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12700252 | Structure-function studies of Escherichia coli RpoH (sigma32) by in vitro linker insertion mutagenesis. | The sigma factor RpoH (sigma(32)) is the key regulator of the heat shock response in Escherichia coli. Many structural and functional properties of the sigma factor are poorly understood. To gain further insight into RpoH regions that are either important or dispensable for its cellular activity, we generated a collect... |
12698291 | Evolution of chromatin-remodeling complexes: comparative genomics reveals the ancient origin of "novel" compensasome genes. | Dosage compensation in Drosophila is mediated by a complex, called compensasome, composed of at least five proteins and two noncoding RNAs. Genes encoding compensasome proteins have been collectively named male-specific lethals or msls. Recent work showed that three of the Drosophila msls (msl-3, mof, and mle) have an ... |
12695530 | Identification of essential residues involved in the allosteric modulation of the human A(3) adenosine receptor. | We examined the effects on allosteric modulation and ligand binding of the mutation of amino acid residues of the human A(3) adenosine receptor (A(3)AR) that are hypothesized to be near one of three loci: the putative sodium binding site, the putative ligand binding site, and the DRY motif in transmembrane helical doma... |
12692247 | Human papillomavirus type 16 E7 peptide-directed CD8+ T cells from patients with cervical cancer are cross-reactive with the coronavirus NS2 protein. | Human papillomavirus type 16 (HPV16) E6 and E7 oncoproteins are required for cellular transformation and represent candidate targets for HPV-specific and major histocompatibility complex class I-restricted CD8(+)-T-cell responses in patients with cervical cancer. Recent evidence suggests that cross-reactivity represent... |
12692243 | Recruitment of Tat to heterochromatin protein HP1 via interaction with CTIP2 inhibits human immunodeficiency virus type 1 replication in microglial cells. | The Tat protein of human immunodeficiency virus type 1 (HIV-1) plays a key role as inducer of viral gene expression. We report that Tat function can be potently inhibited in human microglial cells by the recently described nuclear receptor cofactor chicken ovalbumin upstream promoter transcription factor-interacting pr... |
12692238 | Human rhinovirus type 2 is internalized by clathrin-mediated endocytosis. | Using several approaches, we investigated the importance of clathrin-mediated endocytosis in the uptake of human rhinovirus serotype 2 (HRV2). By means of confocal immunofluorescence microscopy, we show that K(+) depletion strongly reduces HRV2 internalization. Viral uptake was also substantially reduced by extraction ... |
12692220 | Characterization of the minimal DNA binding domain of the human papillomavirus e1 helicase: fluorescence anisotropy studies and characterization of a dimerization-defective mutant protein. | The E1 helicase of papillomaviruses is required for replication of the viral double-stranded DNA genome, in conjunction with cellular factors. DNA replication is initiated at the viral origin by the assembly of E1 monomers into oligomeric complexes that have unwinding activity. In vivo, this process is catalyzed by the... |
12692219 | Activity of the human papillomavirus type 16 late negative regulatory element is partly due to four weak consensus 5' splice sites that bind a U1 snRNP-like complex. | The human papillomavirus (HPV) life cycle is tightly linked to differentiation of the squamous epithelia that it infects. Capsid proteins, and hence mature virions, are produced in the outermost layer of differentiated cells. As late gene transcripts are produced in the lower layers, posttranscriptional mechanisms like... |
12691704 | Association between human papillomavirus 16 E6 variants and human leukocyte antigen class I polymorphism in cervical cancer of Swedish women. | Persistent infection with human papillomavirus (HPV), particularly HPV16, represents the prime risk factor in cervical carcinogenesis. HPV variants (e.g., within the E6 gene) together with immunogenetic factors of the host may be responsible either for effective viral clearance, or alternatively, for viral persistence.... |
12692886 | Induced circular dichroism by chiral molecular interaction. | Molecular interactions between chiral (nonracemic) and achiral compounds can give rise to induced circular dichroism (ICD) of the achiral counterpart, provided the latter absorbs in the UV or visible region under study. The CD spectra thus obtained are of interest as indicators of the absolute configuration of the chir... |
12672015 | Localization of KCNC1 (Kv3.1) potassium channel subunits in the avian auditory nucleus magnocellularis and nucleus laminaris during development. | The KCNC1 (previously Kv3.1) potassium channel, a delayed rectifier with a high threshold of activation, is highly expressed in the time coding nuclei of the adult chicken and barn owl auditory brainstem. The proposed role of KCNC1 currents in auditory neurons is to reduce the width of the action potential and enable n... |
12670654 | Design and synthesis of broad-based mono- and bi- cyclic inhibitors of FIV and HIV proteases. | Based on the substrate transition state and our strategy to tackle the problem of drug resistance, a series of HIV/FIV protease (HIV /FIV PR) monocyclic inhibitors incorporating a 15- or 17-membered macrocycle with an equivalent P3 or P3' group and a unique unnatural amino acid, (2R, 3S)-3-amino-2-hydroxy-4-phenylbutyr... |
12668076 | Optimization of cellular nucleotide extraction and sample preparation for nucleotide pool analyses using capillary electrophoresis. | Cell extraction and further sample preparation for nucleotide pool analysis using capillary electrophoresis was faster and simpler using volatile extraction solvents (e.g. organic solvents and de-ionized water) compared to the commonly applied acids dissolved in water (e.g. perchloric acid and trichloracetic acid). Tem... |
12654496 | Phage display for detection of biological threat agents. | The essential element of any immuno-based detector device is the probe that binds analyte and, as a part of the analytical platform, generates a measurable signal. The present review summarizes the state of the art in development of the probes for detection of the biological threat agents: toxins, bacteria, spores and ... |
14578110 | Synthesis, characterization and in vitro evaluation of dimethyl-beta-cyclodextrin-4-biphenylylacetic acid conjugate. | Biphenylylacetic acid (BPAA) was linked to the free hydroxyl group of 2,6-di-O-methyl-beta-Cyclodextrin (DM-beta-CyD) through an ester linkage to obtain the site specific release of the drug to the colon. The conjugate at 1:1 mole ratio was separated from the reaction mixture by semipreparative reverse-phase HPLC and c... |
14571325 | Zinc protoporphyrin IX binds heme crystals to inhibit the process of crystallization in Plasmodium falciparum. | The intraerythrocytic Plasmodium falciparum parasite converts most of host hemoglobin heme into a nontoxic heme crystal. Erythrocyte zinc protoporphyrin IX, normally present at 0.5 microM, which is a ratio of 1:40,000 hemes, can elevate 10-fold in some of the anemias associated with malaria disease protection. This wor... |
14565448 | Molecular recognition of quadruplex DNA by quinacridine derivatives. | The interaction of monomeric and dimeric quinacridines with quadruplex DNA has been investigated using a variety of biophysical methods. Both series of compounds were shown to exhibit a high affinity for the G4 conformation with two equivalent binding sites. As shown from the SPR and dialysis experiments the macrocycli... |
14565338 | Synthesis of an asymmetrically substituted AZA crown ether as metal and amino acid binding site in DNA conjugates. | Crown ether 4 as a receptor core for protonated primary amines such as amino acids has been synthesized and incorporated into oligodeoxynucleotides as dangling ends. |
12935435 | Therapeutic and hemolytic evaluation of in-situ liposomal preparation containing amphotericin - beta complexed with different chemically modified beta - cyclodextrins. | <h4>Purpose</h4>The objective of this study was to evaluate therapeutic and haemolytic effects of liposomal preparation derived from proliposome entrapping inclusion complex of amphotericin B (AmB) with the chemically modified beta-cyclodextrin (beta-CD).<h4>Methods</h4>a series of liposomal AmB formulations with varyi... |
12926374 | Synthesis and characterization of mannosyl mimetic derivatives based on a beta-cyclodextrin core. | The synthesis of branched beta-cyclodextrins substituted with mannosyl mimetic derivatives at one primary hydroxy group is described. It was shown that the self-inclusion phenomenon observed for the target compounds in water did not preclude the inclusion properties of the cyclodextrin moiety. |
12926373 | Thiourea-linked upper rim calix[4]arene neoglycoconjugates: synthesis, conformations and binding properties. | The thiourea group has been exploited to link two or four carbohydrate units at the upper rim of tetrapropoxycalix[4]arene derivatives in the cone conformation. Two synthetic methodologies were used, the first one consisting of the condensation of di- and tetraminocalix[4]arenes with the isothiocyanate of monosaccharid... |
12926370 | The four-electron diamagnetic ring current of porphycene. | Porphycene, an isomer that can replace porphin in chemical and biochemical contexts, is predicted by ab initio calculation to exhibit a global diatropic pi ring current with bifurcation across the four pyrrole units of the macrocycle. Analysis of the orbital contributions to the current density in porphycene reveals th... |
12926346 | 1,3,5-tristyrylbenzene dendrimers: a novel model system to explore oxygen quenching in a highly organized environment. | Control of the efficiency of photoisomerization by oxygen was demonstrated for 1,3,5-tristyrylbenzene dendrimers 1-3; the large dendrons do not significantly affect the photochemistry itself due to volume-conserving isomerization mechanisms but may affect the mobility of the molecules. |
12926291 | Spectrophotometric study on the thermodynamics of binding of alpha- and beta-cyclodextrin towards some p-nitrobenzene derivatives. | Binding properties of native alpha- and beta-cyclodextrin towards some nitrobenzene derivatives have been studied by means of UV-vis spectrophotometry. The former host is able to form complexes having 1:1 and 1:2 stoichiometric ratios with these guests, while only 1:1 complexes are detected with the latter host. A care... |
12918972 | High ionic strength glucose-sensing photonic crystal. | We demonstrate a colorimetric glucose recognition material consisting of a crystalline colloidal array embedded within a polyacrylamide-poly(ethylene glycol) (PEG) hydrogel, or a polyacrylamide-15-crown-5 hydrogel, with pendent phenylboronic acid groups. We utilize a new molecular recognition motif, in which boronic ac... |
12885047 | Cyclodextrin-assisted capillary electrophoresis for determination of the cyclic nitramine explosives RDX, HMX and CL-20 comparison with high-performance liquid chromatography. | A sulfobutyl ether-beta-cyclodextrin-assisted electrokinetic chromatographic method was developed to rapidly resolve and detect the cyclic nitramine explosives 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaaza-isowurtzitane (CL-20), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and hexahydro-1,3,5-trinitro-1,3,5-t... |
12862386 | Fast enantioseparation of arylglycine amides by capillary electrophoresis with highly sulfated-beta-cyclodextrin as a chiral selector. | Nine racemic arylglycine amides were synthesized and successfully enantioseparated by capillary electrophoresis (CE) using highly sulfated beta-cyclodextrin (HS-beta-CD) as a chiral selector. Baseline enantioseparation of the analytes was obtained around neutral pH but not in the acidic conditions that are commonly use... |
12834286 | Purification, characterization, and sequence analysis of two alpha-amylase isoforms from azuki bean, Vigna angularis, showing different affinity towards beta-cyclodextrin sepharose. | Two alpha-amylase isoforms designated VAAmy1 and VAAmy2 were purified from cotyledons of germinating seedlings of azuki bean (Vigna angularis). VAAmy1 apparently had lower affinity towards a beta-cyclodextrin Sepharose column than VAAmy2. Molecular weights of VAAmy1 and VAAmy2 were estimated to be 47,000 and 44,000, re... |
12833571 | Studies of the interactions between the anticytokeratin 8 monoclonal antibody TS1, its antigen and its anti-idiotypic antibody alphaTS1. | The monoclonal antibody TS1 against cytokeratin 8 and its antiidiotype alphaTS1 have been used for immunotargeting and therapy of carcinomas in experimental tumor model systems. The interaction surfaces between mab TS1, the cytokeratin 8 epitope, and its anti-idiotypic antibody, alphaTS1, were studied in detail in orde... |
12833570 | Synthesis, characterization and immunochemical evaluation of cephalosporin antigenic determinants. | Lack of knowledge of the exact chemical structure of cephalosporin antigenic determinants has hindered clinical interpretation of adverse reactions to these drugs and delayed understanding of the mechanisms involved in the specific recognition and binding of IgE molecules to these antigenic determinants. We further res... |
12833569 | Measurement of dissociation constants of inhibitors binding to Src SH2 domain protein by non-covalent electrospray ionization mass spectrometry. | A mass spectrometric protocol for identifying ligands with a wide range of affinities (3-101 microM) and quantitative spectral analysis for non-covalent interactions have been developed using Src SH2 as a target. Dissociation constants of five compounds, three with a phospho moiety, one with a sulphonic acid group and ... |
12833568 | Reexamination of the recognition preference of the specificity pocket of the Abl SH3 domain. | Src homology-3 (SH3) domains mediate important protein-protein interactions in a variety of normal and pathological cellular processes, thus providing an attractive target for the selective interference of SH3-dependent signaling events that govern these processes. Most SH3 domains recognize proline-rich peptides with ... |
12833567 | Anti-beta2-glycoprotein I antibodies recognizing platelet factor 4-heparin complex in antiphospholipid syndrome in patient substantiated with mouse model. | The antiphospholipid syndrome is defined by the presence of antiphospholipid antibodies associated with arterial and/or venous thrombosis, and recurrent abortion accompanied often by thrombocytopenia. These antibodies are heterogeneous and react against phospholipid-binding proteins such as beta2-glycoprotein I (beta2G... |
12833566 | Conformational restrictions in the active site of unliganded human caspase-3. | Caspases are cysteine proteases that play a critical role in the initiation and regulation of apoptosis. These enzymes act in a cascade to promote cell death through proteolytic cleavage of intracellular proteins. Since activation of apoptosis is implicated in human diseases such as cancer and neurodegenerative disorde... |
12833565 | An improved model of association for VH-VL immunoglobulin domains: asymmetries between VH and VL in the packing of some interface residues. | The antibody-binding site is formed as a result of the association between VH and VL domains. Several studies have shown that this association plays an important role in the mechanism of antigen-antibody interaction (Stanfield et al. Structure 1: 83-93, 1993). Considering this, we propose that variations in the VH-VL a... |
12830925 | Enantiomeric separation of tocainide and its analogues on an optically active crown ether-based stationary phase by liquid chromatography. | Tocainide and its 14 analogues were resolved on a chiral stationary phase (CSP) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 covalently bonded to silica gel. The resolution was quite good, the separation (alpha) and resolution factors (Rs) being 1.84-15.32 and 1.34-13.78, respectively. Especially, the result for... |
12830922 | Analysis of naphthalenesulfonate compounds by cyclodextrin-mediated capillary electrophoresis with sample stacking. | This study systematically investigates the optimal conditions for analyzing the positional isomers of multi-charged naphthalenesulfonate compounds by cyclodextrin-mediated capillary electrophoresis (CE). Specifically, this work employs large-volume sample injection with the electrode polarity switching technique. The m... |
12830895 | High-speed simultaneous ion-exclusion/cation-exchange chromatography of anions and cations on a weakly acidic cation-exchange resin column. | The simultaneous ion-exclusion/cation-exchange separation column packed with a polymethacrylate-based weakly acidic cation-exchange resin of 3 microm particle size was used to achieve the simultaneous high-speed separation of anions and cations (Cl(-), NO3(-), SO4(2-), Na(+), K(+), NH4(+), Ca(2+) and Mg(2+)) commonly f... |
12830894 | Mixed-mode electrokinetic chromatography of aromatic bases with two pseudo-stationary phases and pH control. | The electrokinetic chromatographic (EKC) separation of a series of aromatic bases was achieved utilising an electrolyte system comprising an anionic soluble polymer (polyvinylsulfonic acid, PVS) and a neutral beta-cyclodextrin (beta-CD) as pseudo-stationary phases. The separation mechanism was based on a combination of... |
12830884 | Ion-exclusion chromatography with conductimetric detection of aliphatic carboxylic acids on a weakly acidic cation-exchange resin by elution with benzoic acid-beta-cyclodextrin. | In this study, an aqueous solution consisting of benzoic acid with low background conductivity and beta-cyclodextrin (beta-CD) of hydrophilic nature and the inclusion effect to benzoic acid were used as eluent for the ion-exclusion chromatographic separation of aliphatic carboxylic acids with different pKa values and h... |
12827277 | RNA-mediated gene silencing. | A number of gene-silencing phenomena including co-suppression discovered in plants, quelling in fungi and RNA interference in animals have been revealed to have steps in common. All occur in the cytoplasm at a post-transcriptional level with the mRNAs of target genes degraded in a sequence-specific manner. Small non-co... |
12823846 | In vivo imaging approaches in animal models of rheumatoid arthritis. | The interaction of activated leukocytes with the rheumatoid synovial environment is a key process in arthritis. Understanding this process will play an important role in designing effective treatments. In vivo imaging approaches combined with molecular genetics in animal models provide important tools to address these ... |
12815861 | [Effect of infrared laser radiation on sorption of dry cartilage and connective tissue preparations]. | Cartilaginous and connective tissues were exposed to a moderate-intensity IR laser treatment with IR radiometric temperature control. The isotherms of water sorption by dry preparations of intact and laser-treated tissues were obtained and calculated in terms of well known models. It was shown that the sorption capacit... |
12809290 | Characterization of lead removal from contaminated soils by nontoxic soil-washing agents. | Few effective strategies exist for remediating and restoring metal-contaminated soils. We have evaluated the potential of two environmentally compatible, nondestructive, biological soil-washing agents for remediating aged, lead-contaminated soils. Two contaminated soils were washed with 10 mM rhamnolipid biosurfactant ... |
12803918 | Formation of functional cell membrane domains: the interplay of lipid- and protein-mediated interactions. | Numerous cell membrane associated processes, including signal transduction, membrane sorting, protein processing and virus trafficking take place in membrane subdomains. Protein-protein interactions provide the frameworks necessary to generate biologically functional membrane domains. For example, coat proteins define ... |
12803084 | Non-covalent dendrimer-porphyrin interactions: the intermediacy of H-aggregates? | The interaction of anionic meso-tetrakis(4-sulfonatophenyl)porphyrin (TSPP) with poly(amidoamine) (PAMAM) dendrimers of generations 2 and 4 in aqueous solution was investigated with steady-state absorption and fluorescence techniques. At low dendrimer concentrations, the formation of low absorptive/emissive species occ... |
12803072 | Direct proof of electron transfer in a rigid first generation triphenyl amine core dendrimer substituted with a peryleneimide acceptor. | The combination of nanosecond transient absorption experiments and single photon timing experiments proved the occurrence of an electron transfer process in the triphenyl amine core dendrimer, N1P1, by demonstrating the presence of an ion-pair absorption for N1P1 in solvents of medium polarity. By means of femtosecond ... |
12803071 | Ultrafast charge separation and radiationless relaxation processes from higher excited electronic states of directly linked porphyrin-acceptor dyads. | We have investigated photoinduced electron transfer (ET) and related processes from the higher excited electronic state (S2) of Zn-porphyrin-imide acceptor directly linked supramolecular systems (ZP-I) designed especially for the critical studies of the energy gap law (EGL) of the charge separation (CS) from the S2 sta... |
12794869 | Influence of response factors on determining equilibrium association constants of non-covalent complexes by electrospray ionization mass spectrometry. | A method for determining the equilibrium association constant of a complexation reaction A + B left harpoon over right harpoon AB by electrospray ionization mass spectrometry is described. The method consists in measuring the relative intensities of the peaks corresponding to A and to AB in equimolar A-B solutions at d... |
12794937 | Therapy and prophylaxis of inhaled biological toxins. | This review highlights the current lack of therapeutic and prophylactic treatments for use against inhaled biological toxins, especially those considered as potential biological warfare (BW) or terrorist threats. Although vaccine development remains a priority, the use of rapidly deployable adjunctive therapeutic or pr... |
12792937 | Two-dimensional supramolecular self-assembly probed by scanning tunneling microscopy. | Supramolecular chemistry has a very large impact on chemistry of current interest and the use of non-covalent but directional forces is appealing for the construction of 'supramolecular architectures'. The invention of scanning probe microscopy techniques has opened new doorways to study these concepts on surfaces. Thi... |
12785790 | Nanoparticle-cored dendrimers: synthesis and characterization. | The synthesis and characterization of a group of new dendrimers-namely, nanoparticle-cored dendrimers (NCDs)-are described. These materials were obtained by the reduction of hydrogen tetrachloroaurate phase-transferred into toluene in the presence of Fréchet-type polyaryl ether dendritic disulfide wedges of generation ... |
12785785 | A novel family of ordered, mesoporous inorganic/organic hybrid polymers containing covalently and multiply bound microporous organic hosts. | We have prepared a new family of periodic hybrid polymers containing microporous cavities provided by covalently bound organic hosts. Cyclodextrin (CD) or calixarene (CX) hosts are attached to four or more trialkoxysilyl groups, which are polymerized to form a polysilsesquioxane matrix. Structural integrity is provided... |
12785784 | Supramolecular assembly of poly(phenylene vinylene) with crown ether substituents to form nanoribbons. | Poly(para-phenylene vinylene) with crown ether substituents (C-PPV) could form nanoribbons through supramolecular assembly with K(+) in dilute chloroform solution. The length of the nanoribbons increased with an increase in the standing time of the C-PPV/K(+) solution. Experimental evidence to support the interaction b... |
12785781 | Effect of 3-hydroxyproline residues on collagen stability. | Collagen is an integral part of many types of connective tissue in animals, especially skin, bones, cartilage, and basement membranes. A fibrous protein, collagen has a triple-helical structure, which is comprised of strands with a repeating Xaa-Yaa-Gly sequence. l-Proline (Pro) and 4(R)-hydroxy-l-proline (4-Hyp) resid... |
12785778 | Exploiting amyloid fibril lamination for nanotube self-assembly. | Fundamental questions about the relative arrangement of the beta-sheet arrays within amyloid fibrils remain central to both its structure and the mechanism of self-assembly. Recent computational analyses suggested that sheet-to-sheet lamination was limited by the length of the strand. On the basis of this hypothesis, a... |
12785758 | pH- and thermosensitive supramolecular assembling system: rapidly responsive properties of beta-cyclodextrin-conjugated poly(epsilon-lysine). | beta-Cyclodextrin-conjugated poly(epsilon-lysine) (beta-CDPL) was synthesized as a novel polymeric host for constructing a smart supramolecular assembling system. Systematic studies on the inclusion complexation between the polymeric host with an alpha- or beta-CD cavity and a model guest molecule provided evidence tha... |
12785857 | Dendrimer-tuned formation of luminescent organic microcrystals. | Microcrystals of an organic fluorescent dye, 4-n-octylamino-7-nitrobenz-2-oxa-1,3-diazole (NBD-C8), were prepared by reprecipitation in water. The crystallization kinetics was monitored by UV/vis absorption spectroscopy, and a model was proposed. The size and shape of the microcrystals were analyzed by laser light scat... |
12785855 | Synthesis, structures, and conformational characteristics of calixarene monoanions and dianions. | The synthesis, complete characterization, and solid state structural and solution conformation determination of calix[n]arenes (n = 4, 6, 8) is reported. A complete series of X-ray structures of the alkali metal salts of calix[4]arene (HC4) illustrate the great influence of the alkali metal ion on the solid state struc... |
12785852 | Molecular recognition of alpha,beta-unsaturated carbonyl compounds using aluminum tris(2,6-diphenylphenoxide) (ATPH): structural and conformational analysis of ATPH complexes and application to the selective vinylogous aldol reaction. | Various alpha,beta-unsaturated carbonyl compounds were coordinated with aluminum tris(2,6-diphenylphenoxide) (ATPH) to give the corresponding Lewis acid-base complexes in a distinctive coordination fashion (selective coordination). ATPH recognizes carbonyl substrates and subsequently orients itself as it forms a stable... |
12785848 | Rational design of a calcium-binding protein. | Calcium ions play key roles as structural components in biomineralization and as a second messenger in signaling pathways. We have introduced a de novo designed calcium-binding site into the framework of a non-calcium-binding protein, domain 1 of CD2. The resulting protein selectively binds calcium over magnesium with ... |
12785838 | Cross-reactive arrays based on three-way junctions. | We report herein a novel system for the parallel processing of molecular recognition events utilizing arrays of oligonucleotide-based fluorescent sensors to characterize hydrophobic molecules in solution. The binding domains of the sensors were based on three-way junctions that utilize double helical stems as framework... |
12785834 | Supramolecular interactions between fullerenes and porphyrins. | Perdew-Burke-Ernzerhof density functional theory calculations have been carried out to investigate the host-guest interactions for several fullerene-porphyrin supramolecular complexes. The nature of the interactions has been discussed. The fullerene-porphyrin interaction energies for the complexes studied are found to ... |
12785833 | Hemoglobin dendrimers: functional protein clusters. | A cluster of cross-linked hemoglobin tetramers was prepared by conjugating active esters to amino groups of a starburst dendrimer. Comparison of oxygen-binding properties of the protein cluster to those of nonclustered species reveals an increase in affinity and a decrease in cooperativity in the cluster. The altered o... |
12785819 | The total synthesis of (+)-migrastatin. | The first total synthesis of (+)-migrastatin, a macrolide natural product with interesting antimetastatic properties, has been accomplished. Our concise and flexible approach utilizes a Lewis acid-catalyzed diene aldehyde condensation to install the three contiguous stereocenters and the trisubstituted (Z)-alkene of mi... |
12785805 | Interlocked chiral nanotubes assembled from quintuple helices. | Homochiral helical chains were rationally synthesized from C2-symmetric 1,1-binaphthyl-6,6'-bipyridine ligands and linear metal-connecting points, Ni(acac)2. Five such homochiral helices associate in parallel to form nanotubes of 2 x 2 nm in dimensions which further intertwine to form periodically ordered, interlocked ... |
12778698 | Self-assembled dimers with supramolecular chirality. | The possibilities to form dimeric capsules with supramolecular chirality from tetraurea calix[4]arenes composed of two different phenolic urea units are discussed in general and demonstrated experimentally for various selected examples. |
12775055 | Alkaline hydrolysis of the cyclic nitramine explosives RDX, HMX, and CL-20: new insights into degradation pathways obtained by the observation of novel intermediates. | Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX, I) and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) hydrolyze at pH > 10 to form end products including NO2-, HCHO, HCOOH, NH3, and N2O, but little information is available on intermediates, apart from the tentatively identified pentahydro-3,5-dinitro-1,3,5-triaza... |
12772909 | Porphyrin hetero-dimer as charge separating system for photocurrent generation. | Introducing a porphyrin bearing electron acceptor onto a self-assembled monolayer (SAM) using a supramolecular method to form a hetero-dimer increased the photocurrent value compared with using porphyrin without an electron acceptor. |
12772906 | Photoluminescent supramolecular networks from metal-mediated assembly of polythia conjugated dieneyne. | Polythia conjugated dieneyne 1,1,2,5,6,6-hexakis(phenylthio)-1,5-diene-3-yne and its one- and two-dimensional silver(I) coordination polymers, which exhibited fluorescence and redox properties, were prepared and investigated. |
12772900 | Micropatterns constructed from Au nanoparticles. | Covalently linked Au-NPs micropatterns have been successfully fabricated from the self-assembly film composed of 4-mercaptophenol-capped Au nanoparticles (Au-NPs) and -N2+ containing polymers of nitro-diazoresin (NDR) by selective exposure to UV light and development in sodium dodecyl sulfate (SDS) aqueous solution. Th... |
12769850 | MOF-regulated acetylation of MSL-3 in the Drosophila dosage compensation complex. | Dosage compensation ensures equal expression of X-linked genes in males and females. In Drosophila, equalization is achieved by hypertranscription of the male X chromosome. This process requires an RNA/protein containing dosage compensation complex (DCC). Here we use RNA interference of individual DCC components to def... |
12771123 | Caveolae/raft-dependent endocytosis. | Although caveolae are well-characterized subdomains of glycolipid rafts, their distinctive morphology and association with caveolins has led to their internalization being considered different from that of rafts. In this review, we propose that caveolae and rafts are internalized via a common pathway, caveolae/raft-dep... |
12771122 | Is HP1 an RNA detector that functions both in repression and activation? | Heterochromatin is defined as regions of compact chromatin that persist throughout the cell cycle (Heitz, 1928). The earliest cytological observations of heterochromatin were followed by ribonucleotide labeling experiments that showed it to be transcriptionally inert relative to the more typical euchromatic regions tha... |
12772308 | Self-assembled monolayers of novel surface-bound dendrons: peripheral structure determines surface organization. | The synthetic and functional versatility of dendrimers and their well-defined shapes make them attractive molecules for surface modification. We synthesized six structurally very similar surface-bound dendrons and used them as building blocks for the preparation of self-assembled monolayers (SAMs) on a gold surface. We... |
12772303 | meso-substituted aromatic 34pi core-modified octaphyrins: syntheses, characterization and anion binding properties. | Modified octaphyrins with 34pi electrons have been synthesized and characterized following a simple synthetic methodology. An acid-catalyzed alpha,alpha coupling of tetrapyrranes containing furan, thiophene and selenophene rings resulted in the formation of the respective octaphyrins in relatively good yield. Solution ... |
12772293 | The structure of the sugar residue in glycated human serum albumin and its molecular recognition by phenylboronate. | Quantification of the extent of glycation of human serum albumin (HSA) and of haemoglobin provides a record of average mid- and long-term blood-sugar concentrations, respectively; this is very useful for the management of diabetes. The reaction of D-glucose with propylamine affords the corresponding Schiff base, N-prop... |
12769382 | Comparative study of the response of membrane electrodes based on calix[6]arene and calix[8]arene derivatives to organic ammonium ions. | p-tert-Butylcalix[8]arene-octaacetic acid octaethyl ester and calix[8]arene-octaacetic acid octaethyl ester well recognized 2-phenylethylamine and phenylalanine methyl ester compared with the corresponding calix[6]arene derivatives. Moreover, the calix[8]arene derivatives, especially one having tert-butyl groups, gave ... |
12769380 | Electrochemical and phosphorescent properties of new mixed-ligand Ir(II) complexes coordinated with both terpyridine and various bipyridine derivatives. | Seven useful mixed-ligand complexes in the form of [Ir(terpy)(L)Cl]2+ were prepared and their spectroscopic and electrochemical properties were investigated. The ligands used were terpy = 2,2':6',2''-terpyridine, L = 2,2'-bipyridine, 4,4'-dimethyl-2,2'-bipyridine, 4,4'-diphenyl-2,2'-bipyridine, 1,10-phenanthroline, 5-p... |
12769371 | Preparation of uniformly sized molecularly imprinted polymers for phenolic compounds and their application to the assay of bisphenol A in river water. | Uniformly sized molecularly imprinted polymers, which can recognize bisphenol A (BPA), have been prepared by a multi-step swelling and polymerization method using BPA or a structurally related analogue of BPA [p-t-octylphenol (OP) or p-t-butylphenol (BP)] as the template molecule, 4-vinylpyridine as the functional mono... |
12769370 | Evaluation of beta-cyclodextrin bonded silica as a selective sorbent for the solid-phase extraction of 4-nitrophenol and 2,4-dinitrophenol. | A beta-cyclodextrin bonded silica was synthesized by using a convenient method, and was evaluated as a selective sorbent for the solid-phase extraction of 4-nitrophenol and 2,4-dinitrophenol. When double-distilled water was used as the sample matrix, the sorbent showed a strong capacity to adsorb 4-nitrophenol and 2,4-... |
12762683 | "Magic rod" rotaxanes: the hydrogen bond-directed synthesis of molecular shuttles under thermodynamic control. | [reaction: see text] Peptide [2]- and [3]rotaxanes are assembled in high yields under thermodynamic control using hydrogen bonding interactions and reversible cross olefin metathesis. |
12762678 | Synthesis of a [2]catenane around a Ru(diimine)3(2+) scaffold by ring-closing metathesis of olefins. | [reaction: see text] The synthesis of a ruthenium[2]catenane is described. One ring includes two 1,10-phenanthroline moieties, the other a bipyridinic unit. The interlocking ring system was formed by using a double ring closing metathesis reaction. Under irradiation, a rapid and selective decoordination of the bipyridi... |
12762752 | A convergent solution-phase synthesis of the macrocycle Ac-Phe-[Orn-Pro-D-Cha-Trp-Arg], a potent new antiinflammatory drug. | Relatively few cyclic peptides have reached the pharmaceutical marketplace during the past decade, most produced through fermentation rather than made synthetically. Generally, this class of compounds is synthesized for research purposes on milligram scales by solid-phase methods, but if the potential of macrocyclic pe... |
12762714 | Digital processing with a three-state molecular switch. | Certain molecular switches respond to input stimulations producing detectable outputs. The interplay of these signals can be exploited to reproduce basic logic operations at the molecular level. The transition from simple logic gates to complex digital circuits requires the design of chemical systems able to process mu... |
12761798 | Enantioselective strong cation-exchange molecular recognition materials: design of novel chiral stationary phases and their application for enantioseparation of chiral bases by nonaqueous capillary electrochromatography. | New chiral stationary phases derived from enantiomerically pure derivatives of cysteine carrying sulfonic acid groups are synthesized and evaluated for enantiomer separation of chiral bases by non aqueous capillary electrochromatography after bonding to a linker and grafting upon thiol-modified silica particles. Struct... |
12761796 | Separation of (Z)- and (E)-isomers of thioxanthene and dibenz[b,e]oxepin derivatives with calixarenes and resorcinarenes as additives in nonaqueous capillary electrophoresis. | Five acidic calix[4]arenes with carboxylic or sulfonic groups at either the upper or lower rim of the cavity and one resorc[4]arene were investigated to separate three thioxanthenes (flupentixol, clopenthixol, chlorprothixene) and a dibenz[b,e]oxepin derivative (doxepin) with cis-/trans-isomerism by nonaqueous capillar... |
12757394 | Structural effects of carbohydrate-containing polycations on gene delivery. 3. Cyclodextrin type and functionalization. | Linear cationic beta-cyclodextrin (beta-CD)-based polymers can form polyplexes with plasmid DNA and transfect cultured cells. The effectiveness of the gene delivery and the cellular toxicity has been related to structural features in these polycations. Previous beta-CD polycations were prepared from the cocondensation ... |
12758161 | Equilibrium unfolding of RNase Rs from Rhizopus stolonifer: pH dependence of chemical and thermal denaturation. | The conformational stability of RNase Rs was determined with chemical and thermal denaturants over the pH range of 1-10. Equilibrium unfolding with urea showed that values of D(1/2) (5.7 M) and DeltaG(H(2)O) (12.8 kcal/mol) were highest at pH 5.0, its pI and the maximum conformational stability of RNase Rs was observed... |
12758154 | Interactions between PAMAM dendrimers and bovine serum albumin. | Dendrimers are a new class of polymeric materials. They are globular, highly branched, monodisperse macromolecules. Due to their structure, dendrimers promise to be new, effective biomedical materials as oligonucleotide transfection agents and drug carriers. More information about biological properties of dendrimers is... |
12755625 | Specific antibody-DNA interaction: a novel strategy for tight DNA recognition. | Anti-double-stranded DNA monoclonal antibodies against a viral transcriptional regulatory site are capable of discriminating single-base replacements with affinities of 1 x 10(-)(9) M, which were optimized for the length of the duplex used as the immunogen. Their affinity for DNA duplexes of increasing length is lower,... |
12753187 | Development and maturation of Escherichia coli K-12 biofilms. | The development and maturation of E. coli biofilms in flow-chambers was investigated. We found that the presence of transfer constitutive IncF plasmids induced biofilm development forming structures resembling those reported for Pseudomonas aeruginosa. The development occurred in a step-wise process: (i). attachment of... |
12754001 | Scanning electron microscopy and atomic force microscopy imaging of solid lipid nanoparticles derived from amphiphilic cyclodextrins. | Scanning electron microscopy (SEM) and atomic force microscopy (AFM) have been applied to the imagery of solid lipid nanoparticles (SLNs) formulated from an amphiphilic cyclodextrin, 2,3-di-o-alkanoyl-beta-cyclodextrin, beta-CD21C6. Comparison of the results shows that the vacuum drying technique used in sample prepara... |
12752453 | Covalent and three-dimensional structure of the cyclodextrinase from Flavobacterium sp. no. 92. | Starting with oligopeptide sequences and using PCR, the gene of the cyclodextrinase from Flavobacterium sp. no. 92 was derived from the genomic DNA. The gene was sequenced and expressed in Escherichia coli; the gene product was purified and crystallized. An X-ray diffraction analysis using seleno-methionines with multi... |
12754103 | N6-Substituted adenosine derivatives: selectivity, efficacy, and species differences at A3 adenosine receptors. | The activation of the human A(3) adenosine receptor (AR) by a wide range of N(6)-substituted adenosine derivatives was studied in intact CHO cells stably expressing this receptor. Selectivity of binding at rat and human ARs was also determined. Among N(6)-alkyl substitutions, small N(6)-alkyl groups were associated wit... |
12752215 | The effect of cyclodextrins on the in vitro and in vivo properties of insulin-loaded poly (D,L-lactic-co-glycolic acid) microspheres. | In this work we describe the development and characterization of a new formulation of insulin (INS). Insulin was complexed with cyclodextrins (CD) in order to improve its solubility and stability being available as a dry powder, after encapsulation into poly (D,L-lactic-co-glycolic acid) (PLGA) microspheres. The comple... |
12752214 | In vitro effects of a chlorhexidine controlled delivery system. | The aim of this work was study the effect of the chlorhexidine : hydroxypropyl-beta-cyclodextrin (CLX : HP-beta-CD) inclusion compound (IC) on in vitro slabs of bovine dentine. The substantivity, antimicrobial activity, and morphological effect of this inclusion compound were evaluated. Cyclodextrin improves the physic... |
12724530 | Unbiased quantitative proteomics of lipid rafts reveals high specificity for signaling factors. | Membrane lipids were once thought to be homogenously distributed in the 2D surface of a membrane, but the lipid raft theory suggests that cholesterol and sphingolipids partition away from other membrane lipids. Lipid raft theory further implicates these cholesterol-rich domains in many processes such as signaling and v... |
12721375 | Resistance of cell membranes to different detergents. | Partial resistance of cell membranes to solubilization with mild detergents and the analysis of isolated detergent-resistant membranes (DRMs) have been used operationally to define membrane domains. Given the multitude of detergents used for this purpose, we sought to investigate whether extraction with different deter... |
12721287 | Distinct endosomal compartments in early trafficking of low density lipoprotein-derived cholesterol. | We previously studied the early trafficking of low density lipoprotein (LDL)-derived cholesterol in mutant Chinese hamster ovary cells defective in Niemann-Pick type C1 (NPC1) using cyclodextrin (CD) to monitor the arrival of cholesterol from the cell interior to the plasma membrane (PM) (Cruz, J. C., Sugii, S., Yu, C.... |
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