradiated and reconstituted with either wild-type (WT) …
Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz
Characterization Of The Electronic Excited-State Energetics And Solution Structure Of Lanthanide(Iii) Complexes With The Polypyridine Ligand 6,6'-Bis[Bis(2-Pyridylmethyl)Aminomethyl]-2,2'-Bipyridine, Gilles Muller, P. Gawryszewska, J. Sokolnicki, A. Dossing, J. P. Riehl, J. Legendziewicz
Gilles Muller
Absorption, emission, and excitation spectra for solid-state and solution of Tb(III), Dy(III), and Gd(III) complexes with the polypyridine ligand 6,6‘-bis[bis(2-pyridylmethyl)-aminomethyl]-2,2‘-bipyridine (C36H34N8) are presented. Measurements of excited-state lifetimes and quantum yields in various solvents at room temperature and 77 K are also reported and used to characterize the excited-state energetics of this system. Special attention is given to the characterization of metal-to-ligand energy transfer efficiency and mechanisms. The measurement of circularly polarized luminescence (CPL) from the solution of the Dy(III) complex following circularly polarized excitation confirms the chiral structure of the complexes under study. No CPL is present in the luminescence …
Lanthanide Spectroscopic Studies Of The Dinuclear And Mg(Ii)-Dependent Pvuii Restriction Endonuclease, Gilles Muller, L. M. Bowen, J. P. Riehl, C. M. Dupureur
Lanthanide Spectroscopic Studies Of The Dinuclear And Mg(Ii)-Dependent Pvuii Restriction Endonuclease, Gilles Muller, L. M. Bowen, J. P. Riehl, C. M. Dupureur
Faculty Publications, Chemistry
Type II restriction enzymes are homodimeric systems that bind four to eight base pair palindromic recognition sequences of DNA and catalyze metal ion-dependent phosphodiester cleavage. While Mg(II) is required for cleavage in these enzymes, in some systems Ca(II) promotes avid substrate binding and sequence discrimination. These properties make them useful model systems for understanding the roles of alkaline earth metal ions in nucleic acid processing. We have previously shown that two Ca(II) ions stimulate DNA binding by PvuII endonuclease and that the trivalent lanthanide ions Tb(III) and Eu(III) support subnanomolar DNA binding in this system. Here we capitalize on this …
Lanthanide Spectroscopic Studies Of The Dinuclear And Mg(Ii)-Dependent Pvuii Restriction Endonuclease, Gilles Muller, L. M. Bowen, J. P. Riehl, C. M. Dupureur
Lanthanide Spectroscopic Studies Of The Dinuclear And Mg(Ii)-Dependent Pvuii Restriction Endonuclease, Gilles Muller, L. M. Bowen, J. P. Riehl, C. M. Dupureur
Gilles Muller
Type II restriction enzymes are homodimeric systems that bind four to eight base pair palindromic recognition sequences of DNA and catalyze metal ion-dependent phosphodiester cleavage. While Mg(II) is required for cleavage in these enzymes, in some systems Ca(II) promotes avid substrate binding and sequence discrimination. These properties make them useful model systems for understanding the roles of alkaline earth metal ions in nucleic acid processing. We have previously shown that two Ca(II) ions stimulate DNA binding by PvuII endonuclease and that the trivalent lanthanide ions Tb(III) and Eu(III) support subnanomolar DNA binding in this system. Here we capitalize on this …
Temperature And Pressure Dependence Of Excitation Spectra As A Probe Of The Solution Structure And Equilibrium Thermodynamics Of A Eu(Iii) Complex Containing A Modified Dota Ligand, Gilles Muller, S. D. Kean, D. Parker, J. P. Riehl
Temperature And Pressure Dependence Of Excitation Spectra As A Probe Of The Solution Structure And Equilibrium Thermodynamics Of A Eu(Iii) Complex Containing A Modified Dota Ligand, Gilles Muller, S. D. Kean, D. Parker, J. P. Riehl
Faculty Publications, Chemistry
No abstract provided.
Temperature And Pressure Dependence Of Excitation Spectra As A Probe Of The Solution Structure And Equilibrium Thermodynamics Of A Eu(Iii) Complex Containing A Modified Dota Ligand, Gilles Muller, S. D. Kean, D. Parker, J. P. Riehl
Temperature And Pressure Dependence Of Excitation Spectra As A Probe Of The Solution Structure And Equilibrium Thermodynamics Of A Eu(Iii) Complex Containing A Modified Dota Ligand, Gilles Muller, S. D. Kean, D. Parker, J. P. Riehl
Gilles Muller
No abstract provided.
Radicals, Metals And Magnetism, David J R Brook
Radicals, Metals And Magnetism, David J R Brook
Faculty Publications
The interaction between unpaired electrons governs many physical properties of materials. Although in a fundamental sense the interaction is simple, a full understanding of the interaction in molecular systems is complicated by the presence of other bonding and non-bonding electrons. The resulting many body problem is very challenging. Nevertheless, much qualitative understanding can be obtained from applying simple molecular orbital theory and considering only the partly filled orbitals. The resulting model can be used to describe existing diradical and metal-radical systems and also has predicative value in the search for molecular magnets and design of nanoscale devices.
Radicals, Metals And Magnetism, David J R Brook
Radicals, Metals And Magnetism, David J R Brook
Faculty Publications, Chemistry
The interaction between unpaired electrons governs many physical properties of materials. Although in a fundamental sense the interaction is simple, a full understanding of the interaction in molecular systems is complicated by the presence of other bonding and non-bonding electrons. The resulting many body problem is very challenging. Nevertheless, much qualitative understanding can be obtained from applying simple molecular orbital theory and considering only the partly filled orbitals. The resulting model can be used to describe existing diradical and metal-radical systems and also has predicative value in the search for molecular magnets and design of nanoscale devices.
Radicals, Metals And Magnetism, David J R Brook
Radicals, Metals And Magnetism, David J R Brook
David J. R. Brook
The interaction between unpaired electrons governs many physical properties of materials. Although in a fundamental sense the interaction is simple, a full understanding of the interaction in molecular systems is complicated by the presence of other bonding and non-bonding electrons. The resulting many body problem is very challenging. Nevertheless, much qualitative understanding can be obtained from applying simple molecular orbital theory and considering only the partly filled orbitals. The resulting model can be used to describe existing diradical and metal-radical systems and also has predicative value in the search for molecular magnets and design of nanoscale devices.
The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton
The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton
Faculty Publications, Biological Sciences
The conversion of mammalian prelamin A to mature lamin A proceeds through the removal of 18 amino acids from the carboxyl terminus. The initial step in this processing is the isoprenylation of a CAAX box cysteine. This proteolytic event is distinctive for prelamin A among the known prenylated mammalian proteins. Since the carboxyl terminus of prelamin A is removed during maturation, it is not obvious that this protein would undergo the two reactions subsequent to prenylation observed in other CAAX box proteins-the endoproteolytic removal of the carboxyl-terminal 3 amino acids and the subsequent methylation of the now carboxyl-terminal cysteine. To …
Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle
Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle
Faculty Publications, Biological Sciences
No abstract provided.
Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick
Isoprenylation Is Required For The Processing Of The Lamin A Precursor, Michael Sinensky, L. A. Beck, T. J. Hosick
Faculty Publications, Biological Sciences
The nuclear lamina proteins, prelamin A, lamin B, and a 70-kD lamina-associated protein, are posttranslationally modified by a metabolite derived from mevalonate. This modification can be inhibited by treatment with (3-R,S)-3-fluoromevalonate, demonstrating that it is isoprenoid in nature. We have examined the association between isoprenoid metabolism and processing of the lamin A precursor in human and hamster cells. Inhibition of 3-hydroxy-3-methylglutaryl coenzyme A reductase by mevinolin (lovastatin) specifically depletes endogenous isoprenoid pools and inhibits the conversion of prelamin A to lamin A. Prelamin A processing is also blocked by mevalonate starvation of Mev-1, a CHO cell line auxotrophic for mevalonate. …
Incorporation Of A Product Of Mevalonic Acid Metabolism Into Proteins Of Chinese Hamster Ovary Nuclei, Michael Sinensky, L. A. Beck, T. Hosick
Incorporation Of A Product Of Mevalonic Acid Metabolism Into Proteins Of Chinese Hamster Ovary Nuclei, Michael Sinensky, L. A. Beck, T. Hosick
Faculty Publications, Biological Sciences
We have examined the nuclear localization of isoprenylated proteins in CHO-K1 cells labeled with [14C]mevalonate. Nuclear proteins of 68, 70, and 74 kD, posttranslationally modified by an isoprenoid, are also components of a nuclear matrix-intermediate filament preparation from CHO cells. Furthermore, the 68-, 70-, and 74-kD isoprenylated polypeptides are immunoprecipitated from cell extracts with two different anti-lamin antisera. Based on exact two-dimensional comigration with lamin B, both from rat liver lamin and CHO nuclear matrix-intermediate filament preparations, and its immunoprecipitation with anti-lamin antisera, we conclude that the 68-kD isoprenylated protein found in nuclei from [14C]mevalonate-labeled CHO cells is lamin B. …
Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky
Adaptative Alteration In Phospholipid Composition Of Plasma Membranes From A Somatic Cell Mutant Defective In The Regulation Of Cholesterol Biosynthesis, Michael Sinensky
Faculty Publications, Biological Sciences
A somatic cell mutant (CR1) of a Chinese hamster ovary cell (CHO-K1) which has previously been shown to be defective in the regulation of cholesterol biosynthesis accumulates more cholesterol than the parental cell line in plasma membranes. Although such an increase in membrane cholesterol should lead to an increase in the order parameter of these membranes, as measured with an electron spin resonance spin probe, the order parameters of mutant and wild-type plasma membranes are identical--apparently because of an adaptive alteration in membrane phospholipid composition. The phospholipid compositions of mutant and wild-type cell plasma membranes are compared and the mutant …