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15227639 | Structural basis of light chain amyloidogenicity: comparison of the thermodynamic properties, fibrillogenic potential and tertiary structural features of four Vlambda6 proteins. | Primary (AL) amyloidosis results from the pathologic deposition of monoclonal light chains as amyloid fibrils. Studies of recombinant-derived variable region (VL) fragments of these proteins have shown an inverse relationship between thermodynamic stability and fibrillogenic potential. Further, ionic interactions withi... |
15227638 | A novel mammalian display system for the selection of protein-protein interactions by decoy receptor engagement. | The emerging field of proteomics has created a need for new high-throughput methodologies for the analysis of gene products. An attractive approach is to develop systems that allow for clonal selection of interacting protein pairs from large molecular libraries. In this study, we have characterized a novel approach for... |
15227637 | Advances in membrane receptor screening and analysis. | During the last decade there has been significant progress in the development of analytical techniques for the screening of ligand binding to membranes and membrane receptors. This review focuses on developments using label-free assays that facilitate ligand-membrane-receptor screening without the need for chemical-, b... |
15227636 | The influence of intercalator binding on DNA triplex stability: correlation with effects on A-tract duplex structure. | The triplex form of DNA is of interest because of a possible biological role as well as the potential therapeutic use of this structure. In this paper the stabilizing effects of two intercalating drugs, ethidium and the quinoxaline derivative 9-OH-B220, on DNA triplexes have been studied by thermal denaturation measure... |
15226391 | Localization and regulation of SR-BI in membrane rafts of HepG2 cells. | The scavenger receptor class B, type I (SR-BI) mediates cholesteryl esters (CE) selective uptake from low density lipoprotein (LDL) and high-density lipoprotein (HDL) particles. In a number of tissues expressing caveolin, SR-BI is localized in caveolae. We show using detergent-free sucrose gradients that SR-BI is found... |
15099193 | Long-chain saturated fatty acids induce annexin II translocation to detergent-resistant membranes. | DRM (detergent-resistant membranes), which are resistant to solublization by non-ionic detergents, have been demonstrated to be involved in many key cell functions such as signal transduction, endocytosis and cholesterol trafficking. Covalent modification of proteins by fatty acylation has been proposed to be an import... |
15084146 | Crystal structure of NS-134 in complex with bovine cathepsin B: a two-headed epoxysuccinyl inhibitor extends along the entire active-site cleft. | The crystal structure of the inhibitor NS-134 in complex with bovine cathepsin B reveals that functional groups attached to both sides of the epoxysuccinyl reactive group bind to the part of active-site cleft as predicted. The -Leu-Pro-OH side binds to the primed binding sites interacting with the His110 and His111 res... |
15224342 | Rational synthesis of multicyclic bis[2]catenanes. | Bis-loop tetraurea calix[4]arene 6 has been prepared by acylation of the wide-rim calix[4]arene tetraamine 1 with the activated bis(urethane) 8 under dilution conditions. Similarly the bis(Boc-protected) tetraamine 2 is converted into the mono-loop derivative 3 which after deprotection and acylation gives the bisalkeny... |
15224335 | Supramolecular complexation of alkali cations through mechanochemical reactions between crystalline solids. | The organometallic zwitterion [Co(III)(eta(5)-C(5)H(4)COOH)(eta(5)-C(5)H(4)COO)] reacts quantitatively as a solid polycrystalline phase with a number of crystalline alkali salts MX (M = K(+), Rb(+), Cs(+), NH(4) (+); X = Cl(-), Br(-), I(-), PF(6)(-), although not in all cation/anion permutations) to afford supramolecul... |
15224331 | Robust core-shell supramolecular assemblies based on cationic vesicles and ring-shaped [Mo154] polyoxomolybdate nanoclusters: template-directed synthesis and characterizations. | Substantial progress has been made recently in extending the supramolecular assembly of biomimetic structures to vesicle-based sophisticated nanocomposites and mesostructures. We report herein the successful preparation of unilamellar surfactant vesicles coated with a monolayer of ring-shaped [Mo(154)] polyoxometalate ... |
15224325 | Dissection of human tropoelastin: solution structure, dynamics and self-assembly of the exon 5 peptide. | The elastic properties of elastin have essentially been discussed in terms of dominant entropic components, with questions still remaining about whether the basic mechanism is compatible with the classical theory of rubber elasticity. A better understanding of the structure-function relationships in terms of the protei... |
15224324 | Novel supramolecular isomerism in coordination polymer synthesis from unsymmetrical bridging ligands: solvent influence on the ligand placement orientation and final network structure. | The assembly of Co(NCS)(2) with 1-methyl-1'-(3-pyridyl)-2-(4-pyridyl)ethene (L(1)) exhibits a novel supramolecular isomerism of [Co(L(1))(2)(NCS)(2)](infinity) caused by different placement orientation of L(1) around metal centers. The reaction in MeOH/H(2)O and EtOH/H(2)O resulted in a double chain structure of 1, and... |
15224323 | Organic spin clusters: annelated macrocyclic polyarylmethyl polyradicals and a polymer with very high spin S=6-18. | Synthesis and magnetic studies of annelated macrocyclic polyradicals and a related high-spin polymer with macrocyclic repeat units are described. Polyarylmethyl polyether precursors to the polyradicals and the related polymer are prepared by using Negishi cross-coupling of difunctionalized calix[4]arene-based macrocycl... |
15224322 | Correlation between host-guest binding and host amplification in simulated dynamic combinatorial libraries. | We present a versatile computer model of diverse dynamic combinatorial libraries, and examine how molecular recognition between library members and a template can be used to amplify the best binders. The correlation between host-guest binding and amplification was examined for a set of 50 libraries with >300 components... |
15223140 | Calorimetric vs. van't Hoff binding enthalpies from isothermal titration calorimetry: Ba2+-crown ether complexation. | The 1:1 complexation reaction between Ba(2+) and 18-crown-6 ether is re-examined using isothermal titration calorimetry (ITC), with the goal of clarifying previously reported discrepancies between reaction enthalpies estimated directly (calorimetric) and indirectly, from the temperature dependence of the reaction equil... |
15220076 | The influence of small oligosaccharides on the immune system. | In this study, oligosaccharides known to enhance the synthesis of penicillin by Penicillium chrysogenum have been presented to human immune cells and their effect measured. In addition a range of commercially available oligosaccharides have been tested. Results obtained indicate that oligosaccharides with a degree of p... |
15215517 | De novo proteins from designed combinatorial libraries. | Combinatorial libraries of de novo amino acid sequences can provide a rich source of diversity for the discovery of novel proteins with interesting and important activities. Randomly generated sequences, however, rarely fold into well-ordered proteinlike structures. To enhance the quality of a library, features of rati... |
15213431 | Model building of a protein-protein complexed structure using saturation transfer and residual dipolar coupling without paired intermolecular NOE. | For understanding the precise mechanisms of molecular recognition of proteins, three-dimensional structural analyses of the protein-protein complexes are essential. For this purpose, a new method to reveal complex structures was developed with the assistance of saturation transfer (SAT) and residual dipolar coupling (R... |
15213427 | Uniform and residue-specific 15N-labeling of proteins on a highly deuterated background. | A general method for stable-isotope labeling of large proteins is introduced and applied for studies of the E. coli GroE chaperone proteins by solution NMR. In addition to enabling the residue-specific (15)N-labeling of proteins on a highly deuterated background, it is also an efficient approach for uniform labeling. T... |
15207552 | Mathematical evaluation of in vitro release profiles of hydroxypropylmethylcellulose matrix tablets containing carbamazepine associated to beta-cyclodextrin. | The release kinetics of carbamazepine (CBZ) either complexed or physically mixed with beta-cyclodextrin (betaCD) from hydroxypropylmethylcellulose (HPMC) matrix tablets was investigated using different mathematical equations. The model-dependent approach was compared to the utilization of fit factors. Notwithstanding d... |
15207547 | In vitro permeation studies comparing bovine nasal mucosa, porcine cornea and artificial membrane: androstenedione in microemulsions and their components. | The components of a carrier formulation can interact with an added drug as well as with the membrane surface they were applied on. Therefore, they can influence permeability of the membrane and permeation of the drug. The particular membrane structure might lead to different drug permeation out of one and the same carr... |
15207542 | Degradation of raw or film-incorporated beta-cyclodextrin by enzymes and colonic bacteria. | beta-cyclodextrin (beta-CD) is a suitable excipient for peroral use, which improves the solubility of lipophilic drugs, as well as for colon-specific drug release when it is mixed with coating polymers. The first aim of this work was to examine the suitability of various enzymes as a simple in vitro model for the glyco... |
15207537 | Influence of cellulose ether polymers on ketoprofen release from hydrophilic matrix tablets. | The present work reports the study of different ketoprofen:excipient formulations, in order to determine the effect of the polymer substitution and type of diluent on the drug-release mechanism. Substituted cellulose-methylcellulose, hydroxypropylcellulose and hydroxypropylmethylcellulose were used as polymers, while l... |
15203330 | A fusion protein expression analysis using surface plasmon resonance imaging. | A surface plasmon resonance (SPR) imaging system was constructed and used to detect the affinity-tagged recombinant proteins expressed in Escherichia coli. With regards to model proteins, the hexahistidine-ubiquitin-tagged human growth hormone (His(6)-Ub-hGH), glutathione S-transferase-tagged human interleukin-6 (GST-h... |
15196580 | Complexation of the sunscreen agent, phenylbenzimidazole sulphonic acid with cyclodextrins: effect on stability and photo-induced free radical formation. | The interaction between the sunscreen agent, phenylbenzimidazole sulphonic acid (PBSA) and hydrophilic alpha-, beta-, and gamma-cyclodextrin derivatives was investigated under acidic conditions (pH 4.0) by phase-solubility analysis. Among the available cyclodextrins, hydroxypropyl-beta-cyclodextrin (HP-beta-CD) and ran... |
15186852 | A study of the stability of tri(glucosyloxyphenyl)chlorin, a sensitizer for photodynamic therapy, in human colon tumoural cells: a liquid chromatography and MALDI-TOF mass spectrometry analysis. | Asymmetrical glycoconjugated tetrapyrrolic macrocycles are under study as efficient sensitizers for photodynamic therapy (PDT). In this context, tri(meta-O-beta-glucopyranosyloxyphenyl)chlorin [TPC(m-O-Glu)(3)] 2a/3a was found to be four times more photoactive in vitro than Foscan. In a further study of this interestin... |
15182810 | Towards integrated ADME prediction: past, present and future directions for modelling metabolism by UDP-glucuronosyltransferases. | Undesirable absorption, distribution, metabolism, excretion (ADME) properties are the cause of many drug development failures and this has led to the need to identify such problems earlier in the development process. This review highlights computational (in silico) approaches that have been used to identify the charact... |
15178297 | Multilayer vesicles and vesicle clusters formed by the fullerene-based surfactant C60(CH3)5K. | The self-assembly behavior of a fullerene-based surfactant, C60(CH3)5K, in water was studied using a combination of static and dynamic light scattering, as well as transmission electron microscopy, and compared to that of the compound C60(C6H5)5K. Both fullerene surfactant systems spontaneously assemble into large vesi... |
15176056 | NMR spectroscopic characterization of metoprolol/cyclodextrin complexes in aqueous solution: cavity size dependency. | The inclusion complex formation of a water-soluble beta(1)-selective adrenoreceptor antagonist Metoprolol (Met) with alpha-cyclodextrin (alpha-CyD), beta-cyclodextrin (beta-CyD), gamma-cyclodextrin (gamma-CyD), and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) in aqueous solution was studied by ultraviolet (UV), circ... |
15171934 | Simultaneous determination of vigabatrin and amino acid neurotransmitters in brain microdialysates by capillary electrophoresis with laser-induced fluorescence detection. | Capillary electrophoresis with laser-induced fluorescence detection (CE-LIFD) coupled to in vivo microdialysis sampling was used in order to monitor simultaneously a drug and several neurotransmitters in the brain extracellular fluid. Determination of the antiepileptic drug vigabatrin and the amino acid neurotransmitte... |
15171933 | Interval immobilization technique for recognition toward a highly hydrophilic cyanobacterium toxin. | A novel adsorption medium containing selective molecular recognition site for one of the powerful cyanobacterium toxins, Cylindrospermopsin (CYN) was developed using a special technique, namely interval immobilization technique. The adsorption medium was prepared using molecular assembly derived from an alternative-tem... |
15170592 | Selective human enterovirus and rhinovirus inhibitors: An overview of capsid-binding and protease-inhibiting molecules. | The absence of effective vaccines for most viral infections highlights an urgent necessity for the design and development of effective antiviral drugs. Due to the advancement in virology since the late 1980s, several key events in the viral life cycle have been well delineated and a number of molecular targets have bee... |
15142585 | Synthesis and photoluminescence study of molecularly imprinted polymers appended onto CdSe/ZnS core-shells. | The Photoluminescence of quantum dots have been found to be a useful tool for the detection of small to medium sized analyte molecules in a host-guest environment. By the incorporation of quantum dots into molecularly imprinted polymers, which can offer shape and selectivity, the former can respond by quenching the pho... |
15142595 | Amperometric enzyme electrodes for aerobic and anaerobic glucose monitoring prepared by glucose oxidase immobilized in mixed ferrocene-cobaltocenium dendrimers. | The enzyme glucose oxidase (GOx) has been immobilized electrostatically onto carbon and platinum electrodes modified with mixed ferrocene-cobaltocenium dendrimers. The ferrocene units have been used successfully as mediators between the GOx and the electrode under anaerobic conditions. In experiments carried out in the... |
15446714 | Identification by gas chromatography-mass spectrometry of the volatile organic compounds emitted from the wood-rotting fungi Serpula lacrymans and Coniophora puteana, and from Pinus sylvestris timber. | Volatile organic compounds (VOCs) emitted by two wood-rotting basidiomycete fungi, Serpula lacrymans (dry rot fungus) and Coniophora puteana (cellar fungus), and the timber of Pinus sylvestris (Scots pine), were identified. Several volatile collection techniques were employed including dichloromethane solvent extractio... |
15446584 | A pathogenic peripherin gene mutation in a patient with amyotrophic lateral sclerosis. | Peripherin is a neuronal intermediate filament protein that is expressed chiefly in motor neurons and other nerve cells that project into the peripheral nervous system. Transgenic mice that over-express peripherin develop motor neuron degeneration, suggesting that mutations in peripherin could contribute to the develop... |
15354567 | High-performance liquid chromatographic enantioseparations on capillary columns containing monolithic silica modified with cellulose tris(3,5-dimethylphenylcarbamate). | Monolithic capillary columns containing native silica gel were modified with cellulose tris(3,5-dimethylphenylcarbamate) (CDMPC) and used for enantioseparations in capillary liquid chromatography. The method adopted for in situ enantioselective modification of monolithic fused silica capillary columns by coating with C... |
15354553 | Preparation and HPLC applications of rigid macroporous organic polymer monoliths. | Rigid porous polymer monoliths are a new class of materials that emerged in the early 1990s. These monolithic materials are typically prepared using a simple molding process carried out within the confines of a closed mold. For example, polymerization of a mixture comprising monomers, free-radical initiator, and poroge... |
15232003 | Contiguous stereogenic quaternary carbons: a daunting challenge in natural products synthesis. | One element of structure that invariably increases the difficulty of a chemical synthesis is the presence in the target molecule of contiguous all-carbon quaternary stereocenters. This Perspective will examine the most useful transformations and strategies devised recently for directly assembling this structural unit. |
15231999 | Total synthesis of the marine cyanobacterial cyclodepsipeptide apratoxin A. | A total synthesis of apratoxin A was developed. Apratoxin A, isolated from Lyngbya spp. cyanobacteria, is representative of a growing class of marine cyanobacterial cyclodepsipeptides wherein discrete polypeptide and polyketide domains are merged by ester and amide or amide-derived linkages. In the apratoxins, the N te... |
15311845 | Supercritical carbon dioxide extraction of chamomile flowers: extraction efficiency, stability, and in-line inclusion of chamomile-carbon dioxide extract in beta-cyclodextrin. | The extraction of chamomile flowers using supercritical carbon dioxide was investigated with respect to extraction efficiency and compared with solvent extraction. The stability of matricine, a sensitive constituent of the essential oil of chamomile, in these extracts was studied during storage at different temperature... |
15298389 | Photochromism of novel molybdate/alkylamine composite thin films. | Novel inorganic/organic composite films of molybdates with photochromic properties have been prepared by self-assembly using alkylammonium ions as a supramolecular template. Both 1-hexadecylammonium/polyoxomolybdate (C16-Mo) and 1-octadecylammonium/polyoxomolybdate (C18-Mo) composite films have been successfully fabric... |
15298387 | Amorphous silica as a versatile supermolecular ligand for Ni(II) amine complexes: toward interfacial molecular recognition. | Selective adsorption of Ni(II) amine complexes used as precursors for supported catalysts was studied on amorphous silica surfaces. The nature of the adsorption sites was probed by [Ni(en)(dien) (H2O)]2+, [Ni(en)2(H2O)2]2+, and [Ni(dien)(H2O)3]2+ (en = ethylenediamine, dien = diethylenetriamine), which respectively con... |
15296388 | High-performance liquid chromatographic enantioseparations on monolithic silica columns containing a covalently attached 3,5-dimethylphenylcarbamate derivative of cellulose. | Covalent immobilization of 3,5-dimethylphenylcarbamate derivative of cellulose was performed in situ onto native silica monoliths cladded in a 50 mm x 4.6 mm polyether ether ketone high-performance liquid chromatographic (HPLC) column. The covalent attachment of cellulose derivative in the range of 16-19% (w/w) was per... |
15293241 | Sulfotransferases: structure, mechanism, biological activity, inhibition, and synthetic utility. | The sulfonation (also known as sulfurylation) of biomolecules has long been known to take place in a variety of organisms, from prokaryotes to multicellular species, and new biological functions continue to be uncovered in connection with this important transformation. Early studies of sulfotransferases (STs), the enzy... |
15282050 | Phosphorescence properties of p-aminobenzoic acid immobilized on a nylon membrane. | The properties of nylon as a new material for obtaining room-temperature phosphorescence from p-aminobenzoic acid (PABA) have been investigated. Although PABA shows native phosphorescence when adsorbed on a nylon membrane, a significant improvement in both sensitivity and limit of detection is achieved in the presence ... |
15282048 | Thermodynamics of complexation of dimethyl esters of tere-, iso-, and phthalic acids with alpha- and beta-cyclodextrins. | Thermodynamics of inclusion of alpha- and beta-cyclodextrins (CDs) with three diester precursors of polyesters, dimethyl terephthalate (DMT), dimethyl isophthalate (DMI), and dimethyl phthalate (DMP) were studied with different fluorescence spectroscopy techniques. The stoichiometry, association constants, and other th... |
15267238 | Macrocyclic diacylglycerol-bis-lactones as conformationally constrained analogues of diacylglycerol-lactones. Interactions with protein kinase C. | A series of macrocyclic diacylglycerol (DAG)-bis-lactones were investigated as extreme conformationally constrained analogues of DAG-lactones in order to seek more potent protein kinase C (PKC) ligands with higher binding affinities and less lipophilicity than previous compounds. The additional constraint achieved the ... |
15264848 | Polyphosphate ions encapsulated in oxothiomolybdate rings: synthesis, structure, and behavior in solution. | Cyclic oxothiomolybdates containing polyphosphate ions were prepared by simple reactions in aqueous medium of the corresponding polyphosphate ions and the cyclic precursor K(2)I(2)Mo(10)S(10)O(10)(OH)(10)(OH(2))(5).15H(2)O. K(5)[Cl(P(2)O(7)]Mo(12)S(12)O(12)(OH)(12)(H(2)O)(4)].22H(2)O (1) was isolated from concentrated ... |
15264831 | Water-soluble dendrimers as photochemical reaction media: chemical behavior of singlet and triplet radical pairs inside dendritic reaction cavities. | Water-soluble poly(alkyl aryl ether) dendrimers have been explored for their use as hosts of organic substrates in aqueous media. Prototypical photoreactions, namely, photo-Fries reaction of (a) 1-naphthyl benzoate and (b) 1-naphthyl phenyl ester and alpha-cleavage reaction of (a) dibenzyl ketones and (b) benzoin alkyl... |
15264827 | Mediation of conformationally controlled photodecarboxylations of chiral and cyclic aryl esters by substrate structure, temperature, pressure, and medium constraints. | An aryl alkanoate, 2,4,6-trimethylphenyl (S)-(+)-2-methylbutyrate, whose ester group has a chiral center alpha to the carbonyl carbon and in which photo-Fries rearrangements are blocked by methyl substituents, undergoes facile photodecarboxylation under a variety of conditions and with complete retention of configurati... |
15261577 | Intracellular antibodies for proteomics. | The intracellular antibody technology has many applications for proteomics studies. The potential of intracellular antibodies for the systematic study of the proteome has been made possible by the development of new experimental strategies that allow the selection of antibodies under conditions of intracellular express... |
15261569 | Binding proteins from alternative scaffolds. | The use of so-called protein scaffolds for the generation of novel binding proteins via combinatorial engineering has recently emerged as a powerful alternative to natural or recombinant antibodies. This concept requires an extraordinary stable protein architecture tolerating multiple substitutions or insertions at the... |
15263016 | Discs large (Dlg1) complexes in lymphocyte activation. | T cell antigen recognition involves the formation of a structured interface between antigen-presenting and T cells that facilitates the specific transmission of activating and desensitizing stimuli. The molecular machinery that organizes the signaling molecules and controls their disposition in response to activation r... |
15260507 | Origin, control, and application of supramolecular chirogenesis in bisporphyrin-based systems. | The rationalization of various aspects of the mechanism of chirality induction in supramolecular assemblies based upon the complexes formed between an ethane-linked bisoctaethylporphyrin and chiral ligands is described. The influence of various controlling factors such as bonding strength, host-guest steric interaction... |
15257603 | The first slipped pseudo-quadruple-decker complex of phthalocyanines. | The first slipped pseudo-quadruple-decker complex of phthalocyanines was formed unexpectedly upon treatment of the protonated double-decker SmIIIH(Pc)[Pc(alpha-OC4H9)8] with NaOH. The supramolecular structure contains two double-decker units linked by two sodium ions by an extremely rare coordination mode of phthalocya... |
15257602 | Syntheses and structures of Ag(I)-containing coordination polymers and Co(II)-containing supramolecular complex based on novel fulvene ligands. | Three new rigid conjugated fulvene ligands L1-L3 were synthesized. L1 and L3 have been prepared by an aroylation reaction of cyclohexyl-substituted cyclopentadienyl anions. L2 was prepared by the reaction of L1 with PhNHNH2 in hot enthanol. Six new coordination polymers, namely [Ag(C25H20N2O2)(ClO4)] x 3.5C6H6 (1), [Ag... |
15257598 | Binuclear copper(I) macrocycles synthesized via the weak-link approach. | The weak-link approach has been employed to synthesize a series of bimetallic Cu(I) macrocycles in high yield. Addition of phosphinoalkylether or -thioether ligands to [Cu(MeCN)4]PF6 produces "condensed" intermediates, [mu-(1,4-(PPh2CH2CH2X)2Y)2Cu2][PF6]2 (X = S, O; Y = C6H4, C6F4), containing strong P-Cu bonds and wea... |
15257591 | Attachment of an electron-withdrawing fluorophore to a cryptand for modulation of fluorescence signaling. | The laterally nonsymmetric aza cryptand synthesized by condensing tris(2-aminoethyl)amine (tren) with tris[2-[(3-(oxomethyl)phenyl)oxy]ethyl]mine readily forms mononuclear inclusion complexes with both transition- and main-group-metal ions. The fluorophore 7-nitrobenz-2-oxa-1,3-diazole is attached to one of the seconda... |
15257581 | Supramolecular and coordination polymer complexes supported by a tripodal tripyridine ligand containing a 1,3,5-triethylbenzene spacer. | By By combining a tripodal tripyridine ligand containing a 1,3,5-triethylbenzene spacer (L) with several divalent transition-metal chlorides, we have selectively prepared a capsule-type supramolecular complex, [PdII3(L)2Cl6] x 2H2O, and one-dimensional (1D) coordination polymer complexes, ([CuII(L)Cl2] x C2H5OH)n, ([Co... |
15257577 | An unusual 3D coordination polymer based on bridging interactions of the nucleobase adenine. | The first 3D coordination polymer containing a nucleobase as a bridging ligand, [[Cu2(mu-ade)4(H2O)2][Cu(ox)(H2O)]2 x approximately 14H2O]n (1), has been synthesized by reaction of adenine (Hade) with a basic solution of K2[Cu(ox)2] x 2H2O (ox = oxalato dianion). Compound 1 crystallizes in the trigonal space group R3 w... |
15258095 | Phase and antigenic variation in bacteria. | Phase and antigenic variation result in a heterogenic phenotype of a clonal bacterial population, in which individual cells either express the phase-variable protein(s) or not, or express one of multiple antigenic forms of the protein, respectively. This form of regulation has been identified mainly, but by no means ex... |
15255742 | 14-helical folding in a cyclobutane-containing beta-tetrapeptide. | The efficient synthesis of tetrapeptide 5 containing, in alternation, cyclobutane and beta-alanine residues is described. NMR experiments both at low temperature in CDCl(3) and at 298 K in DMSO-d(6) solutions show the contribution of a strong hydrogen bond in the folded major conformation of 5. Temperature coefficients... |
15255711 | A novel C3v-symmetrical calix[6](aza)cryptand with a remarkably high and selective affinity for small ammoniums. | The three-step synthesis of a calix[6]arene capped with a TAC unit is presented. The novel C(3v)-symmetrical calix[6](aza)cryptand displayed an exceptionally high affinity for small ammoniums. NMR and X-ray diffraction analyses demonstrated the formation of endo-complexes. These complexes are stabilized thanks to (i) h... |
15256503 | Topological domain structure of the Escherichia coli chromosome. | The circular chromosome of Escherichia coli is organized into independently supercoiled loops, or topological domains. We investigated the organization and size of these domains in vivo and in vitro. Using the expression of >300 supercoiling-sensitive genes to gauge local chromosomal supercoiling, we quantitatively mea... |
15250726 | Characterization, supramolecular assembly, and nanostructures of thiophene dendrimers. | We report the synthesis and characterization of dendritic thiophene derivatives with their unique supramolecular assembly into 2-D crystals, nanowires, and nanoparticle aggregates. The structure and size of the dendrons and dendrimers have been confirmed with various techniques, such as NMR, SEC, and MALDI-TOF-MS. The ... |
15250708 | Highly stereoselective prins cyclization of silylmethyl-substituted cyclopropyl carbinols to 2,4,6-trisubstituted tetrahydropyrans. | The homoallyl cation formed from a cyclopropyl carbinol that was vicinally substituted by a silylmethyl function underwent smooth Prins cyclization with aldehydes and ketones to form 2,4,6-trisubstituted tetrahydropyrans with very high stereoselectivity. |
15250701 | Rotaxanated conjugated sensory polymers. | Two highly emissive conjugated polymers with tethered rotaxane repeat units are reported. Hydrogen bonding between acidic alcohols and the N-heteroaromatic groups in the rotaxanes attenuates polymer fluorescence. In addition, the rotaxane groups create precise three-dimensional pockets for metal binding, which results ... |
15248778 | Supramolecular photosystem II organization in grana thylakoid membranes: evidence for a structured arrangement. | The distribution of photosystem (PS) II complexes in stacked grana thylakoids derived from electron microscopic images of freeze-fractured chloroplasts are examined for the first time using mathematical methods. These characterize the particle distribution in terms of a nearest neighbor distribution function and a pair... |
15247336 | Binding of phage Phi29 architectural protein p6 to the viral genome: evidence for topological restriction of the phage linear DNA. | Bacillus subtilis phage Phi29 protein p6 is required for DNA replication and promotes the switch from early to late transcription. In vivo it binds all along the viral linear DNA, which suggests a global role as an architectural protein; in contrast, binding to bacterial DNA is negligible. This specificity could be due... |
15240708 | TLR9 is localized in the endoplasmic reticulum prior to stimulation. | In mammals, 10 TLRs recognize conserved pathogen-associated molecular patterns, resulting in the induction of inflammatory innate immune responses. One of these, TLR9, is activated intracellularly by bacterial DNA and synthetic oligodeoxynucleotides (ODN), containing unmethylated CpG dinucleotides. Following treatment ... |
15241554 | Enhanced heparan sulfate proteoglycan-mediated uptake of cell-penetrating peptide-modified liposomes. | Protein transduction domains (PTDs) are used to enhance cellular uptake of drugs, proteins, polynucleotides or liposomes. In this study, functionalized Antennapedia (Antp, aa 43-58) and HIV Tat (aa 47-57) peptides were coupled to small unilamellar liposomes via thiol-maleimide linkage. Modified liposomes showed higher ... |
15240128 | Overexpression of caveolin-1 increases plasma membrane fluidity and reduces P-glycoprotein function in Hs578T/Dox. | Cholesterol is a key lipid in mediating the enzyme activity or signaling pathway of many proteins on the plasma membrane in mammalian cells. In this report, we demonstrate for the first time that after overexpressing caveolin-1, the plasma membrane cholesterol level was decreased by about 12% and 30% for doxorubicin-se... |
15238012 | Two-dimensional supramolecular organization of copper octaethylporphyrin and cobalt phthalocyanine on Au(111): molecular assembly control at an electrochemical interface. | Mixed adlayers of 2,3,7,8,12,13,17,18-octaethyl-21H,23H-porphine copper(II) (CuOEP) and cobalt(II) phthalocyanine (CoPc) were prepared by immersing Au(111) substrate in a benzene solution containing CuOEP and CoPc molecules, and they were investigated in 0.1 M HClO(4) by cyclic voltammetry (CV) and in-situ scanning tun... |
15237983 | AFM-induced amine deprotection: triggering localized bond cleavage by application of tip/substrate voltage bias for the surface self-assembly of nanosized dendritic objects. | An alpha,alpha-dimethyl-3,5-dimethoxybenzyloxycarbonyl (DDZ)-protected amine monolayer can be selectively deprotected by the application of a voltage bias from a conducting AFM tip to afford localized nanoscale patterns that can be visualized by self-assembly of dendritic molecular objects with terminal carboxylic acid... |
15237975 | Strong blue photoluminescence and ECL from OH-terminated PAMAM dendrimers in the absence of gold nanoparticles. | A product showing strong blue photoluminescence was obtained by oxidation of OH-terminated PAMAM dendrimers, such as G4-OH, G2-OH, and G0-OH, with HAuCl4 or (NH4)2S2O8. The fluorescence emission spectrum peaked at 450 nm, while the excitation maximum was at 380 nm, independent of the generation of dendrimer. The produc... |
15238264 | Membrane order conservation in raft and non-raft regions of hepatocyte plasma membranes from thermally acclimated rainbow trout. | Homeoviscous adaptation (HVA), the thermal conservation of membrane fluidity/order at different body temperatures, has been observed to varying degrees in different membranes. However, HVA has not been studied in raft and non-raft regions of the plasma membrane (PM) separately. Rafts are ordered PM microdomains implica... |
15237433 | Helicobacter pylori lipopolysaccharide: biological activities in vitro and in vivo, pathological correlation to human chronic gastritis and peptic ulcer. | <h4>Aim</h4>To determine the biological activity of Helicobacter pylori (H. pylori) lipopolysaccharide (H-LPS) and understand pathological correlation between H-LPS and human chronic gastritis and peptic ulcer.<h4>Methods</h4>H-LPS of a clinical H. pylori strain and LPS of Escherichia coli strain O55:B5 (E-LPS) were ex... |
15236559 | Possible role of relativistic effects in the plasticity of the coordination geometry of cadmium(II). A voltammetric study of the stability of the complexes of cadmium(II) with 12-crown-4,15-crown-5 and 18-crown-6 in aqueous solution and the structures of [Cd(benzo-18-crown-6)(NCS)(2)] and [K(18-crown-6)][Cd(SCN)(3)]. | A differential pulse voltammetric study of complexes of Cd(II) and Pb(II) with crown ethers is reported. Measured log K(1) values for Cd(II) with 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane), 15-crown-5 (1,4,7,10,13-pentaoxacyclopentadecane), and 12-crown-4 (1,4,7,10-tetraoxacyclododecane) are respectively 2.53 (... |
15236552 | Silver coordination chemistry of a new versatile "Janus"-type N(2),O(2)-bichelating donor, formation of an unprecedented supramolecular network of binuclear silver building blocks containing a five-coordinate beta-diketonate, and isolation of unexpected silver-tin-silver heterotrimetallic complexes from silver metathes... | Synthetic, spectroscopic, and single-crystal X-ray studies are reported for several complexes of silver(I) with the N(2),O(2)-bichelating Q(py) ligand (HQ(py) = 1-(2-pyridyl)-3-methyl-4-trifluoroacetylpyrazol-5-one). Direct interaction between HQ(py) and AgNO(3) in methanol, in the presence of NaOCH(3), affords derivat... |
15236550 | Six-membered metalla-coronands. synthesis and crystal packing: columns, compartments, and 3D-networks. | Reaction of various N-substituted diethanolamines H(2)L(3) (4) with calcium hydride and iron(III) chloride leads to the self-assembly of six-membered ferric wheels [Fe(6)X(6)(L(3))(6)] (5). Principally, all the iron coronands are isostructural; however, they differ fundamentally with respect to their crystal packing. E... |
15236549 | Spectroscopic and structural study of metal-metal bonded metalloporphyrinic derivatives: the case of rhodium-indium. | The synthesis and spectroscopic characterization of heterometallic porphyrinate derivatives containing rhodium-indium metal-metal bonds are reported. The investigated compounds are represented by the formula [(Porph)RhIn(Porph')], where Porph and Porph' are OEP, TPP, beta-Cl(4)TPP, beta-Cl(8)TPP, or TPyP. UV-Visible sp... |
15236543 | Influence of the [2.1.1]-(2,6)-pyridinophane macrocycle ring size constraint on the structure and reactivity of copper complexes. | The macrocycle [2.1.1]-(2,6)-pyridinophane (L) binds to CuCl to give a monomeric molecule with tridentate binding of the ligand but in a distorted tetrahedral "3 + 1" geometry, where one nitrogen forms a longer (by 0.12 A) bond to Cu. In dichloromethane solvent this pyridine donor undergoes facile site exchange with a ... |
15236540 | Lead and thallium tetrakis(imidazolyl)borates: modifying structure by varying metal and anion. | We are using the coordinating anions tetrakis(imidazolyl)borate and tetrakis(4-methylimidazolyl)borate to construct new metal-organic framework structures. In this report, we are exploring materials similar in composition to the previously reported layered network structure Pb[B(Im)(4)](NO(3))(nH(2)O). The metal in thi... |
15236527 | Supramolecular spin-crossover iron complexes based on imidazole-imidazolate hydrogen bonds. | The [Fe(II)(H(3)L)](BF(4))(2).3H(2)O (1) complex was synthesized, where H(3)L (tris[[2-[(imidazole-4-yl)methylidene]amino]ethyl]amine) is a tripodal ligand obtained by condensation of tris(2-aminoethyl)amine and 4-formylimidazole (fim) in a 1:3 molar ratio. Starting from 1, a series of complexes, [Fe(II)(H(1.5)L)](BF(4... |
15235229 | [Polyfection as nonviral gene transfer method -design of novel nonviral vector using alpha-cyclodextrin]. | Due to the growing concerns over the toxicity and immunogenicity of viral DNA delivery systems, DNA delivery via nonviral routes has become more desirable and advantageous. In particular, polycation complexes with DNA (polyplex) are attractive nonviral vectors. To design novel polycationic vectors, we prepared polyamid... |
15233796 | Factor XII binding to endothelial cells depends on caveolae. | It is now generally accepted that factor XII (FXII) binds to cellular surfaces in the vascular system. One of the suggested receptors of this binding is the glycosylphosphatidylinositol-anchored urokinase-like plasminogen activator (u-PAR) harbored in caveolae/lipid rafts. However, binding of FXII to human umbilical ve... |
15230601 | Preparation and conformation of dioxocalix[4]arene derivatives. | CrO(3) oxidation experiments conducted on atropisomeric forms of 2 (2(paco), 2(1,3)(-)(alt), and 2(1,2)(-)(alt)) indicate that under the reaction conditions only methylene groups located between pairs of geminal rings oriented in an anti disposition are oxidized to carbonyls. NMR data suggest that the tetrahydroxydioxo... |
15230577 | One-step synthesis and characterization of difunctionalized N-confused tetraphenylporphyrins. | Three disubstituted N-confused porphyrins (2-4) were prepared in ca. 4% yield using a one-pot synthesis. These porphyrins bear 3,5-di-tert-butylphenyl groups substituted at the C(5) and C(20) meso positions and para-substituted (Br, NO(2), ethynyl) phenyl groups at the C(10) and C(15) meso positions. The specific orien... |
15232619 | Caspase-cleavage of tau is an early event in Alzheimer disease tangle pathology. | Neurofibrillary tangles (NFTs) are composed of abnormal aggregates of the cytoskeletal protein tau. Together with amyloid beta (Abeta) plaques and neuronal and synaptic loss, NFTs constitute the primary pathological hallmarks of Alzheimer disease (AD). Recent evidence also suggests that caspases are activated early in ... |
15231733 | U2AF homology motifs: protein recognition in the RRM world. | Recent structures of the heterodimeric splicing factor U2 snRNP auxiliary factor (U2AF) have revealed two unexpected examples of RNA recognition motif (RRM)-like domains with specialized features for protein recognition. These unusual RRMs, called U2AF homology motifs (UHMs), represent a novel class of protein recognit... |
15226428 | Six1 and Eya1 expression can reprogram adult muscle from the slow-twitch phenotype into the fast-twitch phenotype. | Muscle fibers show great differences in their contractile and metabolic properties. This diversity enables skeletal muscles to fulfill and adapt to different tasks. In this report, we show that the Six/Eya pathway is implicated in the establishment and maintenance of the fast-twitch skeletal muscle phenotype. We demons... |
15225077 | Supramolecular polymerization and gel formation of bis(merocyanine) dyes driven by dipolar aggregation. | Two highly dipolar merocyanine dyes were tethered by a rigid tris(n-dodecyloxy)xylylene unit that preorganizes the dyes for a supramolecular polymerization process through intermolecular aggregation of the dyes. UV/vis spectroscopy revealed a solvent dependent equilibrium between monomeric dyes and two different types ... |
15225071 | Self-assembly of supramolecular light-harvesting arrays from covalent multi-chromophore perylene-3,4:9,10-bis(dicarboximide) building blocks. | We report on two multi-chromophore building blocks that self-assemble in solution and on surfaces into supramolecular light-harvesting arrays. Each building block is based on perylene-3,4:9,10-bis(dicarboximide) (PDI) chromophores. In one building block, N-phenyl PDI chromophores are attached at their para positions to... |
15225026 | Supramolecular reactor from self-assembly of rod-coil molecule in aqueous environment. | We synthesized an amphiphilic coil-rod-coil triblock molecule consisting of hexa-p-phenylene as a rod block and poly(ethylene oxide) with the number of repeating units of 17 as coil blocks and investigated aggregation behavior in aqueous environment. The rod-coil molecule was observed to aggregate into discrete micelle... |
15224191 | Agonist-induced trafficking of the low-affinity formyl peptide receptor FPRL1. | The formyl peptide-like receptor FPRL1 is a member of the chemoattractant subfamily of G protein- coupled receptors involved in regulating leukocyte migration in inflammation. To elucidate mechanisms underlying the internalization of ligand-bound FPRL1 and possible receptor recycling, we characterized the endocytic iti... |
15224189 | Accumulation of oxidized lipid-protein complexes alters phagosome maturation in retinal pigment epithelium. | Lipid peroxidation has been implicated in many age-associated disorders including macular degeneration of the retina. We sought to elucidate the mechanism by which accumulation of oxidized LDL (oxLDL) reduces the ability of retinal pigment epithelium (RPE) to process photoreceptor outer segments (OS) as a model of pero... |
15224188 | Hemokinins and endokinins. | The mammalian tachykinins are a family of peptides that, until recently, has included substance P (SP), neurokinin A and neurokinin B. Since, the discovery of a third preprotachykinin gene ( TAC4), the number of tachykinins has more than doubled to reveal several species-divergent peptides. This group includes hemokini... |
15219875 | Collagens and collagen-related matrix components in the human and mouse eye. | The three-dimensional structure of the eye plays an important role in providing a correct optical environment for vision. Much of this function is dependent on the unique structural features of ocular connective tissue, especially of the collagen types and their supramolecular structures. For example, the organization ... |
15220444 | Interaction of DNA with the movement proteins of geminiviruses revisited. | Geminiviruses manage the transport of their DNA within plants with the help of three proteins, the coat protein (CP), the nuclear shuttle protein (NSP), and the movement protein (MP). The DNA-binding capabilities of CP, NSP, and MP of Abutilon mosaic virus (AbMV; family Geminiviridae; genus Begomovirus) were scrutinize... |
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