Recognition Properties (recognition + property)

Distribution by Scientific Domains

Kinds of Recognition Properties

  • molecular recognition property


  • Selected Abstracts


    Methylazacalixpyridines: Remarkable Bridging Nitrogen-Tuned Conformations and Cavities with Unique Recognition Properties

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2006
    Han-Yuan Gong
    Abstract Methylazacalix[n]pyridines (n = 4, 8) and methylazacalix[m]arene[n]pyridines (m = n = 2, 4) have been synthesized by a convenient fragment coupling approach starting from 2,6-dibromopyridine, 2,6-diaminopyridine, and benzene-1,3-diamine. Thanks to the intrinsic electronic nature of nitrogen, which can adopt mainly sp2 hybridization, allowing it variously to conjugate, partially conjugate, or not conjugate with the adjacent one or two pyridine rings, the resulting nitrogen-bridged calixpyridine derivatives act as a unique class of macrocyclic host molecules with intriguing conformational structures offering fine-tunable cavities and versatile recognition properties. Whilst in solution it is fluxional, in the solid state methylazacalix[4]pyridine adopts a 1,3-alternate conformation with a C2v symmetry in which every two bridging nitrogen atoms conjugate with one pyridine ring. After protonation, the methylazacalix[4]pyridinium species has a different conjugation system of its four bridging nitrogen atoms, yielding the similar twisted 1,3-alternate conformations with an approximate S4 symmetry. The cavity of each protonated methylazacalix[4]pyridine, however, varies finely to accommodate guest species of different size and geometry, such as planar DMF or HO2CCO2, ion, a twisted HO2CCO2, ion, and a tetrahedral ClO4, ion. As giant macrocyclic hosts, both methylazacalix[8]pyridine and methylazacalix[4]arene[4]pyridine interact efficiently with fullerenes C60 and C70 through van der Waals forces. Their ease of preparation, versatile conformational structures, and recognition properties make these multinitrogen-containing calixarenes or cyclophanes unique and powerful macrocyclic hosts in supramolecular chemistry. [source]


    Study on the Anion Recognition Properties of Synthesized Receptors (III): Convenient Synthesis and Anion Recognition Property of Bisthiosemicarbazone Derivative

    CHINESE JOURNAL OF CHEMISTRY, Issue 10 2006
    You-Ming Zhang
    Abstract A new series of bisthiosemicarbazone derivative receptors (1, 2 and 3) have been synthesized by simple steps in good yields. Their anion recognition properties were studied by UV-Vis and 1H NMR spectroscopy. The result showed that the receptors 1, 2 and 3 all had a better selectivity to F,, CH3COO, and H2PO4,, but no evident binding with Cl,, Br,, I,, NO3, and HSO4,. Upon addition of the three anions to the receptors in DMSO, the solution acquired a color change from colorless to dark yellow that can be observed by the naked-eyes, thus the receptors can act as fluoride ion sensors even in the presence of other halide ions. The data showed that it was regular that the three receptors had different binding ability with the three anions. For the same anion, the association constants followed the trend: receptor 1>3>2. The UV-Vis data indicates that a 1:1 stoichiometry complex is formed through hydrogen bonding interactions between compound 1, 2 or 3 and anions. [source]


    Synthesis of Diamido Bridged Homooxacalix[3]arenes and Their Recognition Property for Linear Alkylammonium Ions

    CHINESE JOURNAL OF CHEMISTRY, Issue 12 2005
    Shi-Lan Liu
    Abstract The synthesis and conformation of di- O -bridged homooxacalix[3]arenes were reported. Their recognition ability towards alkylammonium ions was studied with the aid of NMR. Two of them show selective binding ability towards relatively longer linear alkylammonium ions (CH3(CH2)nNH3+, n=3,5). [source]


    Trans-species hair growth induction by human hair follicle dermal papillae

    EXPERIMENTAL DERMATOLOGY, Issue 4 2001
    C. A. B. Jahoda
    Abstract: A series of experimental bioassays has shown that the dermal papilla of the adult rodent vibrissa hair follicle retains unique inductive properties. In view of the many phenotypic and functional differences between specific hair follicle types, and the growing interest in hair follicle biology and disease, it remains important to establish that the human hair follicle dermal papilla has equivalent capabilities. In this study we tested the ability of human hair follicle papillae to induce hair growth when implanted into transected, athymic mouse vibrissa follicles. The implanted papillae that interacted with mouse follicle epithelium created new fibre-producing follicle end bulbs. The origin of the papillae in the recombinant structures was confirmed using laser capture microdissection and human specific gender determination by PCR. The demonstration that intact adult human dermal papillae can induce hair growth has implications for molecular analysis of basic hair growth mechanisms, particularly since the study involved common epithelial,mesenchymal signalling and recognition properties across species. It also improves the prospects for a cell-based clinical approach to hair follicle disorders. [source]


    Artificial neural network inversion of magnetotelluric data in terms of three-dimensional earth macroparameters

    GEOPHYSICAL JOURNAL INTERNATIONAL, Issue 1 2000
    Vjacheslav Spichak
    The possibility of solving the three-dimensional (3-D) inverse problem of geoelectrics using the artificial neural network (ANN) approach is investigated. The properties of a supervised ANN based on the back-propagation scheme with three layers of neurons are studied, and the ANN architecture is adjusted. A model class consisting of a dipping dyke in the basement of a two-layer earth with the dyke in contact with the overburden is used for numerical experiments. Six macroparameters of the 3-D model, namely the thickness of the top layer, which coincides with the depth of the dyke (D), the conductivity ratio between the first and second layers (C1,/C2,), the conductivity contrast of the dyke (C/C2,), and the width (W ), length (L ) and dip angle of the dyke (A), are used. Various groups of magnetotelluric field components and their transformations are studied in order to estimate the effect of the data type used on the ANN recognition ability. It is found that use of only the xy - and yx -components of impedance phases results in reasonable recognition errors for all unknown parameters (D: 0.02 per cent, C1/C2: 8.4 per cent, C/C2: 26.8 per cent, W : 0.02 per cent, L : 0.02 per cent, A: 0.24 per cent). The influence of the size and shape of the training data pool (including the ,gaps in education' and ,no target' effects) on the recognition properties is studied. Results from numerous ANN tests demonstrate that the ANN possesses good enough interpolation and extrapolation abilities if the training data pool contains a sufficient number of representative data sets. The effect of noise is estimated by means of mixing the synthetic data with 30, 50 and 100 per cent Gaussian noise. The unusual behaviour of the recognition errors for some of the model parameters when the data become more noisy (in particular, the fact that an increase in error is followed by a decrease) indicates that the use of standard techniques of noise reduction may give an opposite result, so the development of a special noise treatment methodology is required. Thus, it is shown that ANN-based recognition can be successfully used for inversion if the data correspond to the model class familiar to the ANN. No initial guess regarding the parameters of the 3-D target or 1-D layering is required. The ability of the ANN to teach itself using real geophysical (not only electromagnetic) data measured at a given location over a sufficiently long period means that there is the potential to use this approach for interpreting monitoring data. [source]


    Novel bioactive scaffolds with fibronectin recognition nanosites based on molecular imprinting technology

    JOURNAL OF APPLIED POLYMER SCIENCE, Issue 6 2010
    Elisabetta Rosellini
    Abstract Biomimetic materials for application in the field of tissue engineering are usually obtained through covalent bonding between the polymer backbone and the bioactive molecules. A totally new approach, proposed for the first time by our research group, for the creation of advanced synthetic support structures for cell adhesion and proliferation is represented by molecular imprinting (MI) technology. In this article, we describe the synthesis and characterization of molecularly imprinted polymers with recognition properties toward a fibronectin peptide sequence and their application as functionalization structures. Polymers, in the form of densely fused microgel particles, were obtained by precipitation polymerization. The imprinted particles showed good performance in terms of recognition capacity and quantitative rebinding; moreover, the epitope effect was observed, with the particles able to recognize and rebind not only the specific peptide sequence but also a larger fibronectin fragment. The cytotoxicity tests showed normal vitality in C2C12 myoblasts cultured in a medium that was put in contact with the imprinted particles. Therefore, imprinted particles were used to functionalize synthetic polymeric films by deposition on their surface. The deposition of the imprinted particles did not alter their specific recognition and rebinding behavior. The most remarkable result was obtained by the biological characterization: in fact, the functionalized materials appeared able to promote cell adhesion and proliferation. These results are very promising and suggest that MI can be used as an innovative functionalization technique to prepare bioactive scaffolds with an effective capacity for improving tissue regeneration. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 [source]


    Engineered 5S ribosomal RNAs displaying aptamers recognizing vascular endothelial growth factor and malachite green

    JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2009
    Xing Zhang
    Abstract In previous work, Vibrio proteolyticus 5S rRNA was shown to stabilize 13,50 nucleotide "guest" RNA sequences for expression in Escherichia coli. The expressed chimeric RNAs accumulated to high levels in E. coli without being incorporated into ribosomes and without obvious effects on the host cells. In this work, we inserted sequences encoding known aptamers recognizing a protein and an organic dye into the 5S rRNA carrier and showed that aptamer function is preserved in the chimeras. A surface plasmon resonance competitive binding assay demonstrated that a vascular endothelial growth factor (VEGF) aptamer/5S rRNA chimera produced in vitro by transcriptional runoff could compete with a DNA aptamer for VEGF, implying binding of the growth factor by the VEGF "ribosomal RNA aptamer." Separately, a 5S rRNA chimera displaying an aptamer known to increase the fluorescence of malachite green (MG) also enhanced MG fluorescence. Closely related control rRNA molecules showed neither activity. The MG aptamer/5S rRNA chimera, like the original MG aptamer, also increased the fluorescence of other triphenyl methane (TPM) dyes such as crystal violet, methyl violet, and brilliant green, although less effectively than with MG. These results indicate that the molecular recognition properties of aptamers are not lost when they are expressed in the context of a stable 5S rRNA carrier. Inclusion of the aptamer in a carrier may facilitate production of large quantities of RNA aptamers, and may open an approach to screening aptamer libraries in vivo. Copyright © 2009 John Wiley & Sons, Ltd. [source]


    Biological,synthetic hybrid block copolymers: Combining the best from two worlds

    JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2005
    Harm-Anton Klok
    Abstract Although biopolymers and synthetic polymers share many common features, each of these two classes of materials is also characterized by a distinct and very specific set of advantages and disadvantages. Combining biopolymer elements with synthetic polymers into a single macromolecular conjugate is an interesting strategy for synergetically merging the properties of the individual components and overcoming some of their limitations. This article focuses on a special class of biological,synthetic hybrids that are obtained by site-selective conjugation of a protein or peptide and a synthetic polymer. The first part of the article gives an overview of the different liquid-phase and solid-phase techniques that have been developed for the synthesis of well-defined, that is, site-selectively conjugated, synthetic polymer,protein hybrids. In the second part, the properties and potential applications of these materials are discussed. The conjugation of biological and synthetic macromolecules allows the modulation of protein binding and recognition properties and is a powerful strategy for mediating the self-assembly of synthetic polymers. Synthetic polymer,protein hybrids are already used as medicines and show significant promise for bioanalytical applications and bioseparations. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1,17, 2005 [source]


    Molecular imprinting of AMP by an ionic-noncovalent dual approach

    JOURNAL OF SEPARATION SCIENCE, JSS, Issue 19 2009
    Florent Breton
    Abstract In order to mimic recognition properties of adenylate kinase, molecularly imprinted polymers (MIPs) were prepared for adenosine 5,-monophosphate (AMP), a substrate of the enzyme. Different functional monomers interacting with the phosphate moiety were tested, and the MIP giving the best specific binding of AMP was composed with one equivalent of 2-(dimethylamino)ethyl methacrylate and ten equivalents of acrylamide compared to AMP. Packed into solid phase cartridge, this polymer showed similar characteristics than the enzyme, since it was specific for AMP toward other nucleotides. [source]


    Thermodynamic origin of the chiral recognition of tryptophan on teicoplanin and teicoplanin aglycone stationary phases

    JOURNAL OF SEPARATION SCIENCE, JSS, Issue 5 2005
    Mohamed Haroun
    Abstract The D-, L-tryptophan binding and the chiral recognition properties of the teicoplanin and teicoplanin aglycone (TAG) chiral stationary phase (CSPs) were compared at various column temperatures. The solute adsorption isotherms (bi-Langmuir model) were determined for both the two CSPs using the perturbation method. It was demonstrated that the sugar units were involved in the reduction of the apparent enantioselectivity through two phenomena: (i) the inhibition of some enantioselective contacts with low-affinity binding regions of the aglycone and (ii) a decrease in the stereoselective properties of the aglycone high-affinity binding pocket. The phenomenon (ii) was governed by both a decrease in the ratio of the enantiomer adsorption constant and a strong reduction of the site accessibility for D- and L-tryptophan. In addition, a temperature effect study was performed to investigate the chiral recognition mechanism at the aglycone high-affinity pocket. An enthalpy-entropy compensation analysis derived from the Grunwald model as well as the comparison with the literature data demonstrated that the enantioselective binding mode was dependent on an interface dehydration process. The change in the enantioselective process observed between the TAG and teicoplanin CSP was characterized by a difference of ca. 2,3 ordered water molecules released from the species interface. [source]


    Chiral Crystal Structure of Racemic Binaphthyl Poly(ether ketone) Macrocycles

    MACROMOLECULAR RAPID COMMUNICATIONS, Issue 7 2005
    Xing Wang
    Abstract Summary: The crystal structure of rigid, hollow, racemic binaphthyl poly(ether ketone) macrocycles has been elucidated by single crystal X-ray analysis. Multitudinal interactions were identified within the chiral space group P212121. The structural analysis revealed that this macrocyclic compound contains an elliptic chiral cavity with a size of 9.80,×,5.18 Å, which is similar to that of cyclodextrins. The knowledge about the interaction sites and the structure of the binaphthyl-based macrocycle provides a unique opportunity to understand its molecular or chiral recognition properties. Space-filling representation of the single (R)-macrocycle. [source]


    Single-molecule pair studies of the interactions of the ,-GalNAc (Tn-antigen) form of porcine submaxillary mucin with soybean agglutinin

    BIOPOLYMERS, Issue 9 2009
    Marit Sletmoen
    Abstract Mucins form a group of heavily O -glycosylated biologically important glycoproteins that are involved in a variety of biological functions, including modulating immune response, inflammation, and adhesion. Mucins are also involved in cancer and metastasis and often express diagnostic cancer antigens. Recently, a modified porcine submaxillary mucin (Tn-PSM) containing GalNAc,1- O -Ser/Thr residues was shown to bind to soybean agglutinin (SBA) with ,106 -fold enhanced affinity relative to GalNAc,1- O -Ser, the pancarcinoma carbohydrate antigen. In this study, dynamic force spectroscopy is used to investigate molecular pairs of SBA and Tn-PSM. A number of force jumps that demonstrate unbinding or rebinding events were observed up to a distance equal to 2.0 ,m, consistent with the length of the mucin chain. The unbinding force increased from 103 to 402 pN with increasing force loading rate. The position of the activation barrier in the energy landscape of the interaction was 0.1 nm. The lifetime of the SBA,TnPSM complex in the absence of applied force was determined to be in the range 1.3,1.9 s. Kinetic parameters describing the rate of dissociation of other sugar lectin interactions are in the range 3.3 × 10,3,2.5 × 10,3 s. The long lifetime of the SBA-TnPSM complex is compatible with a binding model in which lectin molecules "bind and jump" from ,-GalNAc residue to ,-GalNAc residue along the polypeptide chain of Tn-PSM before dissociating. These findings have important implications for the molecular recognition properties of mucins. © 2009 Wiley Periodicals, Inc. Biopolymers 91: 719,728, 2009. This article was originally published online as an accepted preprint. The "Published Online" date corresponds to the preprint version. You can request a copy of the preprint by emailing the Biopolymers editorial office at biopolymers@wiley.com [source]


    Reactive Sieving with Foldamers: Inspiration from Nature and Directions for the Future

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 9 2008
    Ronald
    Abstract Over the past several decades, chemists have designed a myriad of supramolecular scaffolds for the purpose of mimicking enzyme behavior and creating more advanced catalysts. Foldamers, one class of supramolecular structures that feature rapid, modular synthesis and dynamic structural properties and have been widely investigated for their molecular recognition properties. Specifically, our group has designed a reactive m -phenyleneethynylene foldamer, which mimics the selective properties ("reactive sieving") of the isoleucine tRNA synthetase enzyme. In this concept we discuss examples that have inspired our research as well as potential directions for future advancement of this field. [source]


    Methylazacalixpyridines: Remarkable Bridging Nitrogen-Tuned Conformations and Cavities with Unique Recognition Properties

    CHEMISTRY - A EUROPEAN JOURNAL, Issue 36 2006
    Han-Yuan Gong
    Abstract Methylazacalix[n]pyridines (n = 4, 8) and methylazacalix[m]arene[n]pyridines (m = n = 2, 4) have been synthesized by a convenient fragment coupling approach starting from 2,6-dibromopyridine, 2,6-diaminopyridine, and benzene-1,3-diamine. Thanks to the intrinsic electronic nature of nitrogen, which can adopt mainly sp2 hybridization, allowing it variously to conjugate, partially conjugate, or not conjugate with the adjacent one or two pyridine rings, the resulting nitrogen-bridged calixpyridine derivatives act as a unique class of macrocyclic host molecules with intriguing conformational structures offering fine-tunable cavities and versatile recognition properties. Whilst in solution it is fluxional, in the solid state methylazacalix[4]pyridine adopts a 1,3-alternate conformation with a C2v symmetry in which every two bridging nitrogen atoms conjugate with one pyridine ring. After protonation, the methylazacalix[4]pyridinium species has a different conjugation system of its four bridging nitrogen atoms, yielding the similar twisted 1,3-alternate conformations with an approximate S4 symmetry. The cavity of each protonated methylazacalix[4]pyridine, however, varies finely to accommodate guest species of different size and geometry, such as planar DMF or HO2CCO2, ion, a twisted HO2CCO2, ion, and a tetrahedral ClO4, ion. As giant macrocyclic hosts, both methylazacalix[8]pyridine and methylazacalix[4]arene[4]pyridine interact efficiently with fullerenes C60 and C70 through van der Waals forces. Their ease of preparation, versatile conformational structures, and recognition properties make these multinitrogen-containing calixarenes or cyclophanes unique and powerful macrocyclic hosts in supramolecular chemistry. [source]


    N -Linked Glycosylated , -Peptides Are Resistant to Degradation by Glycoamidase A

    CHEMISTRY & BIODIVERSITY, Issue 12 2005
    Matthew
    , -Peptides are resistant to degradation by a variety of proteolytic enzymes that rapidly degrade natural , -peptides. This is one of many characteristics that make , -peptides an attractive class of compounds for drug discovery efforts. To further understand the molecular recognition properties of , -peptides and the ability of enzymes to degrade them, we have synthesized a series of N- linked glycosylated , - and , -peptides, and tested their stability towards a glycosidase. We found that glyco- , -peptides that contain N- acetylglucosamine (1) or N,N -diacetylchitobiose (2) are completely stable to degradation by glycoamidase A. In comparison, the glyco- , -peptides 3 and 4 containing N -acetylglucosamine or N,N -diacetylchitobiose are degraded. Inhibition experiments using increasing concentrations of a glyco- , -peptide fail to inhibit degradation of the corresponding glyco- , -peptide, even when the glyco- , -peptide is at a 128-fold higher concentration than the glyco- , -peptide. Evidently, the glyco- , -peptides have a much weaker affinity for the active site of the glycosidase than the corresponding glyco- , -peptide. These and the results with proteolytic enzymes suggest that the additional CH2 group introduced into the , -amino acid residues causes , -peptides not to be recognized by hydrolytic enzymes. The results described herein suggest the potential of , -peptides that are functionalized with carbohydrates for biological and biomedical investigations, without having to be concerned about the carbohydrate being removed. [source]


    Study on the Anion Recognition Properties of Synthesized Receptors (III): Convenient Synthesis and Anion Recognition Property of Bisthiosemicarbazone Derivative

    CHINESE JOURNAL OF CHEMISTRY, Issue 10 2006
    You-Ming Zhang
    Abstract A new series of bisthiosemicarbazone derivative receptors (1, 2 and 3) have been synthesized by simple steps in good yields. Their anion recognition properties were studied by UV-Vis and 1H NMR spectroscopy. The result showed that the receptors 1, 2 and 3 all had a better selectivity to F,, CH3COO, and H2PO4,, but no evident binding with Cl,, Br,, I,, NO3, and HSO4,. Upon addition of the three anions to the receptors in DMSO, the solution acquired a color change from colorless to dark yellow that can be observed by the naked-eyes, thus the receptors can act as fluoride ion sensors even in the presence of other halide ions. The data showed that it was regular that the three receptors had different binding ability with the three anions. For the same anion, the association constants followed the trend: receptor 1>3>2. The UV-Vis data indicates that a 1:1 stoichiometry complex is formed through hydrogen bonding interactions between compound 1, 2 or 3 and anions. [source]


    Synthesis and characterization of novel chiral ionic liquids and investigation of their enantiomeric recognition properties

    CHIRALITY, Issue 2 2008
    David K. Bwambok
    Abstract We report the synthesis and characterization of amino acid ester based chiral ionic liquids, derived from L - and D -alanine tert butyl ester chloride. The synthesis was accomplished via an anion metathesis reaction between commercially available L - and D -alanine tert butyl ester chloride using a variety of counterions such as lithium bis (trifluoromethane) sulfonimide, silver nitrate, silver lactate, and silver tetrafluoroborate. Both enantiomeric forms were obtained as confirmed by bands of opposite sign in the circular dichroism spectra. The L - and D -alanine tert butyl ester bis (trifluoromethane) sulfonimide were obtained as liquids at room temperature and intriguingly exhibited the highest thermal stability (up to 263°C). In addition, the ionic liquids demonstrated enantiomeric recognition ability as evidenced by splitting of racemic Mosher's sodium salt signal using a liquid state 19F nuclear magnetic resonance (NMR) and fluorescence spectroscopy. The L - and D -alanine tert butyl ester chloride resulted in solid salts with nitrate, lactate, and tetrafluoroborate anions. This illustrates the previously observed tunability of ionic liquid synthesis, resulting in ionic liquids of varying properties as a function of varying the anion. Chirality, 2008. © 2007 Wiley-Liss, Inc. [source]