Search results for "binding"
showing 10 items of 3896 documents
Age-dependent regulation of antioxidant genes by p38α MAPK in the liver
2018
p38α is a redox sensitive MAPK activated by pro-inflammatory cytokines and environmental, genotoxic and endoplasmic reticulum stresses. The aim of this work was to assess whether p38α controls the antioxidant defense in the liver, and if so, to elucidate the mechanism(s) involved and the age-related changes. For this purpose, we used liver-specific p38α-deficient mice at two different ages: young-mice (4 months-old) and old-mice (24 months-old). The liver of young p38α knock-out mice exhibited a decrease in GSH levels and an increase in GSSG/GSH ratio and malondialdehyde levels. However, old mice deficient in p38α had higher hepatic GSH levels and lower GSSG/GSH ratio than young p38α knock-…
High-precision mass measurements and production of neutron-deficient isotopes using heavy-ion beams at IGISOL
2019
An upgraded ion-guide system for the production of neutron-deficient isotopes with heavy-ion beams has been commissioned at the IGISOL facility with an $^{36}\mathrm{Ar}$ beam on a $^{\mathrm{nat}}\mathrm{Ni}$ target. It was used together with the JYFLTRAP double Penning trap to measure the masses of $^{82}\mathrm{Zr}, ^{84}\mathrm{Nb}, ^{86}\mathrm{Mo}, ^{88}\mathrm{Tc}$, and $^{89}\mathrm{Ru}$ ground states and the isomeric state $^{88}\mathrm{Tc}^{m}$. Of these, $^{89}\mathrm{Ru}$ and $^{88}\mathrm{Tc}^{m}$ were measured for the first time. The precision of measurements of $^{82}\mathrm{Zr}, ^{84}\mathrm{Nb}$, and $^{88}\mathrm{Tc}$ was significantly improved. The literature value for $^…
Mollwo–Ivey relations for optical absorption bands of the atomic and F′ centres in alkali halides
2001
Evidence indicates that two classes of the transient IR-absorption bands: (a) with maxima at 0.27-0.36 eV in NaCI, KCI, KBr, KI and RbCl and due to shallow electron traps or bound polarons according to Jacobs (Phys. Stat. Sol. B 129 (1985) 755) and Korovkin and Lebedkina (Fiz. Tverd. Tela (Russian) 35 (1993) 642), and (b) with maxima at 0.15-0.36 eV in NaI, NaBr, NaCl : I, KCl : I I, RbCl: I and RbBr : I, due to on-centre STE localised at iodine-dimer according to Hirota et al. (J. Phys. Soc. Japan 63 (1994) 2774, Phys. Rev. B 52 (1995) 7779) and Edamatsu and Hirai (Mater. Sci. Forum 239-241 (1997) 525), are caused by the same defect. We propose that the defect is an atomic alkali impurity …
Adsorption of atomic and molecular oxygen on the SrTiO3(001) surfaces: Computer simulations by means of hybrid density functional calculations and ab…
2005
AbstractAb initio calculations based on density functional theory (DFT) have been used to study the energetics, fully relaxed structure, charge redistribution, and electronic density of states of adsorbed atomic and molecular oxygen on defectless unreconstructed SrO- and TiO2-terminated SrTiO3(001) surfaces. Exchange-correlation functional applied within DFT contains a “hybrid” of the non-local Hartree–Fock exchange, DFT exchange, and generalized gradient approximation correlation functionals. The calculations are performed on periodically repeated systems (two-dimensional slabs) large enough for the adsorbed species to be treated as isolated. We find substantial binding energies of up to 1…
Species- and Subtype-Specific Recognition by Antibody WF6 of a Sequence Segment Forming an α-Bungarotoxin Binding Site on the Nicotinic Acetylcholine…
1992
The monoclonal antibody WF6 competes with acetylcholine and alpha-bungarotoxin (alpha-BGT) for binding to the Torpedo nicotinic acetylcholine receptor (nAChR) alpha 1 subunit. Using synthetic peptides corresponding to the complete Torpedo nAChR alpha 1 subunit, we previously mapped a continuous epitope recognized by WF6, and the prototope for alpha-BGT, to the sequence segment alpha 1(181-200). Single amino acid substitution analogs have been used as an initial approach to determine the critical amino acids for WF6 and alpha-BGT binding. In the present study, we continue our analysis of the structural features of the WF6 epitope by comparing its cross-reactivity with synthetic peptides corr…
α1-Adrenoceptors in the rat cerebral cortex: New insights into the characterization of α1L- and α1D-adrenoceptors
2010
36 p., figuras y tablas, bibliografía
Studien zum Vorgang der Wasserstoffübertragung, 39. Langlebige Hydrierkatalysatoren durch kovalente Verknüpfung von Phosphin-Rhodium-Komplexen an Aer…
1976
Homogene Phosphin-Rhodium-Katalysatoren werden durch kovalente Bindung an ‘Aminoaerosil’ heterogenisiert. Die Abhangigkeit der Hydriergeschwindigkeit von der Entfernung der aktiven Zentren zur Oberflache, von der Temperatur, vom Losungsmittel und von der Struktur der eingesetzten Olefine wird untersucht. Studies on the Occurrence of Hydrogen Transfer, 39. — Long-Lived Hydrogenation Catalyst by Covalent Fixation of Phosphine-Rhodium-Complexes on the Surface of Aerosil 200 The covalent binding of hitherto homogeneous phosphine-rhodium catalysts to “Amino-aerosil” is described. The dependence of the rate of catalysed hydrogenation upon the distance between the reaction centre and the silica su…
Unveiling the reaction mechanism of novel copper N-alkylated tetra-azacyclophanes with outstanding superoxide dismutase activity.
2020
Quantum chemical and multiscale calculations reveal the mechanistic pathway of two superoxide dismutase mimetic N-alkylated tetra-azacyclophane copper complexes with remarkable activity. The arrangement of the binding site afforded by the bulky alkyl substituents and the coordinated water molecule as a proton source play key roles in the reaction mechanism.
Computational simulations on the binding and reactivity of a nitrile inhibitor of the SARS-CoV-2 main protease.
2021
We present a detailed computational analysis of the binding mode and reactivity of the novel oral inhibitor PF-07321332 developed against the SARS-CoV-2 3CL protease. Alchemical free energy calculations suggest that positions P3 and P4 could be susceptible to improvement in order to get a larger binding strength. QM/MM simulations unveil the reaction mechanism for covalent inhibition, showing that the nitrile warhead facilitates the recruitment of a water molecule for the proton transfer step.
Analysis of the Decarboxylation Step in Mammalian Histidine Decarboxylase
2008
We report a hybrid quantum mechanics/molecular mechanics theoretical study on the reaction mechanism of mammalian histidine decarboxylase that allows us to obtain valuable insights on the structure of the cofactor-substrate adduct (external aldimine) in the active site of rat histidine decarboxylase. By means of molecular dynamics simulations, we traced the potential of mean force corresponding to the decarboxylation reaction of the adduct both in the active site of the enzyme and in aqueous solution. By comparing this process in both media, we have identified the key electrostatic interactions that explain the lowering of the free energy barrier in the enzyme. Our analysis also offers a va…