Search results for "Ligand binding"
showing 10 items of 16 documents
Characterization of the Heme Pocket Structure and ligand binding kinetics of non-symbiotic hemoglobins from the model legume Lotus japonicus
2017
14 Pags.- 6 Figs. This article is part of the Research Topic: Advances in legume research ( http://journal.frontiersin.org/researchtopic/4288/advances-in-legume-research ). Copyright of the Authors through a Creative Commons Attribution License. This Document is Protected by copyright and was first published by Frontiers. All rights reserved. it is reproduced with permission.
Biophysical and functional characterization of the human olfactory receptor OR1A1 expressed in a mammalian inducible cell line
2014
International audience; Olfactory receptors (ORs) play a crucial role in detecting the odorant molecules present in the surrounding environment. These receptors, which belong to class A G-protein-coupled receptors, constitute the largest transmembrane protein family in the human genome. Functional studies showed that the OR family includes members that are able to respond to a large set of odorants and members that are activated by a relatively small number of related odorants. To understand the molecular mechanisms that govern the receptor-ligand interactions, we overexpressed the human OR hOR1A1 in a stable tetracycline-inducible HEK293S cell line. This receptor was engineered by insertin…
Histidine tracts in human transcription factors: insight into metal ion coordination ability
2017
Consecutive histidine repeats are chosen both by nature and by molecular biologists due to their high affinity towards metal ions. Screening of the human genome showed that transcription factors are extremely rich in His tracts. In this work, we examine two of such His-rich regions from forkhead box and MAFA proteins—MB3 (contains 18 His) and MB6 (with 21 His residues), focusing on the affinity and binding modes of Cu2+ and Zn2+ towards the two His-rich regions. In the case of Zn2+ species, the availability of imidazole nitrogen donors enhances metal complex stability. Interestingly, an opposite tendency is observed for Cu2+ complexes at above physiological pH, in which amide nitrogens part…
Autoradiographic imaging of altered synaptic αβγ2 and extrasynaptic αβ GABAA receptors in a genetic mouse model of anxiety
2004
Abstract To image the possible alterations in brain regional GABAA receptor subtype properties in a genetic animal model of human anxiety, mice heterozygous for the deletion of GABAA receptor γ2 subunit (γ2+/−) were studied using ligand autoradiographic assays on brain cryostat sections. The [ 35 S ]TBPS binding assay was designed to reveal impaired GABA and channel site coupling shown to be more prominent in recombinant α1/6β3 than in α1/2β3γ2 or β2 subunit-containing GABAA receptors expressed in HEK 293 cells. Increased GABA-insensitive [ 35 S ]TBPS binding in the γ2+/− mouse brains was evident in the cerebral cortex and in subcortical regions, the alterations being regionally similar to …
DMAP-BODIPY Alkynes: A Convenient Tool for Labeling Biomolecules for Bimodal PET-Optical Imaging
2014
Several new boron dipyrromethene/N,N-dimethylaminopyridine (BODIPY-DMAP) assemblies were synthesized as precursors for bimodal imaging probes (optical imaging, OI/positron emission tomography, PET). The photophysical properties of the new compounds were also studied. The first proof-of-concept was obtained with the preparation of several new BODIPY-labeled bombesins and evaluation of the affinity for bombesin receptors by using a competition binding assay. Fluorination reactions were investigated on DMAP-BODIPY precursors as well as on DMAP-BODIPY-labeled bombesins. Chemical modifications on the BODIPY core were also performed to obtain luminescent dyes emitting in the therapeutic window (6…
Evidence for the presence of autoantibodies to the collagen-like portion of C1q in systemic lupus erythematosus.
1988
We investigated the connection between the C1q solid-phase binding assay (C1q SPBA) and double-stranded DNA antibodies, and analyzed the immune complex material in systemic lupus erythematosus (SLE) sera. Comparison with a new monoclonal assay for C1q-bearing immune complexes (the 242G3 assay) revealed that the immune complexes in SLE bind specifically to solid-phase C1q, and not to fluid-phase C1q. The C1q solid-phase binding activity sedimented as 7S IgG, was insensitive to DNase treatment, and could be selectively absorbed by C1q-coupled beads and by bovine serum albumin-anti-bovine serum albumin C1q beads, but not by DNA. Thus, antibodies to double-stranded DNA do not interfere in the C…
Comparison of a Novel Homogeneous Cyclic Amp Assay and a Luciferase Assay for Measuring Stimulating Thyrotropin-Receptor Autoantibodies.
2019
Objective: Stimulating thyrotropin-receptor antibodies (TSAb) cause Graves’ disease (GD). We tested a novel homogeneous fluorescent 3′,5′ cyclic adenine monophosphate (cAMP) assay for the detection of TSAb in a bioassay. Methods: Chinese hamster ovary (CHO) cell lines expressing either a chimeric (MC4) or wild-type (WT) TSH-R were incubated with the adenyl cyclase activator forskolin, a human TSAb monoclonal antibody (M22), and with sera from GD patients. Intracellular cAMP levels were measured using a Bridge-It® cAMP assay, and the results were compared with a luciferase-based bioassay. Results: Both cell lines were stimulated with forskolin concentrations (0.006–200 µM) in a dose-dependen…
The inorganic polymer, polyphosphate, blocks binding of SARS-CoV-2 spike protein to ACE2 receptor at physiological concentrations
2020
Graphical abstract The inorganic physiological polymer, polyphosphate, blocks binding of SARS-CoV-2 spike protein to ACE2 receptor at physiological concentrations. This discovery proposes polyphosphate as a new member of the host's antiviral innate immune defense.
Comparative histological, histochemical, immunohistochemical and biochemical studies on oestrogen receptors, lectin receptors, and Barr bodies in hum…
1986
The present study performed on a total of 567 cases of human female breast cancer compares the results of the biochemical assay (dextran-coated charcoal assay = DCC) for oestrogen receptor (ER) with those of several morphological methods developed for the detection of the ER or for the prediction of prognosis by use of other systems (FSA = fluorescent ligand binding assay, ER-ICA = monoclonal antibody assay for ER, LRA = lectin receptor assay using peanut agglutinin, and Barr body estimation). Whereas no correlation at all was observed among the results of the DCC and those of the FSA and Barr body estimation, the ER-ICA and the LRA showed an unanimous tendency towards higher values of ER w…
Research Letter: Structural Combination of Established 5-HT2A Receptor Ligands: New Aspects of the Binding Mode
2010
MH.MZ, MDL 100907, and altanserin are structurally similar 4-benzoyl-piperidine derivatives and are well accommodated to receptor interaction models. We combined structural elements of different high-affinity and selective 5-HT(2A) antagonists, as MH.MZ, altanserin, and SR 46349B, to improve the binding properties of new compounds. Three new derivatives were synthesized with a 4-benzoyl-piperidine moiety as the lead structure. The in vitro affinity of the novel compounds was determined by a [³H]MDL 100907 competition binding assay. The combination of MH.MZ and SR 46349B resulted in a compound (8) with a moderate affinity toward the 5-HT(2A) receptor (K(i) = 57 nm). The remarkably reduced af…