Search results for "Affinities"
showing 10 items of 62 documents
<p class="HeadingRunIn"><strong>Reinterpretation of the enigmatic Ordovician genus <em>Bolboporites </em>(Echinodermata)</…
2019
Bolboporites is an enigmatic Ordovician cone-shaped fossil, the precise nature and systematic affinities of which have been controversial over almost two centuries. For the first time, a wide range of techniques (CT-scan, SEM, cathodoluminescence, XPL, UV epifluorescence, EBSD, FT-IR and XRF spectrometry) were applied to well-preserved specimens of Bolboporites from Norway and Russia. Our main finding confirms its echinoderm affinities, as shown by its stereomic microstructure and by the first definitive evidence of its monocrystalline nature. Each cone consists in a single, microporous calcitic crystal with a narrow longitudinal internal canal. These results are combined with all previous …
Addressing selectivity criteria in binding equilibria
2012
Abstract Chemical systems, in particular those involving biological and environmental backgrounds, develop through selective processes which are determined by multiple equilibria. Several methods that have been developed to assess thermodynamic selectivity in binding equilibria, including the analysis of selectivity coefficients, the use of calculated species distribution diagrams, selectivity diagrams, and conditional stability constants, are reviewed in this paper with reference to examples mainly related to chemical systems of biological and/or environmental concern. Also the concept of binding affinity has been dealt with, since binding selectivity in equilibrium systems relates to the …
A new genus of Phaneropterinae (Orthoptera: Ensifera: Tettigoniidae) from Central Africa.
2014
The new genus Pseudoplangia is described for Plangia laminifera Karsch, 1896. Its general aspect is similar to that of the genus Plangia Stål, 1873, but it differs remarkably in the vertex width, in the shape of eyes, that are oval and elongate, in the length of mid femora, that are shorter than pronotum length, in the shape of fore and mid legs that are very much laterally compressed, and in the presence of broad-based spines on the hind tibiae.
Beta-carbolines as benzodiazepine receptor ligands II: Synthesis and benzodiazepine receptor affinity of beta-carboline-3-carboxylic acid amides.
1985
Numerous beta-carboline-3-carboxamides were synthesized by amidation of beta-carboline-3-carboxylic acid, with various amino acids and amino acid esters serving as amine components, and tested in respect to their affinity for the benzodiazepine receptor in mouse brain membranes. The title compounds have affinities in the low micromolar range. The results are discussed with respect to their relevance for a possible beta-carboline structure containing the endogenous ligand of the benzodiazepine receptor.
Layered Thiadiazoloquinoxaline-Containing Long Pyrene-Fused N-Heteroacenes
2018
Three thiadiazoloquinoxaline-containing long pyrene-fused N-heteroacenes with 8, 13, and 18 rings were designed and synthesized. They show high electron affinities (EAs) of approximately 4.1 eV, which were derived from the onset of the reduction peaks in cyclic voltammetry. Crystal structure analysis revealed in-plane extension through close contacts between thiadiazole units as well as layered packing, enabling in-plane and interlayer electron transport. Organic field-effect transistor devices provided electron mobilities, which suggest a potential way to enhance the charge transport in long N-heteroacenes.
Stronger host-guest binding does not necessarily give brighter particles: a case study on polymeric AIEE-tunable and size-tunable supraspheres.
2018
Supraspheres were prepared from a pillar[5]arene-based linear polymer (the host) and several multitopic guests. According to host-guest binding studies in nanosystems, the optical and structural properties (fluorescence capability, density, and particle size) of the nanoparticles were correlated not with the host-guest binding affinities, but with the relative fluorescence quantum yield.
Targeting Cavity-Creating p53 Cancer Mutations with Small-Molecule Stabilizers: the Y220X Paradigm
2020
We have previously shown that the thermolabile, cavity-creating p53 cancer mutant Y220C can be reactivated by small-molecule stabilizers. In our ongoing efforts to unearth druggable variants of the p53 mutome, we have now analyzed the effects of other cancer-associated mutations at codon 220 on the structure, stability, and dynamics of the p53 DNA-binding domain (DBD). We found that the oncogenic Y220H, Y220N, and Y220S mutations are also highly destabilizing, suggesting that they are largely unfolded under physiological conditions. A high-resolution crystal structure of the Y220S mutant DBD revealed a mutation-induced surface crevice similar to that of Y220C, whereas the corresponding pock…
Modulation of DNA binding by reversible metal-controlled molecular reorganizations of scorpiand-like ligands.
2012
DNA interaction with scorpiand azamacrocycles has been achieved through modulation of their binding affinities. Studies performed with different experimental techniques provided evidence that pH or metal-driven molecular reorganizations of these ligands regulate their ability to interact with calf thymus DNA (ctDNA) through an intercalative mode. Interestingly enough, metal-driven molecular reorganizations serve to increase or decrease the biological activities of these compounds significantly.
Template-Assembled Synthetic G-Quadruplex (TASQ): A Useful System for Investigating the Interactions of Ligands with Constrained Quadruplex Topologies
2010
A new biomolecular device for investigating the interactions of ligands with constrained DNA quadruplex topologies, using surface plasmon resonance (SPR), is reported. Biomolecular systems containing an intermolecular-like G-quadruplex motif 1 (parallel G-quadruplex conformation), an intramolecular G-quadruplex 2, and a duplex DNA 3 have been designed and developed. The method is based on the concept of template-assembled synthetic G-quadruplex (TASQ), whereby quadruplex DNA structures are assembled on a template that allows precise control of the parallel G-quadruplex conformation. Various known G-quadruplex ligands have been used to investigate the affinities of ligands for intermolecular…
Synthesis of site-heterologous haptens for high-affinity anti-pyraclostrobin antibody generation.
2011
The design and synthesis of functional chemical derivatives of small organic molecules is usually a key step for the intricate production of a variety of bioconjugates. In this respect, the derivatization site at which the spacer arm is introduced in immunizing conjugates constitutes a highly critical parameter for the generation of high-affinity and selective antibodies. However, due to the usual complexity of the required synthetic procedures, the appropriate comparison of alternative tethering positions has often been neglected. In the present study, meticulous strategies were followed to prepare synthetic derivatives of pyraclostrobin with the same linkers located at diverse rationally-…