Search results for "binding"

Context-dependent Pax-5 repression of a PU.1/NF-κB regulated reporter gene in B lineage cells

2001

Enhancers located in the 3' end of the locus in part regulate immunoglobulin heavy chain (IgH) gene expression. One of these enhancers, HS 1,2, is developmentally regulated by DNA binding proteins like NF-kappaB, Pax-5 and the protein complex NF-alphaP in B lineage cells. Here we report that NF-alphaP is the ets protein PU.1. A glutathione-S-transferase (GST)-pulldown assay demonstrated that PU.1 can physically interact with NF-kappaB in solution. Experiments in COS cells showed that PU.1 and NF-kappaB (p50/c-Rel) can activate transcription of an enhancer linked reporter gene. The paired domain protein Pax-5 has previously been shown to repress enhancer-dependent transcription. Additional c…

The Sea Urchin sns Insulator Blocks CMV Enhancer following Integration in Human Cells

2001

Insulators are a new class of genetic elements that attenuate enhancer function directionally. Previously, we characterized in sea urchin a 265-bp-long insulator, termed sns. To test insulator activity following stable integration in human cells, we placed sns between the CMV enhancer and a tk promoter up-stream of a GFP transgene of plasmid or retroviral vectors. In contrast to controls, cells transfected or transduced with insulated constructs displayed a barely detectable fluorescence. Southern blot and PCR ruled out vector rearrangement following integration into host DNA; RNase protection confirmed the enhancer blocking activity. Finally, we demonstrate that two cis-acting sequences, p…

Casein kinase 2 inhibits HomolD-directed transcription by Rrn7 in Schizosaccharomyces pombe.

2014

In Schizosaccharomyces pombe, ribosomal protein gene (RPG) promoters contain a TATA analogue element called the HomolD box. The HomolD-binding protein Rrn7 forms a complex with the RNA polymerase II machinery. Despite the importance of ribosome biogenesis to cell survival, the mechanisms involved in the regulation of transcription of eukaryotic RPGs are unknown. In this study, we identified Rrn7 as a new substrate of the pleiotropic casein kinase 2 (CK2), which is a regulator of basal transcription. Recombinant Rrn7 from S. pombe, which is often used as a model organism for studying eukaryotic transcription, interacted with CK2 in vitro and in vivo. Furthermore, CK2-mediated phosphorylation…

Functional characterization of the enhancer blocking element of the sea urchin early histone gene cluster reveals insulator properties and three esse…

2000

Insulator elements can be functionally identified by their ability to shield promoters from regulators in a position-dependent manner or their ability to protect adjacent transgenes from position effects. We have previously reported the identification of a 265 bp sns DNA fragment at the 3' end of the sea urchin H2A early histone gene that blocked expression of a reporter gene in transgenic embryos when placed between the enhancer and the promoter. Here we show that sns interferes with enhancer-promoter interaction in a directional manner. When sns is placed between the H2A modulator and the inducible tet operator, the modulator is barred from interaction with the basal promoter. However, th…

Oligoamide Foldamers as Helical Chloride Receptors-the Influence of Electron-Withdrawing Substituents on Anion-Binding Interactions.

2019

The anion-binding properties of three closely related oligoamide foldamers were studied using NMR spectroscopy, isothermal titration calorimetry and mass spectrometry, as well as DFT calculations. The 1 H NMR spectra of the foldamers in [D6 ]acetone solution revealed partial preorganization by intramolecular hydrogen bonding, which creates a suitable cavity for anion binding. The limited size of the cavity, however, enabled efficient binding by the inner amide protons only for the chloride anion resulting in the formation of a thermodynamically stable 1:1 complex. All 1:1 chloride complexes displayed a significant favourable contribution of the entropy term. Most likely, this is due to the …

Solution and solid-state studies on the halide binding affinity of perfluorophenyl-armed uranyl–salophen receptors enhanced by anion–π Interactions

2016

The enhancement of the binding between halide anions and a Lewis acidic uranyl-salophen receptor has been achieved by the introduction of pendant electron- deficient arene units into the receptor skeleton. The association and the occurrence of the elusive anion-p interaction with halide anions (as tetrabutylammonium salts) have been demonstrated in solution and in the solid state, providing unambiguous evidence on the interplay of the concerted interactions responsible for the anion binding.

Lithium adsorption at prismatic graphite surfaces enhances interlayer cohesion

2013

Abstract We use density functional calculations to determine the binding sites and binding energies of Li + at graphene edges and prismatic graphite surfaces. Binding is favorable at bare and carbonyl terminated surfaces, but not favorable at hydrogen terminated surfaces. These findings have implications for the exfoliation of graphitic anodes in lithium-ion batteries that happens if solute and solvent co-intercalate. First, specific adsorption facilitates desolvation of Li + . Second, chemisorption lowers the surface energy by about 1 J m −2 prismatic surface area, and gives graphite additional stability against exfoliation. The results offer an explanation for experiments that consistentl…

Dynamics of the ligand-binding domains of ionotropic glutamate receptors

2010

Oxidative DNA cleavage mediated by a new unexpected [Pd(BAPP)][PdCl4] complex (BAPP = 1,4-bis(3-aminopropyl)piperazine): crystal structure, DNA bindi…

2022

A novel Pd(II) double complex, [Pd(BAPP)][PdCl4], containing the 1,4-bis(3-aminopropyl)piperazine (BAPP) ligand is investigated. X-ray crystallography of a single crystal confirmed the structure of the [Pd(BAPP)][PdCl4] complex. The spectroscopic behavior was also elucidated using elemental analysis, nuclear magnetic resonance and Fourier-transform infrared spectroscopy, and mass spectrometry. The antimicrobial susceptibility of the [Pd(BAPP)][PdCl4] complex against all tested microbial strains was lower than that of the BAPP ligand except for C. albicans. The cytotoxic impacts of the BAPP ligand and its [Pd(BAPP)][PdCl4] complex were evaluated in vitro for HepG2, CaCo-2 and MCF7 cell lines…

Polycationic Monomeric and Homodimeric Asymmetric Monomethine Cyanine Dyes with Hydroxypropyl Functionality—Strong Affinity Nucleic Acids Binders

2021

New analogs of the commercial asymmetric monomethine cyanine dyes thiazole orange (TO) and thiazole orange homodimer (TOTO) with hydroxypropyl functionality were synthesized and their properties in the presence of different nucleic acids were studied. The novel compounds showed strong, micromolar and submicromolar affinities to all examined DNA ds-polynucleotides and poly rA–poly rU. The compounds studied showed selectivity towards GC-DNA base pairs over AT-DNA, which included both binding affinity and a strong fluorescence response. CD titrations showed aggregation along the polynucleotide with well-defined supramolecular chirality. The single dipyridinium-bridged dimer showed intercalatio…