Search results for "MOLECULAR RECOGNITION"
showing 10 items of 112 documents
Bio-metal-organic frameworks for molecular recognition and sorbent extraction of hydrophilic vitamins followed by their determination using HPLC-UV
2020
A bio-metal-organic framework (bio-MOF) derived from the amino acid L-serine has been prepared in bulk form and evaluated as sorbent for the molecular recognition and extraction of B-vitamins. The functional pores of bio-MOF exhibit high amounts of hydroxyl groups jointly directing other supramolecular host-guest interactions thus providing the recognition of B-vitamins in fruit juices and energy drinks. Single-crystal X-ray diffraction studies reveal the specific B-vitamin binding sites and the existence of multiple hydrogen bonds between these target molecules and the framework. It offered unique snapshots to accomplish an efficient capture of these solutes in complex aqueous matrices. Fo…
Effect of Substituents on the Molecular Shapes of π-Basic Macrotricyclic Receptors
2010
Molecular recognition between receptor and substrate is optimized when these compounds show complementary shapes, sizes, and interacting moieties. A family of C3v-symmetric macrotricycles 1–4 is presented that incorporate resorcinol- and mesitylene-derived “walls” and “cap”, respectively. These compounds feature, in principle, a tetrahedral π-basic cavity. This paper reports the effect of substituents in the “walls” and the “cap” on the shapes of the macrotricycles in solution (1H NMR), the solid state (X-ray diffraction), and gas phase (calculations). Substitution of the lower position of the “walls” by Br (in 3) or MeS (in 4) has the same effect as ethyl substitution of the “cap” (in 2), …
Similarities and differences between crystal and enzyme environmental effects on the electron density of drug molecules
2021
Abstract The crystal interaction density is generally assumed to be a suitable measure of the polarization of a low‐molecular weight ligand inside an enzyme, but this approximation has seldomly been tested and has never been quantified before. In this study, we compare the crystal interaction density and the interaction electrostatic potential for a model compound of loxistatin acid (E64c) with those inside cathepsin B, in solution, and in vacuum. We apply QM/MM calculations and experimental quantum crystallography to show that the crystal interaction density is indeed very similar to the enzyme interaction density. Less than 0.1 e are shifted between these two environments in total. Howeve…
Weighting non-covalent forces in the molecular recognition of C60. Relevance of concave–convex complementarity
2008
The relative contributions of several weak intermolecular forces to the overall stability of the complexes formed between structurally related receptors and [60]fullerene are compared, revealing a discernible contribution from concave–convex complementarity. Viruela Martin, Pedro Manuel, Pedro.M.Viruela@uv.es ; Viruela Martin, Rafael, Rafael.Viruela@uv.es ; Orti Guillen, Enrique, Enrique.Orti@uv.es
Highly selective chemical sensing in a luminescent nanoporous magnet.
2012
Among the wide variety of properties of interest that a given material can exhibit, luminescence is attracting an increasing attention due to its potential application in optical devices for lighting equipment and optical storage, [ 1a − c] optical switching, [ 1d ,e] and sensing. [ 1f − i ] At this respect, many scientists, working in the multidisciplinary fi eld of the materials science, have directed their efforts to the obtention of luminescent materials with potential sensing applications. For instance, sensitive and selective detection of gas and vapor phase analytes can result specially interesting because of the variety of applications that can be found in many different fi elds. A …
Physics and biophysics of solvent induced forces: hydrophobic interactions and context-dependent hydration
1998
Solvent induced forces (SIFs) among solutes derive from solvent structural modification due to solutes, and consequent thermodynamic drive towards minimization of related free energy costs. The role of SIFs in biomolecular conformation and function is appreciated by observing that typical SIF values fall within the 20–200 pN interval, and that proteins are stable by only a few kcal mol–1 (1 kcal mol–1 corresponds to 70 pN A). Here we study SIFs, in systems of increasing complexity, using Molecular Dynamics (MD) simulations which give time- and space-resolved details on the biologically significant scale of single protein residues and sidechains. Of particular biological relevance among our …
Chloride, carboxylate and carbonate transport by ortho-phenylenediamine-based bisureas
2013
Highly potent but structurally simple transmembrane anion transporters are reported that function at receptor to lipid ratios as low as 1 : 1 000 000. The compounds, based on the simple ortho-phenylenediamine-based bisurea scaffold, have been studied for their ability to facilitate chloride/nitrate and chloride/bicarbonate antiport, and HCl symport processes using a combination of ion selective electrode and fluorescence techniques. In addition, the transmembrane transport of dicarboxylate anions (maleate and fumarate) by the compounds was examined. Molecular dynamics simulations showed that these compounds permeate the membrane more easily than other promising receptors corroborating the e…
Molecular recognition of nucleotides in water by scorpiand-type receptors based on nucleobase discrimination.
2014
Abstract: The detection of nucleotides is of crucial impor-tance because they are the basic building blocks of nucleicacids. Scorpiand-based polyamine receptors functionalizedwith pyridine or anthracene units are able to form stablecomplexes with nucleotides in water, based on coulombic,p–p stacking, and hydrogen-bonding interactions. This be-havior has been rationalized by means of an explorationwith NMR spectroscopy and DFT calculations. Binding con-stants were determined by potentiometry. Fluorescencespectroscopy studies have revealed the potential of these re-ceptors as sensors to effectively and selectively distinguishguanosine-5’-triphosphate (GTP) from adenosine-5’-triphos-phate (ATP…
Concise and modular synthesis of regioisomeric haptens for the production of high-affinity and stereoselective antibodies to the strobilurin azoxystr…
2011
The immune response to regioisomeric haptens of azoxystrobin with varied derivatization sites was studied. Based on the Sonogashira and Suzuki-Miyaura couplings and following a straightforward modular design, we have synthesized four haptens with the same linker anchored through C-C bonds and located at different sites of the molecule. The most stereoselective antibodies were produced from immunogens with the spacer arm at a distal position from the β-methoxyacrylate moiety characteristic of strobilurins. Moreover, we observed that assay cross-reactivity was reliant on the functionalization site of the competitor derivative. Finally, the antibody binding site was explored using synthetic ch…
Toward an understanding of the 1,3-dipolar cycloaddition between diphenylnitrone and a maleimide:bisamide complex. A DFT analysis of the reactivity o…
2007
Abstract The 1,3-dipolar cycloaddition between diphenylnitrone and a maleimide:bisamide complex has been studied using density functional theory (DFT) methods at the B3LYP/6-31G∗ level. The molecular recognition of the bisamide receptor to maleimide favors the formation of the complex through three hydrogen bonds. However, they are not able to produce an efficient acceleration of the cycloaddition because the symmetric substitution of the dipolarophile sites. This poor capability is discussed in base of the transition state structures and the analysis of the reactivity indexes of the reagents.