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11121067 | A whole-genome microarray reveals genetic diversity among Helicobacter pylori strains. | Helicobacter pylori colonizes the stomach of half of the world's population, causing a wide spectrum of disease ranging from asymptomatic gastritis to ulcers to gastric cancer. Although the basis for these diverse clinical outcomes is not understood, more severe disease is associated with strains harboring a pathogenic... |
11121060 | Changing T cell specificity by retroviral T cell receptor display. | The diversity of the T cell receptor (TCR) repertoire is limited, because of the processes of positive and negative T cell selection. To obtain T cells with specificities beyond the immune system's capacity, we have developed a strategy for retroviral TCR display. In this approach, a library of T cell variants is gener... |
11087814 | Toward detecting and identifying macromolecules in a cellular context: template matching applied to electron tomograms. | Electron tomography is the only technique available that allows us to visualize the three-dimensional structure of unfixed and unstained cells currently with a resolution of 6-8 nm, but with the prospect to reach 2-4 nm. This raises the possibility of detecting and identifying specific macromolecular complexes within t... |
11106386 | Species-specific polyamines from diatoms control silica morphology. | Biomineralizing organisms use organic molecules to generate species-specific mineral patterns. Here, we describe the chemical structure of long-chain polyamines (up to 20 repeated units), which represent the main organic constituent of diatom biosilica. These substances are the longest polyamine chains found in nature ... |
11106379 | Femtosecond studies of protein-ligand hydrophobic binding and dynamics: human serum albumin. | In this contribution, we report studies of the nature of the dynamics and hydrophobic binding in protein-ligand complexes of human serum albumin with 2-(2'-hydroxyphenyl)-4-methyloxazole. With femtosecond time resolution, we examined the orientational motion of the ligand, its intrinsic nuclear motions, and the lifetim... |
11106376 | Femtosecond direct observation of charge transfer between bases in DNA. | Charge transfer in supramolecular assemblies of DNA is unique because of the notion that the pi-stacked bases within the duplex may mediate the transport, possibly leading to damage and/or repair. The phenomenon of transport through pi-stacked arrays over a long distance has an analogy to conduction in molecular electr... |
11118374 | Role of M protein aggregation in defective assembly of temperature-sensitive M protein mutants of vesicular stomatitis virus. | The goal of these experiments was to determine the steps in virus assembly that are defective at the nonpermissive temperature in temperature-sensitive (ts) matrix (M) protein mutants of vesicular stomatitis virus. It has been proposed that mutations in M protein either reduce the binding affinity for nucleocapsids or ... |
11118214 | P/CAF-mediated acetylation regulates the function of the basic helix-loop-helix transcription factor TAL1/SCL. | The basic helix-loop-helix transcription factor TAL1 (or SCL) is a critical regulator of hematopoietic and vascular development and is misexpressed in the majority of patients with T-cell acute lymphoblastic leukemia. We found previously that TAL1 could interact with transcriptional co-activator and co-repressor comple... |
11118208 | Membrane association induces a conformational change in the Ebola virus matrix protein. | The matrix protein VP40 from Ebola virus is targeted to the plasma membrane, where it is thought to induce assembly and budding of virions through its association with the lipid bilayer. Ebola virus VP40 is expressed as a monomeric molecule in solution, consisting of two loosely associated domains. Here we show that a ... |
11113453 | Cycloamylose as an efficient artificial chaperone for protein refolding. | High molecular weight cyclic alpha-1,4-glucan (referred to as cycloamylose) exhibited an artificial chaperone property toward three enzymes in different categories. The inclusion properties of cycloamylose effectively accommodated detergents, which keep the chemically denatured enzymes from aggregation, and promoted pr... |
11113450 | Tc1, from Tityus cambridgei, is the first member of a new subfamily of scorpion toxin that blocks K(+)-channels. | A new peptide, Tc1, containing only 23 amino acids closely packed by three disulfide bridges was isolated from the Amazonian scorpion Tityus cambridgei. It blocks reversibly the Shaker B K(+)-channels with a K(d) of 65 nM and displaces binding of noxiustoxin to mouse brain synaptosome membranes. It is the shortest know... |
11113554 | Expression, purification and characterization of beta domain and beta domain dimer of metallothionein. | In order to examine the independent self-assembly of the beta fragment of metallothionein and the interaction between two domains with the linker sequence, Lys-Lys-Ser, the chemically synthesized genes of the beta domain and its dimer (beta-KKS-beta) were cloned into vector pGEX-4T-1 and expressed as carboxyl terminal ... |
11112598 | Synthesis of persialylated beta-cyclodextrins. | The synthesis of homogeneous hepta-antennated C-6 branched sialosyl cyclomaltoheptose derivatives (persialylated beta-cyclodextrins) has been performed in good to excellent yields, and the compounds have been fully characterized. The thioacetate N-acetylneuraminic acid derivative 6 was selectively de-S-acetylated and c... |
11112593 | Competitive formation of helical cycloocta- and cyclododecapyrroles. | In connection with a study aimed at the evaluation of electronic effects in spiro-dicorrole (1a) and its binuclear Ni(II) complex (1b) we became interested in gem-dimethyl-substituted cyclotetrapyrrole (2a) and the corresponding Ni(II) complex (2b). Attempts to prepare 2a as the 12,13,16,17-tetraethyl-2,3,7, 8-tetramet... |
11112570 | Molecular modeling (MM2 and PM3) and experimental (NMR and thermal analysis) studies on the inclusion complex of salbutamol and beta-cyclodextrin. | The inclusion complex of salbutamol and beta-cyclodextrin (beta-CD) is studied by computational (MM2 and PM3) and experimental techniques. Molecular modeling calculations predict two different orientations of salbutamol in the beta-CD cavity in vacuo and in aqueous solution. In vacuo calculations show that the introduc... |
11111078 | Sterol methyl transferase: enzymology and inhibition. | Sterol C-methylations catalyzed by the (S)-adenosyl-L-methionine: Delta(24)-sterol methyl transferase (SMT) have provided the focus for study of electrophilic alkylations, a reaction type of functional importance in C-C bond formation of natural products. SMTs occur generally in nature, but do not occur in animal syste... |
11108967 | Metastasis-associated protein Mts1 (S100A4) inhibits CK2-mediated phosphorylation and self-assembly of the heavy chain of nonmuscle myosin. | A role for EF-hand calcium-binding protein Mts1 (S100A4) in the phosphorylation and the assembly of myosin filaments was studied. The nonmuscle myosin molecules form bipolar filaments, which interact with actin filaments to produce a contractile force. Phosphorylation of the myosin plays a regulatory role in the myosin... |
11106635 | First-principles determination of hybrid bilayer membrane structure by phase-sensitive neutron reflectometry. | The application of a new, phase-sensitive neutron reflectometry method to reveal the compositional depth profiles of biomimetic membranes is reported. Determination of the complex reflection amplitude allows the related scattering length density (SLD) profile to be obtained by a first-principles inversion without the n... |
11106631 | Ultrastructural organization of amyloid fibrils by atomic force microscopy. | Atomic force microscopy has been employed to investigate the structural organization of amyloid fibrils produced in vitro from three very different polypeptide sequences. The systems investigated are a 10-residue peptide derived from the sequence of transthyretin, the 90-residue SH3 domain of bovine phosphatidylinosito... |
11106630 | Biomolecular interactions measured by atomic force microscopy. | Atomic force microscopy (AFM) is nowadays frequently applied to determine interaction forces between biological molecules. Starting with the detection of the first discrete unbinding forces between ligands and receptors by AFM only several years ago, measurements have become more and more quantitative. At the same time... |
11106622 | Area per lipid and acyl length distributions in fluid phosphatidylcholines determined by (2)H NMR spectroscopy. | Deuterium ((2)H) NMR spectroscopy provides detailed information regarding the structural fluctuations of lipid bilayers, including both the equilibrium properties and dynamics. Experimental (2)H NMR measurements for the homologous series of 1, 2-diacyl-sn-glycero-3-phosphocholines with perdeuterated saturated chains (f... |
11106619 | Design of supported membranes tethered via metal-affinity ligand-receptor pairs. | Model lipid layers are very promising in investigating the complex network of recognition, transport and signaling processes at membranes. We have developed a novel and generic approach to create supported lipid membranes tethered by metal-affinity binding. By self-assembly we have generated various interfaces that dis... |
11106603 | Kinetics of association of anti-lysozyme monoclonal antibody D44.1 and hen-egg lysozyme. | Association rate constants for antigen/antibody associations have been computed by Brownian Dynamics simulations of D. L. Ermak and J. A. McCammon, J. Chem. Phys. 69:1352-1360, 1978. The model of monoclonal antibody (mAb) D44.1 is based on crystallographic data (B. C. Braden et al., J. Mol. Biol. 243:767-781, 1994). El... |
11104817 | Positive and negative aspects of the human immunodeficiency virus protease: development of inhibitors versus its role in AIDS pathogenesis. | In this review we summarize multiple aspects of the human immunodeficiency virus (HIV) protease from both structural and functional viewpoints. After an introductory overview, we provide an up-to-date status report on protease inhibitors (PI). This proceeds from a discussion of PI structural design, to how PI are optim... |
11095718 | Drug-resistant Drosophila indicate glutamate-gated chloride channels are targets for the antiparasitics nodulisporic acid and ivermectin. | The fruit fly Drosophila melanogaster was used to examine the mode of action of the novel insecticide and acaricide nodulisporic acid. Flies resistant to nodulisporic acid were selected by stepwise increasing the dose of drug in the culture media. The resistant strain, glc(1), is at least 20-fold resistant to nodulispo... |
11095707 | Crystal structures of photosynthetic reaction center and high-potential iron-sulfur protein from Thermochromatium tepidum: thermostability and electron transfer. | The reaction center (RC) of photosynthetic bacteria is a membrane protein complex that promotes a light-induced charge separation during the primary process of photosynthesis. In the photosynthetic electron transfer chain, the soluble electron carrier proteins transport electrons to the RC and reduce the photo-oxidized... |
11087831 | Microfluidic tectonics: a comprehensive construction platform for microfluidic systems. | A microfluidic platform for the construction of microscale components and autonomous systems is presented. The platform combines liquid-phase photopolymerization, lithography, and laminar flow to allow the creation of complex and autonomous microfluidic systems. The fabrication of channels, actuators, valves, sensors, ... |
11106427 | Sites of limited proteolysis in the pyruvate decarboxylase component of the pyruvate dehydrogenase multienzyme complex of Bacillus stearothermophilus and their role in catalysis. | The E1 component (pyruvate decarboxylase) of the pyruvate dehydrogenase complex of Bacillus stearothermophilus is a heterotetramer (alpha2beta2) of E1alpha and E1beta polypeptide chains. The domain structure of the E1alpha and E1beta chains, and the protein-protein interactions involved in assembly, have been studied b... |
11104702 | Coexpression of alpha and beta subunits of prolyl 4-hydroxylase stabilizes the triple helix of recombinant human type X collagen. | We have reported previously on the expression of recombinant human type X collagen (hrColX) in HEK 293 and HT 1080 cells by using the eukaryotic expression vector pCMVsis (in which CMV stands for cytomegalovirus). Several stably transfected clones secreted full-length triple-helical hrColX molecules in large amounts, b... |
11104694 | Size of the ligand complex between the N-terminal domain of the gene III coat protein and the non-infectious phage strongly influences the usefulness of in vitro selective infective phage technology. | The selective infective phage (SIP) technology allows a rapid positive selection of interacting pairs of biological molecules that restore to non-infectious phages their ability to infect the bacterial host. After a successful infection, the phage is amplified and the DNA encoding the interacting ligand is isolated fro... |
11104678 | Conversion of Escherichia coli pyruvate oxidase to an 'alpha-ketobutyrate oxidase'. | Escherichia coli pyruvate oxidase (PoxB), a lipid-activated homotetrameric enzyme, is active on both pyruvate and 2-oxobutanoate ('alpha-ketobutyrate'), although pyruvate is the favoured substrate. By localized random mutagenesis of residues chosen on the basis of a modelled active site, we obtained several PoxB enzyme... |
11104674 | Kinetic alteration of a human dihydrodiol/3alpha-hydroxysteroid dehydrogenase isoenzyme, AKR1C4, by replacement of histidine-216 with tyrosine or phenylalanine. | Human dihydrodiol dehydrogenase with 3alpha-hydroxysteroid dehydrogenase activity exists in four forms (AKR1C1-1C4) that belong to the aldo-keto reductase (AKR) family. Recent crystallographic studies on the other proteins in this family have indicated a role for a tyrosine residue (corresponding to position 216 in the... |
11102864 | Self-assembled nanostructures based on DNA: towards the development of nanobiotechnology. | DNA is a promising construction material for the supramolecular 'bottom-up' engineering of artificial nanostructured devices. The use of DNA for the selective positioning of macromolecular components, the fabrication of nanostructured DNA scaffolds, as well as the DNA-templated synthesis of nanometer-sized and mesoscop... |
11102379 | Evolution of dosage compensation in Diptera: the gene maleless implements dosage compensation in Drosophila (Brachycera suborder) but its homolog in Sciara (Nematocera suborder) appears to play no role in dosage compensation. | In Drosophila melanogaster and in Sciara ocellaris dosage compensation occurs by hypertranscription of the single male X chromosome. This article reports the cloning and characterization in S. ocellaris of the gene homologous to maleless (mle) of D. melanogaster, which implements dosage compensation. The Sciara mle gen... |
11102361 | The Caenorhabditis elegans dosage compensation machinery is recruited to X chromosome DNA attached to an autosome. | The dosage compensation machinery of Caenorhabditis elegans is targeted specifically to the X chromosomes of hermaphrodites (XX) to reduce gene expression by half. Many of the trans-acting factors that direct the dosage compensation machinery to X have been identified, but none of the proposed cis-acting X chromosome-r... |
11102518 | Endosome to Golgi transport of ricin is regulated by cholesterol. | We have here studied the role of cholesterol in transport of ricin from endosomes to the Golgi apparatus. Ricin is endocytosed even when cells are depleted for cholesterol by using methyl-beta-cyclodextrin (m beta CD). However, as here shown, the intracellular transport of ricin from endosomes to the Golgi apparatus, m... |
11101810 | In vitro selection of signaling aptamers. | Reagentless biosensors that can directly transduce molecular recognition to optical signals should potentiate the development of sensor arrays for a wide variety of analytes. Nucleic acid aptamers that bind ligands tightly and specifically can be readily selected, but may prove difficult to adapt to biosensor applicati... |
11101902 | Structural basis of the recognition of the dishevelled DEP domain in the Wnt signaling pathway. | The DEP domain of Dishevelled (Dvl) proteins transduces signals to effector proteins downstream of Dvl in the Wnt pathway. Here we report that DEP-containing mutants inhibit Wnt-induced, but not Dvl-induced, activation of the transcription factor Lef-1. This inhibitory effect is weakened by a K434M mutation. Nuclear ma... |
11101534 | Separate domains in GCN1 for binding protein kinase GCN2 and ribosomes are required for GCN2 activation in amino acid-starved cells. | GCN2 stimulates GCN4 translation in amino acid-starved cells by phosphorylating the alpha-subunit of translation initiation factor 2. GCN2 function in vivo requires the GCN1/GCN20 complex, which binds to the N-terminal domain of GCN2. A C-terminal segment of GCN1 (residues 2052-2428) was found to be necessary and suffi... |
11099969 | Supramolecular structure of 1H-pyrazoles in the solid state: a crystallographic and ab initio study. | The secondary structure of 1H-unsubstituted pyrazole derivatives bearing only one hydrogen donor group and one or more acceptor groups has been analyzed in terms of some descriptors representing the substituents at C3 and C5. The substituent at C4 appears to affect mainly the tertiary or quaternary structure of these c... |
11101297 | Heme redox potential control in de novo designed four-alpha-helix bundle proteins. | The effects of various mechanisms of metalloporphyrin reduction potential modulation were investigated experimentally using a robust, well-characterized heme protein maquette, synthetic protein scaffold H10A24 [¿CH(3)()CONH-CGGGELWKL.HEELLKK.FEELLKL.AEERLKK. L-CONH(2)()¿(2)](2). Removal of the iron porphyrin macrocycle... |
11095681 | Fission yeast retrotransposon Tf1 integration is targeted to 5' ends of open reading frames. | Target site selection of transposable elements is usually not random but involves some specificity for a DNA sequence or a DNA binding host factor. We have investigated the target site selection of the long terminal repeat-containing retrotransposon Tf1 from the fission yeast Schizosaccharomyces pombe. By monitoring in... |
11095667 | Intact MutY and its catalytic domain differentially contact with A/8-oxoG-containing DNA. | Escherichia coli MutY is an adenine and a weak guanine DNA glycosylase active on DNA substrates containing A/G, A/8-oxoG, A/C or G/8-oxoG mismatches. A truncated form of MutY (M25, residues 1-226) retains catalytic activity; however, the C-terminal domain of MutY is required for specific binding to the 8-oxoG and is cr... |
11094063 | Functional consequences of a polymorphism affecting NF-kappaB p50-p50 binding to the TNF promoter region. | Stimulation of the NF-kappaB pathway often causes p65-p50 and p50-p50 dimers to be simultaneously present in the cell nucleus. A natural polymorphism at nucleotide -863 in the human TNF promoter (encoding tumor necrosis factor [TNF]) region provides an opportunity to dissect the functional interaction of p65-p50 and p5... |
10969072 | Surface-accessible residues in the monomeric and assembled forms of a bacterial surface layer protein. | The S-layer protein SbsB of the thermophilic, Gram-positive organism Bacillus stearothermophilus PV72/p2 forms a crystalline, porous array constituting the outermost component of the cell envelope. SbsB has a molecular mass of 98 kDa, and the corresponding S-layer exhibits an oblique lattice symmetry. To investigate th... |
10982788 | PC12 cells have caveolae that contain TrkA. Caveolae-disrupting drugs inhibit nerve growth factor-induced, but not epidermal growth factor-induced, MAPK phosphorylation. | Nerve growth factor (NGF) induces survival and differentiation of the neural crest-derived PC12 cell line. Caveolae are cholesterol-enriched, caveolin-containing plasma membrane microdomains involved in vesicular transport and signal transduction. Here we demonstrate the presence of caveolae in PC12 cells and their inv... |
10964911 | The forgotten serine. A critical role for Ser-2035.42 in ligand binding to and activation of the beta 2-adrenergic receptor. | Previous work in the beta(2)-adrenergic receptor demonstrated critical interactions between Ser-204 and Ser-207 in the fifth membrane-spanning segment and the meta-OH and para-OH, respectively, of catecholamine agonists (Strader, C. D., Candelore, M. R., Hill, W. S., Sigal, I. S., and Dixon, R. A. (1989) J. Biol. Chem.... |
11092852 | Pleiotropic effect of protein P6 on the viral cycle of bacteriophage phi29. | The product of bacteriophage phi29 early gene 6, protein p6, is a double-stranded-DNA binding protein and one of the more abundant proteins during viral infection. We have studied the role of protein p6 in vivo through the infection of suppressor and nonsuppressor Bacillus subtilis strains with a phage carrying a nonse... |
11090199 | Apelin, the natural ligand of the orphan seven-transmembrane receptor APJ, inhibits human immunodeficiency virus type 1 entry. | In addition to the CCR5 and CXCR4 chemokine receptors, a subset of primary human immunodeficiency virus type 1 (HIV-1) isolates can also use the seven-transmembrane-domain receptor APJ as a coreceptor. A previously identified ligand of APJ, apelin, specifically inhibited the entry of primary T-tropic and dualtropic HIV... |
11090193 | Affinity-tagged miniprion derivatives spontaneously adopt protease-resistant conformations. | An abridged PrP molecule of 106 amino acids designated PrP106 can form infectious miniprions in transgenic (Tg) mice (29). Addition of six-histidine (His(6)) affinity tags to selective sites within PrP106 resulted unexpectedly in new PrP proteins that spontaneously adopted protease-resistant conformations when expresse... |
11090188 | Complex formation by human cytomegalovirus glycoproteins M (gpUL100) and N (gpUL73). | The envelope glycoproteins of human cytomegalovirus (HCMV) virions are incompletely characterized. We have analyzed complex formation between glycoprotein M (gM or gpUL100) and a second glycoprotein. gM-homologous proteins are conserved throughout the herpesvirus family and represent type III membrane proteins containi... |
11090151 | Influenza virus matrix protein is the major driving force in virus budding. | To get insights into the role played by each of the influenza A virus polypeptides in morphogenesis and virus particle assembly, the generation of virus-like particles (VLPs) has been examined in COS-1 cell cultures expressing, from recombinant plasmids, different combinations of the viral structural proteins. The pres... |
11090139 | Mutations in herpes simplex virus glycoprotein D distinguish entry of free virus from cell-cell spread. | Herpes simplex virus type 1 (HSV-1) glycoprotein D (gD) is an essential component of the entry apparatus that is responsible for viral penetration and subsequent cell-cell spread. To test the hypothesis that gD may serve distinguishable functions in entry of free virus and cell-cell spread, mutants were selected for gr... |
11090115 | Effects of diclofenac, aceclofenac and meloxicam on the metabolism of proteoglycans and hyaluronan in osteoarthritic human cartilage. | 1. Since nonsteroidal anti-inflammatory drugs (NSAIDs) may impair the ability of the chondrocyte to repair its damaged extracellular matrix, we explored the changes in the metabolism of newly synthesized proteoglycan and hyaluronan (HA) molecules produced by aceclofenac, diclofenac and meloxicam in human osteoarthritic... |
11085933 | A single amino acid substitution (N297A) in the conserved NPXXY sequence of the human N-formyl peptide receptor results in inhibition of desensitization and endocytosis, and a dose-dependent shift in p42/44 mitogen-activated protein kinase activation and chemotaxis. | The formyl peptide receptor (FPR) is a G-protein-coupled receptor (GPCR) that mediates chemotaxis and stimulates the mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinase pathway. We have examined the functional effects of substitutions of a conserved aspartic acid residue in the second transmem... |
11085917 | Probing the NADPH-binding site of Escherichia coli flavodoxin oxidoreductase. | The structure of the Escherichia coli flavodoxin NADP(+) oxidoreductase (FLDR) places three arginines (R144, R174 and R184) in the proposed NADPH-binding site. Mutant enzymes produced by site-directed mutagenesis, in which each arginine was replaced by neutral alanine, were characterized. All mutants exhibited decrease... |
11084632 | The origin of cellular life. | This essay presents a scenario of the origin of life that is based on analysis of biological architecture and mechanical design at the microstructural level. My thesis is that the same architectural and energetic constraints that shape cells today also guided the evolution of the first cells and that the molecular scaf... |
11083799 | Identification and immunogenicity of group A Streptococcus culture supernatant proteins. | Extracellular proteins made by group A Streptococcus (GAS) play critical roles in the pathogenesis of human infections caused by this bacterium. Although many extracellular GAS proteins have been identified and characterized, there has been no systematic analysis of culture supernatant proteins. Proteins present in the... |
11082203 | X-ray structure of acarbose bound to amylomaltase from Thermus aquaticus. Implications for the synthesis of large cyclic glucans. | As a member of the alpha-amylase superfamily of enzymes, amylomaltase catalyzes either the transglycosylation from one alpha-1,4 glucan to another or an intramolecular cyclization. The latter reaction is typical for cyclodextrin glucanotransferases. In contrast to these enzymes, amylomaltase catalyzes the formation of ... |
11073924 | Degradation of heme in gram-negative bacteria: the product of the hemO gene of Neisseriae is a heme oxygenase. | A full-length heme oxygenase gene from the gram-negative pathogen Neisseria meningitidis was cloned and expressed in Escherichia coli. Expression of the enzyme yielded soluble catalytically active protein and caused accumulation of biliverdin within the E. coli cells. The purified HemO forms a 1:1 complex with heme and... |
11069993 | The level of CD4 expression limits infection of primary rhesus monkey macrophages by a T-tropic simian immunodeficiency virus and macrophagetropic human immunodeficiency viruses. | The entry of primate immunodeficiency viruses into cells is dependent on the interaction of the viral envelope glycoproteins with receptors, CD4, and specific members of the chemokine receptor family. Although in many cases the tropism of these viruses is explained by the qualitative pattern of coreceptor expression, s... |
11033567 | Micelles of poly(ethylene oxide)-block-poly(N-alkyl stearate L-aspartamide): synthetic analogues of lipoproteins for drug delivery. | Stearic acid esters of poly(ethylene oxide)-block-poly(hydroxyethyl L-aspartamide) and poly(ethylene oxide)-block-poly(hydroxyhexyl L-aspartamide) have been synthesized from poly(ethylene oxide)-block-poly(beta-benzyl L-aspartate) by polymer-analogous reactions and self-assembled into a micelle. Transmission electron m... |
11092895 | Zinc release from the CH2C6 zinc finger domain of FILAMENTOUS FLOWER protein from Arabidopsis thaliana induces self-assembly. | The FILAMENTOUS FLOWER gene from Arabidopsis thaliana is a member of a gene family whose role is to specify abaxial cell fate in lateral organs. Analysis of the amino-terminal region of the FILAMENTOUS FLOWER protein suggests that seven cysteine residues at positions 14, 26, 30, 33, 54, 56, and 57, and two histidine re... |
11087758 | FPRP, a major, highly stoichiometric, highly specific CD81- and CD9-associated protein. | CD81 and CD9, members of the transmembrane-4 superfamily (TM4SF; tetraspanins), form extensive complexes with other TM4SF proteins, integrins, and other proteins, especially in mild detergents. In moderately stringent Brij 96 lysis conditions, CD81 and CD9 complexes are virtually identical to each other, but clearly di... |
11084027 | Purification and characterization of a novel calcium-binding protein from the extrapallial fluid of the mollusc, Mytilus edulis. | In the bivalve mollusc Mytilus edulis shell thickening occurs from the extrapallial (EP) fluid wherein secreted shell matrix macromolecules are thought to self-assemble into a framework that regulates the growth of CaCO(3) crystals, which eventually constitute approximately 95% of the mature shell. Herein is the initia... |
11084023 | Evidence for the selective population of FeMo cofactor sites in MoFe protein and its molecular recognition by the Fe protein in transition state complex analogues of nitrogenase. | We have collected synchrotron x-ray solution scattering data for the MoFe protein of Klebsiella pneumoniae nitrogenase and show that the molecular conformation of the protein that contains only one molybdenum per alpha(2)beta(2) tetramer is different from that of the protein that has full occupancy i.e. two molybdenums... |
11069895 | Self-assembly of the vascular endothelial cadherin ectodomain in a Ca2+-dependent hexameric structure. | Vascular endothelial cadherin (VE-cadherin) is a transmembrane protein essential for endothelial cell monolayer integrity (Gulino, D., Delachanal, E., Concord, E., Genoux, Y., Morand, B., Valiron, M. O., Sulpice, E., Scaife, R., Alemany, M., and Vernet, T. (1998) J. Biol. Chem. 273, 29786-29793). This molecule belongs ... |
27134333 | Inhibition of Ecto-Apyrase and Ecto-ATPase by Pyridoxal Phosphate-Related Compounds. | Studies of nucleotide receptors (P2-receptors) in cells and tissues are complicated by cleavage of phosphate groups from nucleotide agonist ligands by ecto-nucleotidases. Some P2 receptor antagonists may also inhibit ecto-nucleotidases, making these studies even more complex. In order to systematically approach this pr... |
23696307 | Chiral J-aggregates formed by achiral cyanine dyes. | The self-assembly of helical supramolecular structures from chiral building units is a basic principle of biological materials. The mesoscopic structure of a chiral molecular aggregate, which formed spontaneously from a nonchiral J-aggregating cyanine dye in aqueous solution, is presented. In single crystals (as shown ... |
16554909 | Effects of Gas-Phase Basicity on the Proton Transfer between Organic Bases and Trifluoroacetic Acid in the Gas Phase: Energetics of Charge Solvation and Salt Bridges. | The unimolecular dissociation pathways and kinetics of a series of protonated trimer ions consisting of two organic bases and trifluoroacetic acid were investigated using blackbody infrared radiative dissociation. Five bases with gas-phase basicities (GB) ranging from 238.4 to 246.2 kcal/mol were used. Both the dissoci... |
11101427 | Molecular assembly and disassembly: novel photolabile molecular hosts | A new approach to the assembly and photochemical disassembly of molecular hosts is developed. It is based on photoinduced fragmentation in hydroxyalkyl dithianes and utilizes a novel spiro-bis-dithiane as a photolabile molecular tether to link two formylated macromolecular blocks, e.g., formyl calixarenes or formyl dib... |
11101419 | A new method for the synthesis of imidazolidinone- and benzimidazolone-containing | A novel acid-catalyzed double nucleophilic addition of bisthiols to heterocyclic bisacetals gives sulfur-containing macrocycles in good yield. Crossover experiments revealed that the acid-catalyzed N-acyl iminium cyclization for the imidazolidinones is reversible. The sulfur atom in the bridge was extruded photochemica... |
11091452 | Wherefore Art Thou Copper? Structures and Reaction Mechanisms of Organocuprate Clusters in Organic Chemistry. | Organocopper reagents provide the most general synthetic tools in organic chemistry for nucleophilic delivery of hard carbanions to electrophilic carbon centers. A number of structural and mechanistic studies have been reported and have led to a wide variety of mechanistic proposals, some of which might even be contrad... |
11082264 | A Comparative Study of Enzymatically and Photochemically Polymerized Artificial Lignin Supramolecular Structures Using Environmental Scanning Electron Microscopy. | Environmental scanning electron microscopy images of the self-assembled structures of enzymatically (DHP) and photochemically polymerized (PCP) artificial lignin are herein presented. Differences in the structural organization between DHP and PCP polymer at the supramolecular level were reported. Based on topological i... |
11080909 | Crown ether-doped sol-gel materials for strontium(II) separation | Hybrid organic/inorganic sol-gel materials containing an encapsulated crown ether ligand were found to selectively remove 91.4 +/- 1.3% of Sr2+ from a solution containing excess of competing ions such as Ca2+. The crown ether ligand, 1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-bis(malonate) ligand (Na4oddm), with... |
11080894 | A method for the determination of binding constants by electrospray ionization mass spectrometry | A new method for the determination of binding constants using electrospray ionization mass spectrometry is presented. The intensity of a reference complex with a known log K value is monitored before and after addition of a second host or guest. On the basis of the change in intensity of the reference complex and extra... |
11080873 | Enhancement of CsNO3 extraction in 1,2-dichloroethane by tris(2-aminoethyl)amine triamide derivatives via a dual-host strategy | A systematic study of a dual-host system exhibiting pairwise anion/cation separations has been performed for CsNO3 extraction. Tripodal triamides 1-4 and 9 derived from condensation of hexanoic (for 1), octanoic (for 2), decanoic (for 3), lauric (for 4), and p-tert-butylbenzoic (for 9) acid with tris(2-aminoethyl)amine... |
11076623 | A simple method for controlling dendritic architecture and diversity: A parallel monomer combination approach | A novel parallel monomer combination approach to manipulating the architectural disposition of dendritic macromolecules is described. It harnesses the synthetic speed and power of the double-stage convergent growth approach and classical parallel synthesis to prepare diverse series of dendrimers that possess a predeter... |
11073667 | Synthesis of new 1,1'-binaphthyl-based chiral phenylenevinylene dendrimers | Dendrimeric meta-substituted phenylenevinylene moieties have been incorporated on a chiral binaphthyl core, providing new chiral and photoluminescent molecules. |
11073647 | Guest-enhanced kinetic stability of hydrogen-bonded dimeric capsules of tetraurea Calix | Inclusion complexes of self-assembled molecular dimers composed of two tetratolylurea calix[4]arenes show strongly different kinetic stability for different guests. In cyclohexane-d(12), half-life times for the exchange of a guest against the solvent vary from 2.9 h (chloroform) through 20 h (benzene) and 74 h (fluorob... |
11073641 | Self-assembly of an amphiphilic | The template-directed synthesis of a [2]rotaxane, in which a pi-electron deficient ring component-cyclobis(paraquat-p-phenylene)-is assembled around a pi-electron rich asymmetric monopyrrolotetrathiafulvalene unit on the rod section of an amphiphilic dumbbell component that is terminated by a hydrophilic dendritic stop... |
11073615 | Supramolecular photochirogenesis. 2. Enantiodifferentiating photoisomerization of cyclooctene included and sensitized by 6-O-modified cyclodextrins | Supramolecular enantiodifferentiating photoisomerization of (Z)-cyclooctene (1Z) to the chiral (E)-isomer (1E) via inclusion and sensitization by modified alpha-, beta-, and/or gamma-cyclodextrin derivatives, possessing benzoate (2a, 3a, 4a), isomeric phthalates (3b-d), and tethered benzamide (3e) chromophores, has bee... |
11073614 | Intramolecular fluorine migration via four-member cyclic transition states | Gaseous CF(3)(+) interchanges F(+) for O with simple carbonyl compounds. CF(3)(+) reacts with propionaldehyde in the gas phase to produce (CH(3))(2)CF(+) via two competing pathways. Starting with 1-(13)C-propionaldehyde, the major pathway (80%) produces (CH(3))(2)CF(+) with the carbon label in one of the methyl groups.... |
11073613 | Efficient synthesis of N-aryl-aza-crown ethers via palladium-catalyzed amination | N-Aryl-aza-crown ethers were efficiently prepared by reaction of an aza-crown ether with an aryl bromide via a palladium-catalyzed amination. The combination of Pd(2)(dba)(3) and a biphenyl-based electron-rich bulky monophosphine is effective for catalyzing the coupling of 1-aza-15-crown-5 with both electron-deficient ... |
11073570 | Giant cyclophanes built from polyphenyl aromatic substructures | Two very large cyclophanes (3, C(132)H(92)O(8)S(4); 4, C(172)H(120)O(8)S(4)) were prepared by means of short syntheses ( approximately 5 steps) from commercial starting materials. In each of these cyclophanes, two octaphenylnaphthalene subunits or two 1, 3-bis(pentaphenylphenyl)benzene subunits were tethered to form th... |
11064054 | Hydrocarbon degradation by a soil microbial population with beta-cyclodextrin as surfactant to enhance bioavailability. | In general the biodegradation of nonchlorinated aliphatic and aromatic hydrocarbons is influenced by their bioavailability. Hydrocarbons are very poorly soluble in water. They are easily adsorbed to clay or humus fractions in the soil, and pass very slowly to the aqueous phase, where they are metabolised by microorgani... |
11064053 | Addition of polar organic solvents can improve the product selectivity of cyclodextrin glycosyltransferase. Solvent effects on cgtase. | Cyclodextrin glycosyltransferase (EC 2.4.1.19, CGTase) is an enzyme that produces cyclodextrins from starch via an intramolecular transglycosylation reaction. Addition of small amounts (10% v/v) of polar organic solvents can affect both the overall production yield and the type of cyclodextrin produced from a maltodext... |
11112983 | Imaging of dynamic changes of the actin cytoskeleton in microextensions of live NIH3T3 cells with a GFP fusion of the F-actin binding domain of moesin. | <h4>Background</h4>The cell surface undergoes continuous change during cell movement. This is characterized by transient protrusion and partial or complete retraction of microspikes, filopodia, and lamellipodia. This requires a dynamic actin cytoskeleton, moesin, components of Rho-mediated signal pathways, rearrangemen... |
11101361 | Effect of ring fluorination on the pharmacology of hallucinogenic tryptamines. | A series of fluorinated analogues of the hallucinogenic tryptamines N,N-diethyltryptamine (DET), 4-hydroxy-N,N-dimethyltryptamine (4-OH-DMT, psilocin), and 5-methoxy-DMT was synthesized to investigate possible explanations for the inactivity of 6-fluoro-DET as a hallucinogen and to determine the effects of fluorination... |
11249149 | Effects of methylmercury and inorganic mercury on the growth of nerve fibers in cultured chick dorsal root ganglia. | Inhibition of the growth of nerve fibers by mercurials was quantitatively estimated by measuring the length of fibers in the cultured chick dorsal root ganglion. Morphological changes in nonneuronal cells were also evaluated. The growth rates of nerve fibers were constant for 2 to 6 days after the start of incubation. ... |
11233650 | Photochemistry of supramolecular systems containing C60. | Fullerenes have been used successfully in the covalent assembly of supramolecular systems that mimic some of the electron transfer steps of photosynthetic reaction centers. In these constructs C60 is most often used as the primary electron acceptor; it is linked to cyclic tetrapyrroles or other chromophores which act a... |
11162731 | Supramolecular structure of a new family of circular proteoglycans mediating cell adhesion in sponges. | Aggregationfactors are the molecules responsible for species-specific cell adhesion in sponges. Here, we present the structure of the aggregation factor from the marine sponge Microciona prolifera, which constitutes the first description of a circular proteoglycan. We have analyzed chemically dissociated and enzymatica... |
11271479 | Competitive binding of a Tris run buffer with chiral crown ether in chiral capillary electrophoresis. | In capillary electrophoresis of primary amine racemates using (+)-(18-crown-6)-tetracarboxylic acid (18C6H4) as a chiral selector, chiral recognition emanates from the differences in the complex formation between 18C6H4 and the two protonated amine enantiomers. The presence of buffer constituents such as tris(hydroxyme... |
11271478 | Enantioseparation of dihydropyridine derivatives by means of neutral and negatively charged beta-cyclodextrin derivatives using capillary electrophoresis. | Employing capillary electrophoresis, the racemates of 29 acidic, neutral and basic dihydropyridines (DHPs) were separated by means of neutral and negatively charged cyclodextrins (CDs). Whereas the enantiomers of the acidic DHPs could be resolved with neutral CDs, mostly alpha- and beta-CD, the enantiomers of the neutr... |
11218868 | [Selective isolation of isopsoralen from crude extract of Psoralea corylifolia. L by using inclusion method of host-guest molecules]. | <h4>Aim</h4>To isolate the chemical components from extracted crude of Psoralea corylifolia L.<h4>Methods</h4>Applicate the function of molecular recognition in supramolecular chemistry, use 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol as the host molecule and chemical components in extracted crude of Psoralea corylifoli... |
11210606 | [Evaluation of 26 esophagectomies from the aspects of complications and survival time]. | The authors analyze a group of 26 patients with oesophageal carcinoma operated in the course of five years with regard to postoperative complications and period of survival. In seven instances they used Ivor-Lewis operation, 17 times Orringer's operation, twice a palliative retrosternal bypass. Twenty one times they us... |
11150712 | A CD(4)/T(4) receptor peptide ligand labeled with technetium-99m: synthesis and biological activity. | The octapeptide D-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-NH(2) ([D-Ala(1)]TNH(2)), an analog of peptide T (H-Ala-Ser-Thr-Thr-Thr-Asn-Tyr-Thr-OH) associated with CD(4)/T(4) receptors involved in human immunodeficiency virus infection, was combined with the chelating polyazamacrocycle 1,4,8,11-tetraazacyclotetradecane (cyclam) ... |
11193431 | Binding affinity of the methyl ester of AK-toxin I to membrane fractions from Japanese pear leaves. | The binding site of AK-toxin, a host-specific toxin against Japanese pear, was searched for in the membrane fractions of the pear leaves, using 3H-labeled AK-toxin I methyl ester. Binding activity, which was displaceable by the unlabeled ligand, was observed for microsomal fraction from a toxin-susceptible cultivar, Ni... |
11193419 | Dietary beta- and gamma-cyclodextrins stimulation of hepatic metallothionein gene expression in rats. | This study investigated whether hepatic metallothionein gene expression is affected by dietary cyclodextrins. Young male Wistar rats were fed a basal diet or cyclodextrin-supplemented (50 g of cyclodextrin per kg diet) diets for 7 d. Copper content in the liver did not show any significant changes among rats fed the ba... |
11193409 | Synthesis of novel heterobranched beta-cyclodextrins from alpha-D-mannosylmaltotriose and beta-cyclodextrin by the reverse action of pullulanase, and isolation and characterization of the products. | Alpha-D-mannosyl-maltotriose (Man-G3) were synthesized from methyl alpha-mannoside and maltotriose by the transfer action of alpha-mannosidase. (Man-G3)-betaCD and (Man-G3)2-betaCD were produced in about 20% and 4% yield, respectively when Aerobacter aerogenes pullulanase (160 units per 1 g of Man-G3) was incubated wit... |
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