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15198518 | Lipid-based supramolecular systems for topical application: a preformulatory study. | This article describes the production and characterization of monoglyceride-based supramolecular systems by a simple processing technique, avoiding time-consuming procedures, high energy input, and the use of organic solvents. A preformulatory study was performed to study the influence of the experimental parameters on... |
14623769 | Effects of A-317491, a novel and selective P2X3/P2X2/3 receptor antagonist, on neuropathic, inflammatory and chemogenic nociception following intrathecal and intraplantar administration. | We have recently reported that systemic delivery of A-317491, the first non-nucleotide antagonist that has high affinity and selectivity for blocking P2X3 homomeric and P2X2/3 heteromeric channels, is antinociceptive in rat models of chronic inflammatory and neuropathic pain. In an effort to further evaluate the role o... |
14623971 | Cellulosome assembly revealed by the crystal structure of the cohesin-dockerin complex. | The utilization of organized supramolecular assemblies to exploit the synergistic interactions afforded by close proximity, both for enzymatic synthesis and for the degradation of recalcitrant substrates, is an emerging theme in cellular biology. Anaerobic bacteria harness a multiprotein complex, termed the "cellulosom... |
14617779 | Differential hydrophobicity drives self-assembly in Huntington's disease. | Identifying the driving forces and the mechanism of association of huntingtin-exon1, a close marker for the progress of Huntington's disease, is an important prerequisite to finding potential drug targets and, ultimately, a cure. We introduce here a modeling framework based on a key analogy of the physicochemical prope... |
14617770 | Regulation of zinc homeostasis by inducible NO synthase-derived NO: nuclear metallothionein translocation and intranuclear Zn2+ release. | Zn2+ is critical for the functional and structural integrity of cells and contributes to a number of important processes including gene expression. It has been shown that NO exogenously applied via NO donors resulting in nitrosative stress leads to cytoplasmic Zn2+ release from the zinc storing protein metallothionein ... |
14618158 | Raft disorganization leads to reduced plasmin activity in Alzheimer's disease brains. | The serine protease plasmin can efficiently degrade amyloid peptide in vitro, and is found at low levels in the hippocampus of patients with Alzheimer's disease (AD). The cause of such paucity remains unknown. We show here that the levels of total brain plasminogen and plasminogen-binding molecules are normal in these ... |
14615485 | Amyloid fibril formation by lens crystallin proteins and its implications for cataract formation. | The alpha-, beta-, and gamma-crystallins are the major structural proteins within the eye lens and are responsible for its exceptional stability and transparency. Under mildly denaturing conditions, all three types of bovine crystallin assemble into fibrillar structures in vitro. Characterization by transmission electr... |
14615286 | Signaling mechanisms that mediate nitric oxide production induced by acetylcholine exposure and withdrawal in cat atrial myocytes. | Fluorescence microscopy and the NO-sensitive indicator 4,5-diaminofluorescein were used to determine the effects of acetylcholine (ACh) on intracellular NO (NOi) in cat atrial myocytes. Field stimulation (1 Hz) of cells or exposure of quiescent cells to ACh (1 to 10 micromol/L) had no effect on NOi. However, in field-s... |
14613940 | Properties of recombinant human cytosolic sialidase HsNEU2. The enzyme hydrolyzes monomerically dispersed GM1 ganglioside molecules. | Recombinant human cytosolic sialidase (HsNEU2), expressed in Escherichia coli, was purified to homogeneity, and its substrate specificity was studied. HsNEU2 hydrolyzed 4-methylumbelliferyl alpha-NeuAc, alpha 2-->3 sialyllactose, glycoproteins (fetuin, alpha-acid glycoprotein, transferrin, and bovine submaxillary gland... |
14613963 | Heat-induced reformulation of amphotericin B-deoxycholate favours drug uptake by the macrophage-like cell line J774. | <h4>Aim</h4>Heat treatment of deoxycholate-amphotericin B (AmB-DOC) leads to a therapeutically interesting supramolecular rearrangement (h-AmB-DOC); this reformulation improves the therapeutic index of AmB-DOC by reducing amphotericin B (AmB) toxicity in mammalian cell lines from 3- to 10-fold. Its activity in experime... |
14737337 | Strong fluorescence emission induced by supramolecular assembly and gelation: luminescent organogel from nonemissive oxadiazole-based benzene-1,3,5-tricarboxamide gelator. | Supramolecular aggregation of a novel nonfluorescent gelator yields highly luminescent organogels in aprotic organic solvents through intermolecular hydrogen bonding, which is a key motif for both self-assembly and photophysical process control. |
14610620 | Role of IL-13 in regulation of anti-tumor immunity and tumor growth. | Major mediators of anti-tumor immunity are CD4(+) T(h)1 cells and CD8(+) cytotoxic T lymphocytes (CTLs). In tumor-bearing animals, the T(h)1- and CTL-mediated anti-tumor immunity is down-regulated in multiple ways. Better understanding of negative regulatory pathways of tumor immunity is crucial for the development of ... |
14610639 | Characterization of the chlorosome antenna of the filamentous anoxygenic phototrophic bacterium Chloronema sp. strain UdG9001. | The absorption and fluorescence properties of chlorosomes of the filamentous anoxygenic phototrophic bacterium Chloronema sp. strain UdG9001 were analyzed. The chlorosome antenna of Chloronema consists of bacteriochlorophyll (BChl) d and BChl c together with gamma-carotene as the main carotenoid. HPLC analysis combined... |
14612578 | The mature activating natural killer cell immunologic synapse is formed in distinct stages. | Natural killer (NK) cells form a structure at their interface with a susceptible target cell called the activating NK cell immunologic synapse (NKIS). The mature activating NKIS contains a central and peripheral supramolecular activation cluster (SMAC), and includes polarized surface receptors, filamentous actin (F-act... |
14612561 | Membrane cholesterol, lateral mobility, and the phosphatidylinositol 4,5-bisphosphate-dependent organization of cell actin. | Responses to cholesterol depletion are often taken as evidence of a role for lipid rafts in cell function. Here, we show that depletion of cell cholesterol has global effects on cell and plasma membrane architecture and function. The lateral mobility of membrane proteins is reduced when cell cholesterol is chronically ... |
14671366 | Self-recognition in a flexible bis(pyrrole) Schiff base derivative: formation of a one-dimensional hydrogen-bonded polymer. | The title Schiff base compound, N,N'-bis(pyrrol-2-ylmethylene)propane-1,2-diamine, C(13)H(16)N(4), forms an interesting supramolecular structure (a one-dimensional ladder-like polymer) in the solid state that is based on the existence of complementary intermolecular N-H.N=C hydrogen bonds between the monomer units. The... |
14671346 | trans-Diaquabis(1H-imidazole-4,5-dicarboxylate-kappa2N3,O4)manganese(II). | In the title compound, [Mn(C(5)H(3)N(2)O(4))(2)(H(2)O)(2)], the Mn(II) atom lies on an inversion centre, is trans-coordinated by two N,O-bidentate 1H-imidazole-4,5-dicarboxylate monoanionic ligands [Mn-O = 2.202 (3) A and Mn-N = 2.201 (4) A] and two water molecules [Mn-O = 2.197 (4) A], and exhibits a distorted octahed... |
14737355 | Photomodulated molecular recognition of the guanidinium cation. | Azobenzene moieties were incorporated into a synthetic receptor allowing its affinity for the guanidinium cation to be modulated ten-fold by photoirradiation and/or heating. |
14737350 | Highly enantioselective spiro cyclization of 1,6-enynes catalyzed by cationic skewphos rhodium(I) complex. | A cationic rhodium(I) complex having a skewphos ligand is shown to be a highly enantioselective catalyst for asymmetric carbocyclization of 1,6-enynes with tri-substituted olefins to control quaternary stereogenic centers of spiro-rings. |
14737657 | Diamagnetic and paramagnetic ring currents in expanded porphyrins. | Ipsocentric current density maps are computed at the coupled Hartree-Fock level in the 6-31G** basis set for the planar C(2v) B3LYP geometries of the expanded porphyrins, sapphyrin and orangarin. Both give clearly dominant global macrocyclic ring currents, but with opposite senses of circulation: in 22[small pi] sapphy... |
14604991 | Design of chimeric receptor mimics with different TcRVbeta isoforms. Type-specific inhibition of superantigen pathogenesis. | The Staphylococcus aureus enterotoxins (S.E.) A-I, and toxic-shock syndrome toxin TSST-1 act as superantigens to cause overstimulation of the host immune system, leading to the onset of various diseases including food poisoning and toxic shock syndrome. SAgs bind as intact proteins to the DRalpha1 domain of the MHC cla... |
14603035 | Site- and sequence-selective ultrafast hydration of DNA. | Water molecules in the DNA grooves are critical for maintaining structural integrity, conformational changes, and molecular recognition. Here we report studies of site- and sequence-specific hydration dynamics, using 2-aminopurine (Ap) as the intrinsic fluorescence probe and with femtosecond resolution. The dodecamer d... |
14597614 | Secretogranin III binds to cholesterol in the secretory granule membrane as an adapter for chromogranin A. | Granin-family proteins, including chromogranin A (CgA) and secretogranin III (SgIII), are transported to secretory granules (SGs) in neuroendocrine cells. We previously showed that SgIII binds strongly to CgA in an intragranular milieu and targets CgA to SGs in pituitary and pancreatic endocrine cells. In this study, w... |
14597719 | Nanoshell-mediated near-infrared thermal therapy of tumors under magnetic resonance guidance. | Metal nanoshells are a class of nanoparticles with tunable optical resonances. In this article, an application of this technology to thermal ablative therapy for cancer is described. By tuning the nanoshells to strongly absorb light in the near infrared, where optical transmission through tissue is optimal, a distribut... |
19003209 | Immuno-chromatographic assay for diagnosis of feline leukemia virus infection. | Feline leukemia virus (FeLV) infectious disease is one of feline infection diseases spreading broadly all over the world. For bedside diagnosis of FeLV infectious disease, an immuno-chromatographic assay was investigated. Five different monoclonal antibodies were developed against the major core protein FeLV-p27. Among... |
15601532 | Genome-wide characterisation of the binding repertoire of small molecule drugs. | Most, if not all, drugs interact with multiple proteins. One or more of these interactions are responsible for carrying out the primary therapeutic effects of the drug. Others are involved in the transport or metabolic processing of the drug or in the mediation of side effects. Still others may be responsible for activ... |
14690232 | Photoisomerisation and fluorescence behaviour of polyphenylene-based stilbene dendrimers. | The photoinduced structural changes of three polyphenylene-based stilbene dendrimers, G1, G2, and G3, has been studied. They all exhibit fluorescence emission with considerably higher quantum efficiency and longer fluorescence lifetimes compared with the parent stilbene. These dendrimers undergo mutual cis --> trans is... |
14690228 | Supramolecular control of [2 + 2] photodimerization via hydrogen bonding. | The use of supramolecular catalysis to control the photoinduced dimerization of styrene, cinnamate, and stilbene chromophores is reported. The strategy employs the formation of a 2:1 supramolecular assembly in the presence of 5,5-dihexylbarbituric acid (DHB). A 3- to 10-fold increase in dimerization efficiency is obser... |
14690223 | Generation dependent singlet-singlet annihilation within multichromophoric dendrimers studied by polychromatic transient absorption. | Intramolecular kinetic processes in a series of shape-persistent meta- and para-substituted polyphenylene dendrimers bearing different peryleneimide chromophores at the rim have been investigated using time-resolved polychromatic transient absorption measurements. The influence of the generation number and different su... |
14690220 | In situ EPR investigation of the addition of persistent benzyl radicals to acrylates on ZSM-5 zeolites. Direct spectroscopic detection of the initial steps in a supramolecular photopolymerization. | Photolysis of dibenzyl ketone derivatives adsorbed on ZSM-5 zeolites produces persistent benzyl radicals (initiator radicals), which add to methyl acrylates (monomers) to generate persistent adduct radicals. Both initiator and adduct radicals are readily observable by conventional steady-state EPR spectroscopy at room ... |
14651125 | Applying reversible chemistry of CO2 to supramolecular polymers. | Novel supramolecular, reversibly formed polymers featuring self-assembling capsules have been constructed through chemical fixation of CO2 and hydrogen bonding. |
14651123 | Molecular recognition. Self-assembly of molecular trigonal prisms and their host-guest adducts. | Two supramolecular trigonal prisms, each bearing three molecular clefts are shown to form 1:6 and 1:7 host-guest complexes with 9-methylanthracene and one of the prisms forms a 1:2 host-guest complex with a tritopic tri-anthracene guest that registers with the recognition sites of the host. |
14639645 | The convergent synthesis of poly(glycerol-succinic acid) dendritic macromolecules. | The high-yield convergent synthesis of dendrons, dendrimers, and dendritic-linear hybrid macromolecules composed of succinic acid, glycerol, and poly(ethylene glycol) (PEG) is described. This convergent synthesis relies on two orthogonal protecting groups; namely, the benzylidene acetal (bzld) for the protection of the... |
14639640 | Chiral bis(amino alcohol)oxalamide gelators-gelation properties and supramolecular organization: racemate versus pure enantiomer gelation. | Four new chiral bis(amino alcohol)oxalamides (1-4: amino alcohol=leucinol, valinol, phenylglycinol, and phenylalaninol, respectively) have been prepared as low-molecular-weight organic gelators. Their gelation properties towards various organic solvents and mixtures were determined and these were then compared to relat... |
14639639 | Supramolecular control of the template-induced selective photodimerization of 4-methyl-7-O-hexylcoumarin. | A symmetric ditopic molecular receptor (3), containing two identical hydrogen-bonding recognition subunits, was designed and synthesized. These subunits are capable of binding substrates with complementary donor and acceptor sites to form a supramolecular complex through hydrogen bonding. Receptor 3 was designed to acc... |
14639627 | Shape-persistency and molecular function in heteromacrocycles: creation of heteroarenecyclynes and arene-azaarenecyclynes. | On the basis of our concept that the introduction of heteroatoms and shape-persistency into the pi-macrocycles should bring forth striking functions or properties, heteroarenecyclynes (such as oxaarenecyclynes and thiaarenecyclynes) with semi-shape-persistent structure, and arene-azaarenecyclynes with shape-persistent ... |
14602035 | NaIO4-mediated selective oxidative halogenation of alkenes and aromatics using alkali metal halides. | [reaction: see text] NaIO(4) oxidizes alkali metal halides efficiently in aqueous medium to halogenate alkenes and aromatics and produce the corresponding halo derivatives in excellent regio and stereoselectivity. The system also demonstrates the asymmetric version of bromo hydroxylation using beta-cyclodextrin complex... |
14601998 | Extreme complementarity in a macrocycle-tweezer complex. | [reaction: see text] Interaction of a novel pyrene-based tweezer molecule with a macrocyclic ether-imide-sulfone results in formation of a strongly bound complex (K(a) = 24 000 M(-)(1)) in which binding results not only from pi-pi stacking interactions involving pyrene units as donors and macrocyclic naphthalene-tetrac... |
14601973 | Synthesis of 3-aminochroman derivatives by radical cyclization. | [reaction: see text] Enantiomerically pure 5-acetyl-3-amino-3,4-dihydro-2H-1-benzopyran and methyl 3-amino-3,4-dihydro-2H-1-benzopyran-5-carboxylate were successfully synthesized starting from d- or l-serine. The formation of the benzopyran ring involved a radical cyclization step. The enantiomeric purities of the fina... |
14732933 | Immunomodulation by the copolymer glatiramer acetate. | Glatiramer acetate (GA; Copaxone, also known as Copolymer 1 or Cop-1), a copolymer of amino acids, is very effective in the suppression of experimental autoimmune encephalitis (EAE), the animal model for multiple sclerosis (MS), in various species including primates. The immunological cross-reaction between the myelin ... |
14732932 | Molecular imprinting of nitrophenol and hydroxybenzoic acid isomers: effect of molecular structure and acidity on imprinting. | Three nitrophenol isomer-imprinted polymers were prepared under the same conditions using 4-vinylpyridine as a functional monomer. Different recognition capacities for template molecules were observed for the three polymers. Another imprinting system with stronger acidity than nitrophenol isomers, 2-hydroxybenzoic acid... |
14732931 | Structure-based discovery of a new affinity ligand to pancreatic alpha-amylase. | A ligand useful for affinity capture of porcine pancreatic alpha-amylase was found by virtual screening of the commercially available compound data base MDL Available Chemicals Directory. Hits from the virtual screening were investigated for binding by nuclear magnetic resonance (NMR) and surface plasmon resonance. Sel... |
14732930 | A possible molecular mechanism of hanatoxin binding-modified gating in voltage-gated K+-channels. | While S4 is known as the voltage sensor in voltage-gated potassium channels, the carboxyl terminus of S3 (S3C) is of particular interest concerning the site for gating modifier toxins like hanatoxin. The thus derived helical secondary structural arrangement for S3C, as well as its surrounding environment, has since bee... |
14732929 | A survey of the year 2002 literature on applications of isothermal titration calorimetry. | Isothermal titration calorimetry (ITC) is becoming widely accepted as a key instrument in any laboratory in which quantification of biomolecular interactions is a requisite. The method has matured with respect to general acceptance and application development over recent years. The number of publications on ITC has gro... |
14732928 | A survey of the year 2002 commercial optical biosensor literature. | We have compiled 819 articles published in the year 2002 that involved commercial optical biosensor technology. The literature demonstrates that the technology's application continues to increase as biosensors are contributing to diverse scientific fields and are used to examine interactions ranging in size from small ... |
14730111 | Inhibitory effect of some neuroactive steroids on cocaine-induced kindling in mice. | Some neuroactive steroids which positively modulate GABAA receptor activity suppress cocaine-induced kindling but a possible involvement of other neurochemical mechanism in their antiepileptogenic effect remains to be elucidated. To this end, in the present study, we evaluated effects of allopregnanolone, a positive mo... |
14730370 | Improving the aqueous solubility of triclosan by solubilization, complexation, and in situ salt formation. | Triclosan, an antimicrobial, although widely incorporated into many skin care products, toothpastes, and liquid soaps, presents formulation difficulties because it is practically insoluble in water. The objective of this study was to improve the aqueous solubility of triclosan through solubilization, complexation, and ... |
14700229 | Complexation of silver and co-recovered metals with novel aza-crown ether macrocycles by electrospray ionization mass spectrometry. | Electrospray ionization mass spectrometry (ESI-MS) is used to evaluate the metal binding selectivities of an array of novel caged macrocycles for silver, gold, copper, nickel, zinc, iron, lead, manganese and alkali metal ions. It is found that five of the new compounds display silver selectivity, and their relative aff... |
14677769 | Improvement of dissolution and bioavailability of nitrendipine by inclusion in hydroxypropyl-beta-cyclodextrin. | A significant increase in solubility and dissolution rate of nitrendipine, a slightly soluble calcium channel blocker, was achieved by inclusion complexation with hydroxypropyl-beta-cyclodextrin (HP-beta-CD). The inclusion complex was prepared by solvent evaporation method and characterized by phase solubility method, ... |
14671791 | NMR-based methods and strategies for drug discovery. | Nuclear Magnetic Resonance (NMR) spectroscopy has long been a favourite tool of chemists interested in host-guest systems because it permits access to a wealth of information about the molecular recognition reaction. NMR has evolved dramatically in the last 15 years and, in parallel with the development of NMR methods ... |
14668378 | Genetic modifiers of tauopathy in Drosophila. | In Alzheimer's disease and related disorders, the microtubule-associated protein Tau is abnormally hyperphosphorylated and aggregated into neurofibrillary tangles. Mutations in the tau gene cause familial frontotemporal dementia. To investigate the molecular mechanisms responsible for Tau-induced neurodegeneration, we ... |
14668373 | Study of dosage compensation in Drosophila. | Using a sensitive RT-QPCR assay, we analyzed the regulatory effects of sex and different dosage compensation mutations in Drosophila. To validate the assay, we showed that regulation for several genes indeed varied with the number of functional copies of that gene. We then confirmed that dosage compensation occurred fo... |
14664400 | Translational isomerism and dynamics in multi-hydroquinone derived porphyrin [2]- and [3]-catenanes. | A series of porphyrins strapped with polyether chains containing two or three 1,4-dioxybenzene units has been synthesised with a view to the production of porphyrin-containing [2] and [3]catenanes, where the porphyrin is strapped between ortho-positions of 5,15-(meso)-diaryl groups, and is interlinked with the bipyridi... |
14664387 | Synthesis of sparteine-like chiral diamines and evaluation in the enantioselective lithiation-substitution of N-(tert-butoxycarbonyl)pyrrolidine. | Three chiral diamines were synthesised and evaluated as sparteine surrogates in the lithiation-substitution of N-(tert-butoxycarbonyl)pyrrolidine. The synthesis and attempted resolution of sparteine-like diamines [(1S*,2R*,8R*)-10-methyl-6,10-diazatricyclo[6.3.1.0(2,6)]dodecane and (1S*,2R*,9R*)-11-methyl-7,11-diazatri... |
14664381 | Oligonucleotide duplexes containing N8-glycosylated 8-aza-7-deazaguanine and self-assembly of 8-aza-7-deazapurines on the nucleoside and the oligomeric level. | The 8-aza-7-deazaguanine N8-(2'-deoxy-beta-D-ribofuranoside) (1) was synthesized, converted into the phosphoramidite 4 and incorporated into oligonucleotides. Nucleoside 1 forms stable base pairs with 2'-deoxy-5-methylisocytidine in DNA with antiparallel chain orientation (aps) and with 2'-deoxycytidine in duplexes wit... |
14664337 | Enhancement of dissolution and oral bioavailability of gliquidone with hydroxy propyl-beta-cyclodextrin. | The virtual insolubility of gliquidone in water results in poor wettability and dissolution characteristics, which may lead to a variation in bioavailability. To improve these characteristics of gliquidone, binary systems with hydroxypropyl-beta-cyclodextrin (HP-beta-CD) were prepared by classical methods such as physi... |
14656145 | Development of a segmented model for a continuous electrophoretic moving bed enantiomer separation. | With the recent demonstration of a continuous electrophoretic "moving bed" enantiomer separation at mg/h throughputs, interest has now turned to scaling up the process for use as a benchtop pharmaceutical production tool. To scale the method, a steady-state mathematical model was developed that predicts the process res... |
14656144 | Optimization of cyclodextrin glycosyltransferase production from Klebsiella pneumoniae AS-22 in batch, fed-batch, and continuous cultures. | Production of a novel cyclodextrin glycosyltransferase (CGTase) from Klebsiella pneumoniae AS-22 strain, which converts starch predominantly to alpha-CD at high conversion yields, in batch, fed-batch, and continuous cultures, is presented. In batch fermentations, optimization of different operating parameters such as t... |
14643120 | Azoospermia in patients heterozygous for a mutation in SYCP3. | <h4>Background</h4>Many cases of male infertility are diagnosed as idiopathic, reflecting poor understanding of the molecular defects underlying the abnormality. As more gene mutations causing male infertility in mice become known, there are improving prospects that knowledge about the genetic aetiology of human male i... |
14645494 | Adenosinergic protection of dopaminergic and GABAergic neurons against mitochondrial inhibition through receptors located in the substantia nigra and striatum, respectively. | Mitochondrial dysfunction may contribute to dopaminergic (DAergic) cell death in Parkinson's disease and GABAergic cell death in Huntington's disease. In the present work, we tested whether blocking A1 receptors could enhance the damage to DAergic and GABAergic neurons caused by mitochondrial inhibition, and whether bl... |
14645477 | Gene profile of electroconvulsive seizures: induction of neurotrophic and angiogenic factors. | Electroconvulsive seizure therapy (ECS) is a clinically proven treatment for depression and is often effective even in patients resistant to chemical antidepressants. However, the molecular mechanisms underlying the therapeutic efficacy of ECS are not fully understood. One theory that has gained attention is that ECS a... |
14648822 | Evaluation of the metal binding properties of a histidine-rich fusogenic peptide by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry. | Electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICRMS) was used to investigate metal ion interactions of the 18 amino acid peptide fragment B18 (LGLLLRHLRHHSNLLANI), derived from the membrane-associated protein bindin. The peptide sequence B18 represents the minimal membrane-b... |
14644701 | Initial RNA expression in human monocytes after multiple injury: a screening pilot study on potentially trauma-sensitive factors by using the microarray-technique. | <h4>Background</h4>Pathological affection of the immune system is one of the initiating mechanisms for the induction of multiple organ failure (MOF) in patients suffering from multiple injuries. Potential responsible intracellular mechanisms such as initial monocyte mRNA expression of specific mediators remain poorly s... |
14652069 | Cooperativity, partially bound states, and enthalpy-entropy compensation. | Efforts to develop a quantitative understanding of molecular recognition rely on the additivity of individual intermolecular interactions, and cooperativity represents one of the major potential stumbling blocks. A chemical double-mutant cycle has been used to experimentally measure cooperativity between functional gro... |
14649918 | Hindered fluorescence quenching in an insulated molecular wire. | A [3]rotaxane 2 within 1(2) consisting of an anionic phenylene ethynylene dumbbell 2(4-) threaded through two cationic cyclophanes 1(2+) has been prepared using aqueous Glaser coupling. Stern-Volmer analysis of the fluorescence quenching using three different electron-acceptors (methyl viologen 13(2+), dipropyl-4,4'-bi... |
14649917 | Formation of gold-like metal-lustrous inclusion crystals from 1-phenyl-2,5-bis[5-(tricyanoethenyl)-2-thienyl]pyrrole host and an electron-donating aromatic guest. | A novel pi-conjugated organic compound, 1-phenyl-2,5-bis[5-(tricyanoethenyl)-2-thienyl]pyrrole, which bears two powerful electron-withdrawing tricyanoethenyl substitutents, readily yielded gold-like metal-lustrous inclusion crystals with a series of aromatic guest molecules such as toluene, p-xylene, anisole, dimethoxy... |
14649834 | The effect of ruthenium(III) chloride on the formation of protonated parent ions in electrospray mass spectrometry. | We report the use of RuCl3 as an "alkali metal sponge". This is a general and highly efficient method for generating protonated parent ions for a variety of compounds that usually do not show this ion in electrospray mass spectrometry. This technique is demonstrated to be highly useful in "cleaning up" spectra from mul... |
14649805 | Dynamic combinatorial libraries of metalloporphyrins: templated amplification of disulfide-linked oligomers. | Disulfide-linked cyclic porphyrin oligomers from dimer to tetramer can be selected and amplified virtually quantitatively from a dynamic combinatorial library using bis-thiol substituted zinc(II) porphyrin units with appropriate amine donor templates. |
14649803 | Structural characterisation of the first mononuclear bismuth porphyrin. | A single carboxylate picket bismuth porphyrin has been characterised in the solid state as the first instance of a non-dimeric structure; the carboxylate picket, bent over the macrocycle, is coordinated to the bismuth, inducing a significant distortion of the porphyrin core. |
14649801 | Aggregation of metallo-supramolecular architectures by metallo-assembled hydrogen bonding sites. | Metal-ligand interactions are used not only to design metallo-supramolecular architectures but also to assemble multiple hydrogen bond sites at the periphery of these architectures. The hydrogen bond sites aggregate the architectures into polymeric arrays with the selection of anion determining whether this is self H-b... |
14649799 | Vapour diffusion hydrolysis of a self-assembled silylated organogel, the OG-HG transcription process: a new way to cast and handle fluorescent silsesquioxane. | A new method of hydrolysis-polycondensation of silsesquioxanes, the OG-HG (Organo Gel-Hybrid Gel or Organised Gel-Hydrolysed Gel) process allows the transcription of the supramolecular architecture of organogels to corresponding hybrid silsesquioxanes. |
14649798 | Carbonate and oxalate dianions as prolific hydrogen-bond acceptors in supramolecular assembly. | In the new inclusion compound [(C2H5)4N+]2 x CO3(2-) x 7(NH2)2CS, the carbonate ion is surrounded by twelve convergent NH donor groups from six thiourea molecules to form a hydrogen-bonded aggregate shaped like two concave three-leaved propellers sharing a common core, whereas in [(n-C3H7)4N+]2 x C2O4(2-) x 4(NH2)2CS t... |
14649712 | Enhanced desorption of phenanthrene from soils using hydroxypropyl-beta-cyclodextrin: experimental results and model predictions. | Objective of this study was to evaluate the effects of hydroxypropyl-beta-cyclodextrin (HPCD) on the removal of phenanthrene from solid phase. Batch tests for the phenanthrene distribution between aqueous and solid phase were conducted in the presence of HPCD. Column tests and numerical simulations were conducted to ev... |
14649501 | Contact deformation of liposome in the presence of osmosis. | The role of osmotic pressure on the geometry of adherent liposome remains an intricate question in the mechanics of supramolecular structures. In this study, confocal reflection interference contrast microscopy in combination with cross-polarized microscopy was applied to probe the geometry of deformed liposome on fuse... |
14640449 | Enantiomer separation of miconazole by capillary electrophoresis with dual cyclodextrin systems. | A cyclodextrin-modified micellar capillary electrophoretic method (MECC) was developed using mixtures of beta, cyclodextrins (beta-CD) and mono-3-O-phenylcarbamoyl-beta-CD as chiral additives for the chiral separation of miconazole with the dual CDs systems. The enantiomers were resolved using a running buffer of 50 mm... |
14636582 | Direct binding of the PDZ domain of Dishevelled to a conserved internal sequence in the C-terminal region of Frizzled. | The cytoplasmic protein Dishevelled (Dvl) and the associated membrane-bound receptor Frizzled (Fz) are essential in canonical and noncanonical Wnt signaling pathways. However, the molecular mechanisms underlying this signaling are not well understood. By using NMR spectroscopy, we determined that an internal sequence o... |
14629183 | Total synthesis of dendroamide a: oxazole and thiazole construction using an oxodiphosphonium salt. | The total synthesis of dendroamide A (1), a multidrug-resistance reversing bistratamide-type peptide-derived macrocycle, has been accomplished in 19% yield. Fmoc-protected amino acids were condensed into appropriately protected dipeptides which were treated with bis(triphenyl)oxodiphosphonium trifluoromethanesulfonate ... |
14629173 | Multiple conformations of benzil in resorcinarene-based supramolecular host matrixes. | Six supramolecular complexes incorporating benzil as a guest, CMCR*bipy*benzil (alpha) 1 (CMCR = C-methylcalix[4]resorcinarene), CMCR*bipy*benzil (beta) 2, CMCR*2bpe*benzil*ethanol 3 (bpe = trans-1,4-bis(pyridyl)ethylene), CMCR*2bpe*benzil*2H2O 4, CMCR.2bpeh*benzil*ethanol 5 (bpeh = bis-(1-pyridin-4-yl-ethylidene)-hydr... |
14629172 | Functionalization of cyclodextrins via reactions of 2,3-anhydrocyclodextrins. | Three types of reactions of 2,3-anhydro-beta-cyclodextrins, namely nucleophilic ring-opening, reduction to 2-enopyranose, and reduction to 3-deoxypyranose, have been investigated to regio- and stereoselectively functionalize the secondary face of beta-cyclodextrin. Upon treatment with various nucleophiles, both 2,3-man... |
14629137 | Synthesis and characterization of cationic iodonium macrocycles. | A synthetic strategy for the high-yield preparation of iodonium containing macrocycles such as rhomboids, a square, and a pentagon is described, with the long-term objective of preparing iodonium compounds for potential molecular electronics applications. Two cationic rhomboid shaped molecules were prepared for the fir... |
14629133 | A rational study of crystal engineering of supramolecular assemblies of 1,2,4,5-benzenetetracarboxylic acid. | Supramolecular assemblies of 1,2,4,5-benzenetetracarboxylic acid, 1, with aza donor molecules such as 1,10-phenanthroline, 2, 1,7-phenanthroline, 3, phenazine, 4, 4-(N,N-dimethylamino)pyridine, 5, 1,2-bis(4-pyridyl)ethene, 6, and 1,2-bis(4-pyridyl)ethane, 7, have been synthesized and characterized by single-crystal X-r... |
14630515 | Electrostatic potential on human leukocyte antigen: implications for putative mechanism of chronic beryllium disease. | The pathobiology of chronic beryllium disease (CBD) involves the major histocompatibility complex class II human leukocyte antigen (HLA). Although occupational exposure to beryllium is the cause of CBD, molecular epidemiologic studies suggest that specific (Italic)HLA-DPB1(/Italic) alleles may be genetic susceptibility... |
14627409 | Enhanced photodecarboxylation of an aryl ester in polyethylene films. | [reaction: see text] Photodecarboxylation is the exclusive photoreaction of 2,4,6-trimethylphenyl (S)-2-methylbutanoate in unstretched high-density polyethylene films. The sole product, (S)-1-(2-methylpropyl)-2,4,6-trimethylbenzene, is formed with complete retention of stereochemistry. In other polyethylene films, orga... |
14627389 | A pH switch in supramolecular polymeric capsules. | [structure: see text] A switchable, supramolecular polymer is introduced which is held together through hydrogen bonding and reversibly precipitates-redissolves upon subtle pH control. Precipitating, it entraps and stores guest molecules within the self-assembling capsules incorporated within the polymeric chain. |
14627385 | New oxazole-based peptidomimetics: useful building blocks for the synthesis of orthogonally protected macrocyclic scaffolds. | [structure: see text] The synthesis of a new family of densely functionalized oxazole-containing amino acids is described. These building blocks were employed for preparing macrocycles containing Lys and Glu residues by a combination of solid- and solution-phase synthesis. The resulting structures are presented as orth... |
14624611 | Theoretical study of a new DNA structure: the antiparallel Hoogsteen duplex. | The structure of a new form of duplex DNA, the antiparallel Hoogsteen duplex, is studied in polyd(AT) sequences by means of state-of-the-art molecular dynamics simulations in aqueous solution. The structure, which was found to be stable in all of the simulations, has many similarities with the standard Watson-Crick dup... |
14624601 | The effect of global compaction on the local secondary structure of folded dendrimers. | The effect of nonlocal interactions on the local structural propensities of folded dendrimers was evaluated in this work by comparing, under identical conditions, the conformational properties of isomeric dendrimers differing in their global packing efficiency. Accordingly, a modular synthesis of two series of dendrime... |
14624599 | Correspondence between molecular functionality and crystal structures. Supramolecular chemistry of a family of homologated aminophenols. | The crystal structures and packing features of a family of 13 aminophenols, or supraminols, are analyzed and correlated. These compounds are divided into three groups: (a) compounds 1-5 with methylene spacers of the general type HO-C6H4-(CH2)n-C6H4-NH2 (n = 1 to 5) and both OH and NH2 in a para position; (b) compounds ... |
14624595 | Ion pairing in fast-exchange host-guest systems: concentration dependence of apparent association constants for complexes of neutral hosts and divalent guest salts with monovalent counterions. | An equilibrium treatment of complexation of neutral hosts with dicationic guests having univalent counterions includes two possible modes: (1) dissociation of the ion pair prior to interaction of the free dication with the host to produce a complex that is not ion paired and (2) direct complexation of the ion pair to p... |
14624582 | Molecular recognition of protein surfaces: high affinity ligands for the CBP KIX domain. | Potent and specific inhibitors of protein.protein interactions have potential both as therapeutic compounds and biological tools, yet discovery of such molecules remains a challenge. Our laboratory has recently described a strategy, called protein grafting, for the identification of miniature proteins that bind protein... |
14624554 | Orthogonal self-assembly of low molecular weight hydrogelators and surfactants. | The concurrent self-assembly of new 1,3,5-trisamide-cyclohexane-based low molecular weight hydrogelators and various surfactants in water leads to the formation of self-assembled fibrillar networks with encapsulated micelles. This prototype system presents an example of orthogonal self-assembly, that is, the independen... |
14624551 | Parallel molecular computations of pairwise exclusive-or (XOR) using DNA "string tile" self-assembly. | Self-assembling DNA nanostructures are an efficient means of executing parallel molecular computations. However, previous experimental demonstrations of computations by DNA tile self-assembly only allowed for one set of distinct input to be processed at a time. Here, we report the multibit, parallel computation of pair... |
14624536 | Multiple intermolecular interaction modes of positively charged residues with adenine in ATP-binding proteins. | Adenosine 5'-triphosphate (ATP) plays an essential role in all forms of life. Molecular recognition of ATP in ATP-binding proteins is a subject of great importance for understanding enzymatic mechanisms and for drug design. We have carried out a large-scale data mining of the Protein Data Bank (PDB) to analyze molecula... |
14625695 | Conformational constraints on side chains in protein residues increase their information content. | Like all other complex biological systems, proteins exhibit properties not seen in free amino acids (i.e., emergent properties). The present investigation arose from the deduction that proteins should offer a good model to approach the reverse phenomenon, namely top-down constraints experienced by protein residues comp... |
14625687 | Canonical protein inhibitors of serine proteases. | Serine proteases and their natural protein inhibitors are among the most intensively studied protein complexes. About 20 structurally diverse inhibitor families have been identified, comprising alpha-helical, beta sheet, and alpha/beta proteins, and different folds of small disulfide-rich proteins. Three different type... |
14625686 | Pharmacologically active spider peptide toxins. | Advances in mass spectrometry and peptide biochemistry coupled to modern methods in electrophysiology have permitted the isolation and identification of numerous novel peptide toxins from animal venoms in recent years. These advances have also opened up the field of spider venom research, previously unexplored due to m... |
14625683 | Lytic transglycosylases in macromolecular transport systems of Gram-negative bacteria. | The cell wall of Gram-negative bacteria is essential for the integrity of the bacterial cell but also imposes a physical barrier to trans-envelope transport processes in which DNA and/or proteins are taken up or secreted by complex protein assemblies. The presence of genes encoding lytic transglycosylases in macromolec... |
14625682 | Structure and morphogenesis of bacteriophage T4. | Bacteriophage T4 is one of the most complex viruses. More than 40 different proteins form the mature virion, which consists of a protein shell encapsidating a 172-kbp double-stranded genomic DNA, a 'tail,' and fibers, attached to the distal end of the tail. The fibers and the tail carry the host cell recognition sensor... |
14624638 | Polyplexes assembled with internally quaternized PAMAM-OH dendrimer and plasmid DNA have a neutral surface and gene delivery potency. | Interior tertiary amine groups of PAMAM-OH dendrimers (hydroxyl-terminated polyamidoamine, PAMAM) were modified by methylation to make these polymers have a more cationic character, which enabled electrostatic interaction between PAMAM-OH and plasmid DNA. A methylation reaction was dose-dependent, producing internally ... |
14624625 | Transferrin-containing, cyclodextrin polymer-based particles for tumor-targeted gene delivery. | Transferrin is a well-studied ligand for tumor targeting due to upregulation of transferrin receptors in numerous cancer cell types. Here, we report the development of a transferrin-modified, cyclodextrin polymer-based gene delivery system. The delivery system is comprised of a nanoparticle (formed by condensation of a... |
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