id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
|---|---|---|
14767925 | Alpha,alpha-disubstituted glycines bearing a large hydrocarbon ring: peptide self-assembly through hydrophobic recognition. | A method was developed for synthesizing alpha,alpha-disubstituted glycine residues bearing a large (more than 15-membered) hydrophobic ring. The ring-closing metathesis reactions of the dialkenylated malonate precursors proceed efficiently, particularly when long methylene chains tether both terminal olefin groups. Sur... |
14767924 | Supramolecular photomagnetic materials: photoinduced dimerization of ferrocene-based polychlorotriphenylmethyl radicals. | New ferrocenyl Schiff-base polychlorotriphenylmethyl radicals have been synthesized and characterized. The imino group of one such radical undergoes an irreversible trans to cis structural isomerization induced by light. Such photoinduced isomerization has been monitored by UV/Vis and ESR spectroscopy and also monitore... |
14767923 | Supramolecular control of charge-transfer dynamics on dye-sensitized nanocrystalline TiO2 films. | A [Ru(dcbpy)(2)(NCS)(2)] dye has been chemically modified by the addition of a secondary electron donor moiety, N,N-(di-p-anisylamino)phenoxymethyl. Optical excitation of the modified dye adsorbed to nanocrystalline TiO(2) films shows a remarkably long-lived charge-separated state, with a decay half time of 0.7 s. Semi... |
14765190 | A route to high surface area, porosity and inclusion of large molecules in crystals. | One of the outstanding challenges in the field of porous materials is the design and synthesis of chemical structures with exceptionally high surface areas. Such materials are of critical importance to many applications involving catalysis, separation and gas storage. The claim for the highest surface area of a disorde... |
14762120 | Activity-dependent expression of acyl-coenzyme a-binding protein in retinal muller glial cells evoked by optokinetic stimulation. | Long-term horizontal optokinetic stimulation (HOKS) decreases the gain of the horizontal optokinetic reflex and evokes the second phase of optokinetic afternystagmus (OKAN-II). We investigated the possible molecular constituents of this adaptation. We used a differential display reverse transcriptase-PCR screen for mRN... |
14761207 | Macrocyclic polyamines deplete cellular ATP levels and inhibit cell growth in human prostate cancer cells. | In solid tumors, when O(2) partial pressure drops below 10 mmHg, ATP levels rapidly decrease due to the Warburg effect. It is known that certain macrocyclic polyamines catalyze the chemical hydrolysis of ATP with release of inorganic phosphate. Since tumor cells have diminished ATP levels as compared to normal cells, w... |
14761181 | Synthesis of a 5-methylindolyl-containing macrocycle that displays ultrapotent Grb2 SH2 domain-binding affinity. | The growth factor receptor-bound protein 2 (Grb2) is an SH2 domain-containing docking module that represents an attractive target for anticancer therapeutic intervention. Here, a ring-closing metathesis approach is utilized to synthesize a 5-methylindolyl-containing tetrapeptide mimetic (6) that exhibits unprecedented ... |
14761991 | Architecture of the Bacteroides cellulosolvens cellulosome: description of a cell surface-anchoring scaffoldin and a family 48 cellulase. | A large gene downstream of the primary Bacteroides cellulosolvens cellulosomal scaffoldin (cipBc, now renamed scaA) was sequenced. The gene, termed scaB, contained an N-terminal leader peptide followed by 10 type I cohesins, an "X" domain of unknown structure and function, and a C-terminal S-layer homology (SLH) surfac... |
14761985 | H-NS represses Salmonella enterica serovar Typhimurium dsbA expression during exponential growth. | Disulfide bond formation catalyzed by disulfide oxidoreductases occurs in the periplasm and plays a major role in the proper folding and integrity of many proteins. In this study, we were interested in elucidating factors that influence the regulation of dsbA, a gene coding for the primary disulfide oxidoreductase foun... |
14653781 | Targeting of calcium/calmodulin-dependent protein kinase II. | Calcium/calmodulin-dependent protein kinase II (CaMKII) has diverse roles in virtually all cell types and it is regulated by a plethora of mechanisms. Local changes in Ca2+ concentration drive calmodulin binding and CaMKII activation. Activity is controlled further by autophosphorylation at multiple sites, which can ge... |
14609430 | Acylation of SC4 dodecapeptide increases bactericidal potency against Gram-positive bacteria, including drug-resistant strains. | We have conjugated dodecyl and octadecyl fatty acids to the N-terminus of SC4, a potently bactericidal, helix-forming peptide 12-mer (KLFKRHLKWKII), and examined the bactericidal activities of the resultant SC4 'peptide-amphiphile' molecules. SC4 peptide-amphiphiles showed up to a 30-fold increase in bactericidal activ... |
14558887 | The heptapeptide LSARLAF mediates platelet activation through phospholipase Cgamma2 independently of glycoprotein IIb-IIIa. | The seven-amino-acid peptide LSARLAF has been reported to activate platelets via the integrin GPIIb-IIIa (glycoprotein IIb-IIIa). Activation by LSARLAF is reinforced by release of ADP and thromboxanes, but the initiating event in the signalling cascade is not known. In the present study, we demonstrate that LSARLAF sti... |
14759218 | Beta-cyclodextrin host-guest complexes probed under thermodynamic equilibrium: thermodynamics and AFM force spectroscopy. | The rupture forces of individual host-guest complexes between beta-cyclodextrin (beta-CD) heptathioether monolayers on Au(111) and several surface-confined guests were measured in aqueous medium by single molecule force spectroscopy using an atomic force microscope. Anilyl, toluidyl, tert-butylphenyl, and adamantylthio... |
14759211 | Encapsulation of transition metal catalysts by ligand-template directed assembly. | Encapsulated transition metal catalysts are presented that are formed by templated self-assembly processes of simple building blocks such as porphyrins and pyridylphosphine and phosphite ligands, using selective metal-ligand interactions. These ligand assemblies coordinate to transition metals, leading to a new class o... |
14759210 | A calix[4]arene carceplex with four Rh2 4+ fasteners. | It is shown that a spheroidal carceplex can be assembled by linking two bowl-shaped calix[4]arenes via four dimetal units, (DAniF)(2)Rh(2) (DAniF = N,N'-di-p-anisylformamidinate), with a molecule (diethyl ether) or a cation (tetraethylammonium ion) trapped inside. The tetraethylammonium carceplex, 1b, has been characte... |
14759198 | A hexa-peri-hexabenzocoronene cyclophane: an addition to the toolbox for molecular electronics. | Cyclophanes with the largest-to-date polycyclic aromatic hydrocarbon (hexa-peri-hexabenzocoronene, HBC) to be entrained in such a structural motif are reported. The two disks are covalently captured by intermolecular ring-closing olefin metathesis of dienes in good yield. DSC, optical microscopy, and WAXD show the new ... |
14759190 | Molecular dynamics simulations of gas diffusion in metal-organic frameworks: argon in CuBTC. | The class of coordination polymers known as metal-organic frameworks (MOFs) has three-dimensional porous structures that are considered as a promising alternative to zeolites and other nanoporous materials for catalysis, gas adsorption, and gas separation applications. In this paper, we present the first study of gas d... |
14759173 | Self-assembled spiral nanoarchitecture and supramolecular chirality in Langmuir-Blodgett films of an achiral amphiphilic barbituric acid. | An amphiphilic barbituric acid derivative was found to form stable monolayers showing a clear phase transition at the air/water interface. It is interesting to find that the deposited Langmuir-Blodgett (LB) films of the compound showed circular dichroism (CD) although the molecule itself was achiral. AFM measurements o... |
14759165 | Effect of molecular oxygen on the variable-temperature 29Si MAS NMR spectra of zeolite-sorbate complexes. | Structure determinations of siliceous zeolite-sorbate host-guest complexes by solid-state NMR require highly resolved 29Si MAS NMR spectra. As the temperature is lowered, the 29Si MAS NMR spectra of many zeolite-sorbate complexes become broadened such that the resolution of the individual 29Si peaks is lost, limiting t... |
14759152 | A new insight into the formation of odor active carbonyls by thermally-induced degradation of phospholipids in self-assembly structures. | The role of molecular organization in heated aqueous dispersions of egg phosphatidylcholine (PC) and egg phosphatidylethanolamine (PE) was studied with respect to the formation of key odorants. Evidence was found for the crucial role of self-assembly structures adopted by phospholipid molecules on the quantitative comp... |
14760636 | Enantioseparation of new nucleoside analogs, related to d4T and acyclovir, by chiral capillary electrophoresis using highly sulfated beta-cyclodextrins. | Baseline separation of some new acyclic nucleosides which are potential antiviral agents was achieved using cyclodextrin capillary zone electrophoresis (CD-CZE). A method for the enantiomeric resolution of these compounds and determination of their enantiomeric purity was developed using anionic CDs (highly sulfated-CD... |
14757857 | The allelic modulation of apolipoprotein E expression by oestrogen: potential relevance for Alzheimer's disease. | <h4>Background</h4>The epsilon4 allele of the apolipoprotein E (APOE) gene is a major genetic risk factor for Alzheimer's disease but appears to be associated with greater risk in women than in men. Some studies suggest that the level of APOE may of its own modulate the risk for Alzheimer's disease. Sex differences and... |
14757750 | Cleavage furrow positioning. | To complete the cell cycle, the cleavage furrow draws the plasma membrane toward the cell center, pinching the cytoplasm into two lobes that are subsequently separated into two cells. The position of the cleavage furrow is induced by the mitotic spindle during early anaphase. Although the mechanism of cleavage furrow p... |
14758014 | A modified method using static head-space gas chromatography for determining the stability constants of 1-alkanol/alpha-cyclodextrin complexation. | A modification of the conventional static head-space gas chromatography method (SHSGC method) to determine stability constants for 1-alkanol/alpha-CD inclusion complexes was investigated. The 1 : 1 stability constants determined by this modified SHSGC method are in reasonable agreement with the corresponding values rep... |
14757163 | Antitumor AZA-anthrapyrazoles: biophysical and biochemical studies on 8- and 9-aza regioisomers. | Aza-bioisosteres of anthrapyrazoles (Aza-APs) bearing the C-N substitution at position 9 are powerful anticancer agents now in clinical trials. In contrast, their 8-substituted regioisomers are practically devoid of chemotherapeutic effects. To understand the molecular basis for a dramatically different response by oth... |
14755157 | A selective intra-HN(CA)CO experiment for the backbone assignment of deuterated proteins. | A modified version of the backbone TROSY based 3D HN(CA)CO experiment is presented that provides uniquely intraresidue correlation shift information, by efficiently suppressing the sequential connectivity data. The resulting reduction in the number of peaks decreases overlap and removes ambiguities in situations where ... |
14753801 | Encapsulation of cationic ruthenium complexes into a chiral self-assembled cage. | A chiral supramolecular assembly encapsulates the two cationic ruthenium sandwich complexes [CpRu(eta(6)-C(6)H(6))](+) and [CpRu(p-cymene)](+). The host-guest complexes K(11)[CpRu(eta(6)-C(6)H(6)) subset Ga(4)L(6)] (2) and K(11)[CpRu(p-cymene) subset Ga(4)L(6)] (3) were characterized by one- and two-dimensional NMR tec... |
18007408 | Addition of organochromium reagents to heteroaryl aldehydes. Synthesis of heteroaryl substituted bis-allyl ethers and homoallyl ethers. | Heteroaryl substituted allyl and homoallyl alcohols were synthesised with two different method. Synthesis of bis-allyl ethers and homoallyl ethers were carried out via reaction of allyl bromide with allyl alcohols and homoallyl alcohols, respectively. [2.3]-Wittig Rearrangement reactions of heteroaryl substituted bis-a... |
15252487 | Self-assembly sodalite-like framework. | The dense packing of shape complementary N-donor molecules dominates the self-assembly of coordination polymers possessing sodalite-like topology and supports nanosize molecular cages. |
15005797 | Quantitative differences in lipid raft components between murine CD4+ and CD8+ T cells. | <h4>Background</h4>Lipid rafts have been shown to play a role in T cell maturation, activation as well as in the formation of immunological synapses in CD4+ helper and CD8+ cytotoxic T cells. However, the differential expression of lipid raft components between CD4+ and CD8+ T cells is still poorly defined. To examine ... |
14755052 | Histone H3 lysine 9 methylation is required for DNA elimination in developing macronuclei in Tetrahymena. | Genome-wide DNA elimination accompanies development of the somatic macronucleus from the germ-line micronucleus during the sexual process of conjugation in the ciliated protozoan Tetrahymena thermophila. Small RNAs, referred to as "scan RNAs" (scnRNAs), that accumulate only during conjugation are highly enriched in the... |
14752123 | Hypercholesterolemia inhibits L-type calcium current in coronary macro-, not microcirculation. | Hypercholesterolemia (HC) is a mary risk factor for the development of coronary heart disease. Coronary ion regulation, especially calcium, is thought to be important in coronary heart disease development; however, the influence of high dietary fat and cholesterol on coronary arterial smooth muscle (CASM) ion channels ... |
14973571 | A monomolecularly imprinted dendrimer (MID) capable of selective binding with a tris(2-aminoethyl)amine guest through multiple functional group interactions. | A molecularly imprinted dendrimer (MID) with a colorimetric reporter group exhibits three-point binding of tris(aminoethyl)amine in THF with a K(assoc)= 3.3 x 10(6) M(-1). |
14752199 | Structures of the N-terminal modules imply large domain motions during catalysis by methionine synthase. | B(12)-dependent methionine synthase (MetH) is a large modular enzyme that utilizes the cobalamin cofactor as a methyl donor or acceptor in three separate reactions. Each methyl transfer occurs at a different substrate-binding domain and requires a different arrangement of modules. In the catalytic cycle, the cobalamin-... |
14747900 | Solvent extraction of amino acids into a room temperature ionic liquid with dicyclohexano-18-crown-6. | Amino acids Trp, Gly, Ala, Leu are extracted efficiently from aqueous solution at pH 1.5-4.0 (Lys and Arg at pH 1.5-5.5) into the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF(6)) with dicyclohexano-18-crown-6 (CE). The most hydrophilic amino acids such as Gly are extracted as ef... |
14765261 | A novel synthesis of chiral rotaxanes via covalent bond formation. | Chiral rotaxanes composed of the asymmetric crownophane incorporating two hydroxy groups as a rotor moiety and the asymmetric axis were effectively synthesized via covalent bond formation, i.e. tandem Claisen rearrangement, esterification, and aminolysis. |
14973573 | A host-guest complex between a metal-organic cyclotriveratrylene analog and a polyoxometalate: [Cu6(4,7-phenanthroline)8(MeCN)4]2PM12O40(M = Mo or W). | The synthesis and crystal structure of Cu(6)(4,7-phenanthroline)(8)(MeCN)(4)(6+) a novel Cu(i)-molecular hexamer is described in which the metal cations and phenanthroline molecules self-assemble into a dimer of shallow triangular-shaped bowls, within which are located large spherical polyoxometalate anions PM(12)O(40)... |
15252521 | Protonation and coordination properties towards Zn(II), Cd(II) and Hg(II) of a phenanthroline-containing macrocycle with an ethylamino pendant arm. | Protonation and Zn(II), Cd(II) and Hg(II) coordination with the ligand 5-aminoethyl-2,5,8-triaza-[9]-10,23-phenanthrolinophane (L2), which contains an aminoethyl pendant attached to a phenanthroline-containing macrocycle, have been investigated by means of potentiometric, 1H NMR and spectrofluorimetric titrations in aq... |
15252518 | Polymeric silver(I) complexes with pyridyl dithioether ligands: experimental and theoretical investigations on the coordination properties of the ligands. | The reactions of four flexible tetradentate ligands, 1,3-bis(2-pyridylthio)propane (L1), 1,4-bis(2-pyridylthio)butane (L2), 1,5-bis(2-pyridylthio)pentane (L3) and 1,6-bis(2-pyridylthio)hexane (L4) with AgX (X = BF4-, ClO4-, PF6-, or CF3SO3-) lead to the formation of seven new complexes: [AgL1(BF4)]2 (1), [[AgL2](ClO4)]... |
14745040 | Kv1.3 potassium channels are localized in the immunological synapse formed between cytotoxic and target cells. | Membrane proteins of cytotoxic T cells specifically reorganize to form an immunological synapse (IS) on interaction with their specific target. In this paper, we investigated the redistribution of Kv1.3 channels, which are the dominant voltage-gated potassium channels, in the plasma membrane of allogen-activated human ... |
14745003 | Coat protein regulates formation of replication complexes during tobacco mosaic virus infection. | The genome of tobacco mosaic virus (TMV) encodes replicase protein(s), movement protein (MP), and capsid protein (CP). On infection, one or more viral proteins direct the assembly of virus replication complexes (VRCs), in association with host-derived membranes. The impact of CP-mediated resistance on the structures of... |
14744995 | Massive thymic deletion results in systemic autoimmunity through elimination of CD4+ CD25+ T regulatory cells. | Incomplete deletion of KRN T cells that recognize the ubiquitously expressed self-antigen glucose-6-phosphate-isomerase (GPI) initiates an anti-GPI autoimmune cascade in K/BxN mice resulting in a humorally mediated arthritis. Transgenic (Tg) expression of a KRN T cell receptor (TCR) agonist under the major histocompati... |
14745001 | Noninvasive two-photon imaging reveals retinyl ester storage structures in the eye. | Visual sensation in vertebrates is triggered when light strikes retinal photoreceptor cells causing photoisomerization of the rhodopsin chromophore 11-cis-retinal to all-trans-retinal. The regeneration of preillumination conditions of the photoreceptor cells requires formation of 11-cis-retinal in the adjacent retinal ... |
14765265 | A copper-complexed rotaxane in motion: pirouetting of the ring on the millisecond timescale. | A new bistable rotaxane, consisting of a 2,2'-bipyridine-containing thread and a ring incorporating both a bidentate chelate and a tridentate fragment, has been prepared; this complex undergoes an electrochemically driven pirouetting motion of the ring around the axis which takes place on the millisecond timescale, i.e... |
14765213 | H-Bonded complexes of adenine with Rebek imide receptors are stabilised by cation-pi interactions and destabilised by stacking with perfluoroaromatics. | A series of Rebek imide receptors with naphthalene or heteroaromatic platforms attached by amide or ester linkers have been prepared from the corresponding acyl chloride or anhydride; the X-ray crystal structure of the receptor-derived anhydride reveals a supramolecular H-bonded helix formation in the crystal; the comp... |
14745712 | P75 tumor necrosis factor-receptor shedding occurs as a protective host response during African trypanosomiasis. | In experimental murine trypanosomiasis, resistance is often scored as the capacity to control peak parasitemia levels, which results in prolonged survival. Infection-induced pathology has not systematically been used as a resistance criterion. Because this parameter could be the most relevant for comparative analysis o... |
14745515 | Identification of an antigenic peptide derived from the cancer-testis antigen NY-ESO-1 binding to a broad range of HLA-DR subtypes. | NY-ESO-1 is a SEREX-defined cancer-testis antigen of which several MHC I, but only few MHC II-restricted epitopes have been identified. Searching for highly promiscuous MHC II-restricted peptides that might be suitable as a CD4+ stimulating vaccine for many patients, we used the SYFPEITHI algorithm and identified an NY... |
14742719 | Identification of a novel sequence in PDZ-RhoGEF that mediates interaction with the actin cytoskeleton. | Small GTPases of the Rho family are crucial regulators of actin cytoskeleton rearrangements. Rho is activated by members of the Rho guanine-nucleotide exchange factor (GEF) family; however, mechanisms that regulate RhoGEFs are not well understood. This report demonstrates that PDZ-RhoGEF, a member of a subfamily of Rho... |
14742718 | Dinitroanilines bind alpha-tubulin to disrupt microtubules. | Protozoan parasites are remarkably sensitive to dinitroanilines such as oryzalin, which disrupt plant but not animal microtubules. To explore the basis of dinitroaniline action, we isolated 49 independent resistant Toxoplasma gondii lines after chemical mutagenesis. All 23 of the lines that we examined harbored single ... |
14742716 | Association with membrane protrusions makes ErbB2 an internalization-resistant receptor. | In contrast to the epidermal growth factor (EGF) receptor, ErbB2 is known to remain at the plasma membrane after ligand binding and dimerization. However, why ErbB2 is not efficiently down-regulated has remained elusive. Basically, two possibilities exist: ErbB2 is internalization resistant or it is efficiently recycle... |
14995640 | Neutral polymer slow mode may signify an incipient growth-frustrated domain-forming glass. | Kivelson, et al. [J. Chem. Phys. 101, 2391 (1994)] propose a model for glass-forming liquids based on the potential existence of frustration-limited structures. Frustration-limited structures are equilibrium supramolecular assemblages. The maximum size of an assemblage is limited by geometric constraints. Here I propos... |
14770236 | NMR relaxometric study of new Gd(III) macrocyclic complexes and their interaction with human serum albumin. | Five novel Gd(iii) complexes based on the structure of the heptadentate macrocyclic 1,4,7,10-tetraazacyclododecane-1,4,7-triacetic acid (DO3A) ligand have been synthesized and their (1)H and (17)O NMR relaxometric properties investigated in detail. The complexes have been functionalised on the secondary nitrogen atom o... |
14734847 | Supramolecular assembling using synthons with NH-CO(S)-CS-NH and NH-CO-CO-NH functionalities: crystal structures of (S,S)-N,N'-monothiooxalyldileucine methyl ester and its dithio analogue. | To compare the structural properties of oxalamide and thiooxalamide groups in the formation of hydrogen bonds suitable for supramolecular assemblies a series of retropeptides was studied. Some of them, having oxalamide bridges, are gelators of organic solvents and water. However, retropeptides with oxygen replaced by t... |
14734846 | Symmetrically 4,6-disubstituted 2-aminopyrimidines and 2-amino-5-nitrosopyrimidines: interplay of molecular, molecular-electronic and supramolecular structures. | The structures of six symmetrically 4,6-disubstituted 2-aminopyrimidines, four of them containing a 5-nitroso substituent, have been determined. The nitroso compounds, in particular, exhibit polarized molecular-electronic structures leading to extensive charge-assisted hydrogen bonding. The intermolecular interactions ... |
14734845 | Adducts of 1,4,8,11-tetraazacyclotetradecane with carboxylic acids: hydrogen-bonded supramolecular structures in two or three dimensions. | Four solvated salt-type adducts derived from cyclam (1,4,8,11-tetraazacyclotetradecane) and carboxylic acids have been structurally characterized. In the salt derived from adamantane-1-carboxylic acid, 4,11-diaza-1,8-diazoniacyclotetradecane bis(adamantane-1-carboxylate) tetrahydrate, (1) (monoclinic, P2(1)/c, Z' = 0.5... |
14993949 | Synthesis of cycloalkynes via photochemical decarboxylation of omega-phthalimidoalkynoates. | The photodecarboxylation reactions of omega-phthalimidoalkynoates have been studied and the influence of the geometrically restricted acetylene linker on the photocyclization efficiency investigated. Less flexible starting materials give solely CO(2)H/H-exchange products in good yields. In contrast, derivatives with ap... |
14734816 | Highly sensitive amperometric detection of genomic DNA in animal tissues. | A simple and highly sensitive method for the detection of genomic DNA in tissue samples is described. It is based on amperometric detection of target DNA by forming an analyte/polymeric activator bilayer on a gold electrode. The biotinylated target DNA is hybridized to oligonucleotide capture probes immobilized on the ... |
14734645 | Apolipoprotein A-1 interaction with plasma membrane lipid rafts controls cholesterol export from macrophages. | Cholesterol efflux to apolipoprotein A-1 (apoA-1) from cholesterol-loaded macrophages is an important anti-atherosclerotic mechanism in reverse cholesterol transport. We recently provided kinetic evidence for two distinct pathways for cholesterol efflux to apoA-1 [Gaus et al. (2001) Biochemistry 40, 9363]. Cholesterol ... |
14770221 | Efficient resolution of 2,2'-dihydroxy-1,1'-binaphthyl by inclusion complexation with chiral N-(3-chloro-2-hydroxypropyl)-N,N,N-trimethylammonium chloride. | The complete resolution of 2,2[prime or minute]-dihydroxy-1,1[prime or minute]-binaphthyl into its enantiomers by inclusion complexation with a commercially available derivative of choline, is reported. The two enantiomers are recovered in >99% ee from the inclusion complexes by simple dissolution in a diethyl ether-wa... |
14765232 | Construction of porphyrin-cyclodextrin self-assembly with molecular wedge. | A new host porphyrin bearing four permethyl-beta-cyclodextrin moieties for multi-porphyrin assembly forms a unique 2 : 2 assembly with the tetra-anion of tetrakis(p-sulfonylphenyl)porphyrin (TPPS) in aqueous solution. |
14765220 | A novel chiral terpyridine macrocycle as a fluorescent sensor for enantioselective recognition of amino acid derivatives. | Terpyridine macrocycle 1 is shown to be a strong chelating agent for organic ammonium salts and also a useful chromophore in fluorescent sensing. It exhibits very good enantioselectivity (K(obs)(S)/K(obs)(R)= 3.8) in chiral discrimination of alpha-phenylglycine methyl ester hydrochloride (PhEtOMe). |
14732694 | A structure-based model for ligand binding and dimerization of EGF receptors. | On the basis of the 3D structures of the extracellular ligand-binding domains of the epidermal growth factor (EGF) receptor (EGFR) and ErbB3, a mechanism has been proposed for how the extracellular region of the EGFR is maintained in an autoinhibited configuration and for how EGF binding induces EGFR dimerization and a... |
15252528 | Design and coordination behavior of the first selective recognition ligand of 147Pm(III). | A new amide tripodal ligand, 6-[2-(2-diethylamino-2-oxoethoxy)ethyl]-N,N,12-triethyl-11-oxo-3,9-dioxa-6,12-diazatetradecanamide (4) has been designed and synthesized for the recognition of rare earth ions. Three representative complexes of trivalent lighter (La), middle (Gd), and heavier (Er) rare earth ions with 4 wer... |
15252511 | Robust hydrogen-bonded self-assemblies from biimidazole complexes. Synthesis and structural characterization of [M(biimidazole)2(OH2)2]2+ (M = Co2+, Ni2+) complexes and carboxylate modules. | A robust heteromeric hydrogen-bonded synthon [R2(2) (9)-Id] is exploited to drive the modular self-assembly of four coordination complexes [M(H2biim)2(OH2)2]2+ (M = Co2+, Ni2+) and carboxylate counterions. This strategy allowed us to build molecular architectures of 0-, 1-, and 2-dimensions. A hydrogen-bonded 2D-networ... |
14729572 | A glutamate receptor-interacting protein homolog organizes muscle guidance in Drosophila. | During Drosophila embryogenesis, developing muscles extend growth-cone-like structures to navigate toward specific epidermal attachment sites. Here, we show that the homolog of Glutamate Receptor-Interacting Proteins (DGrip) acts as a key component of proper muscle guidance. Mutations in dgrip impair patterning of vent... |
14729661 | Expression of caveolin-1 enhances cholesterol efflux in hepatic cells. | HepG2 cells were stably transfected with human caveolin-1 (HepG2/cav cells). Transfection resulted in expression of caveolin-1 mRNA, a high abundance of caveolin-1 protein, and the formation of caveolae on the plasma membrane. Cholesterol efflux from HepG2/cav cells was 280 and 45% higher than that from parent HepG2 ce... |
14995643 | Sequence variability of proteins evolutionarily constrained by solution-thermodynamic function. | Focusing on silk fibroin and hemoglobin molecules as templates, we model protein homolog dispersal across sequence-fitness landscapes determined by solution thermodynamics. Landscapes are constructed by inspecting an idealized theoretical phase topology associated with sequence length and hydrophobic-polar composition,... |
15252510 | Self-assembly of molecular squares based on easy-to-prepare multidentate Schiff base ligands. | The choice of ligands with different spacer length and coordination orientation leads to size, shape and packing differences between two self-assembled molecular squares [Zn4H8L1(4)][PF6]5[NO3]3.S (1) and [Zn4H8L2(4)][PF6]6[NO3]2.S (2) (S = solvent), formed from Zn(NO3)2 and two easy-to-prepare bistridentate Schiff-bas... |
14726413 | Verapamil increases the apolipoprotein-mediated release of cellular cholesterol by induction of ABCA1 expression via Liver X receptor-independent mechanism. | <h4>Objective</h4>Release of cellular cholesterol and phospholipid mediated by helical apolipoprotein and ATP-binding cassette transporter (ABC) A1 is a major source of plasma HDL. We investigated the effect of calcium channel blockers on this reaction.<h4>Methods and results</h4>Expression of ABCA1, apoA-I-mediated ce... |
14724296 | Complex and dynamic redistribution of NF-kappaB signaling intermediates in response to T cell receptor stimulation. | The central zone of the supramolecular activation cluster (c-SMAC) is a zone of T cell receptor (TCR) enrichment that forms at a T cell/antigen-presenting cell (APC) junction in response to antigen stimulation. We demonstrate that there is a surprisingly complex relocalization process that brings PKC and Bcl10, two int... |
14724226 | Brain uptake of the glucagon-like peptide-1 antagonist exendin(9-39) after intranasal administration. | Exendin, a member of the glucagon-like peptide-1 family, and its antagonist exendin(9-39) affect cognition and neuronal survival after their intranasal delivery. Here, we examined the uptake of radioactively labeled exendin(9-39) (I-Ex) by the olfactory bulbs, brain (minus pineal, pituitary, and olfactory bulb), cerebr... |
14724204 | Membrane cholesterol modulates dihydropyridine receptor function in mice fetal skeletal muscle cells. | Caveolae and transverse (T-) tubules are membrane structures enriched in cholesterol and glycosphingolipids. They play an important role in receptor signalling and myogenesis. The T-system is also highly enriched in dihydropyridine receptors (DHPRs), which control excitation-contraction (E-C) coupling. Recent results h... |
14722355 | A serine protease zymogen functions as a pattern-recognition receptor for lipopolysaccharides. | Bacterial lipopolysaccharide (LPS)-induced exocytosis of granular hemocytes is a key component of the horseshoe crab's innate immunity to infectious microorganisms; stimulation by LPS induces the secretion of various defense molecules from the granular hemocytes. Using a previously uncharacterized assay for exocytosis,... |
14747859 | Effects of an 8-bromodeoxyguanosine incorporation on the parallel quadruplex structure [d(TGGGT)]4. | NMR, molecular dynamics and mechanics calculations, and CD spectroscopy were used to characterise three tetramolecular quadruplex complexes: [d(TG(Br)GGT)](4), [d(TGG(Br)GT)](4) and [d(TGGG(Br)T)](4), where G(Br) indicates an 8-bromoguanine residue. All three quadruplexes are characterised by a 4-fold symmetry with all... |
14718572 | CRB3 binds directly to Par6 and regulates the morphogenesis of the tight junctions in mammalian epithelial cells. | Crumbs is an apical transmembrane protein crucial for epithelial morphogenesis in Drosophila melanogaster embryos. A protein with all the characteristics for a Crumbs homologue has been identified from patients suffering from retinitis pigmentosa group 12, but this protein (CRB1) is only expressed in retina and some pa... |
14718556 | Expression profiling of mammalian male meiosis and gametogenesis identifies novel candidate genes for roles in the regulation of fertility. | We report a comprehensive large-scale expression profiling analysis of mammalian male germ cells undergoing mitotic growth, meiosis, and gametogenesis by using high-density oligonucleotide microarrays and highly enriched cell populations. Among 11,955 rat loci investigated, 1268 were identified as differentially transc... |
14718651 | Formation of amyloid fibrils from fully reduced hen egg white lysozyme. | The fully reduced hen egg white lysozyme (HEWL), which is a good model of random coil structure, has been converted to highly organized amyloid fibrils at low pH by adding ethanol. In the presence of 90% (v/v) ethanol, the fully reduced HEWL adopts beta-sheet secondary structure at pH 4.5 and 5.0, and an alpha-to-beta ... |
14767113 | [5,10,15,20-Tetrakis(pentafluorophenyl)porphyrinato]iron(II) benzene disolvate. | The title compound, [Fe(C(44)H(8)F(20)N(4))].2C(6)H(6), contains a four-coordinated Fe(II) atom, which lies on a center of symmetry. The porphyrin macrocycle is planar, and the Fe-N bond distances are in the range 1.9891 (13)-1.9982 (13) A. The spin state of the Fe(II) atom is intermediate (S = 1), as confirmed by NMR ... |
15252535 | What kinds of three-dimensional nets are possible with tris-chelated metal complexes as building blocks? | Tris-chelated metal complexes with octahedral geometry are sometimes used as building blocks for "self assembly" and "crystal engineering". These versatile building blocks easily form honey-comb type 2D nets. However, in this Perspective we discuss the different types of 3D nets that can be formed with these starting m... |
14715922 | Hydration of short DNA, RNA and 2'-OMe oligonucleotides determined by osmotic stressing. | Studies on hydration are important for better understanding of structure and function of nucleic acids. We compared the hydration of self-complementary DNA, RNA and 2'-O-methyl (2'-OMe) oligonucleotides GCGAAUUCGC, (UA)6 and (CG)3 using the osmotic stressing method. The number of water molecules released upon melting o... |
14713952 | Ubiquitination and translocation of TRAF2 is required for activation of JNK but not of p38 or NF-kappaB. | TRAF2 is a RING finger protein that regulates the cellular response to stress and cytokines by controlling JNK, p38 and NF-kappaB signaling cascades. Here, we demonstrate that TRAF2 ubiquitination is required for TNFalpha-induced activation of JNK but not of p38 or NF-kappaB. Intact RING and zinc finger domains are req... |
14747867 | Factors influencing solvent adduct formation by calixarenes in the solid state. | Structural studies of seven very differently functionalised derivatives of calix[4]arene have been used to provide an analysis of the numerous factors which may influence solvent adduct formation by calixarenes. Evidence is presented that even where a solvent guest is included within the calixarene cavity, interactions... |
14740059 | A new biotinylated tris bipyridinyl iron(II) complex as redox biotin-bridge for the construction of supramolecular biosensing architectures. | The bioaffine immobilization of several avidin layers on an electrode modified by a biotinylated polymer was accomplished by the first biotinylated redox bridge consisted of a tris(bipyridyl)iron(II) complex bearing six pre-oriented biotin groups. |
14715898 | High-resolution molecular structure of a peptide in an amyloid fibril determined by magic angle spinning NMR spectroscopy. | Amyloid fibrils are self-assembled filamentous structures associated with protein deposition conditions including Alzheimer's disease and the transmissible spongiform encephalopathies. Despite the immense medical importance of amyloid fibrils, no atomic-resolution structures are available for these materials, because t... |
14711376 | Syndecans in tumor cell adhesion and signaling. | Anchorage of cells to "heparin"--binding domains that are prevalent in extracellular matrix (ECM) components is thought to occur primarily through the syndecans, a four-member family of transmembrane heparan sulfate proteoglycans that communicate environmental cues from the ECM to the cytoskeleton and the signaling app... |
14711812 | Dual mechanisms for shedding of the cellular prion protein. | The cellular prion protein (PrP(C)) is essential for the pathogenesis and transmission of prion diseases. Whereas the majority of PrP(C) is bound to the cell membrane via a glycosylphosphatidylinositol (GPI) anchor, a secreted form of the protein has been identified. Here we show that PrP(C) can be shed into the medium... |
15252552 | Self-assembly of novel macrocyclic aminomethylphosphines with hydrophobic intramolecular cavities. | Novel macroheterocyclic tetraphosphines, namely, 1,1',5,5'-bis(arylene)-bis(1,5-diaza-3,7-diphosphacyclooctanes) 2-6, were obtained without the use of high-dilution techniques or any matrix by the reaction of bis(hydroxymethyl)organylphosphines with primary aromatic diamines containing two p-phenylene fragments linked ... |
15252537 | Unexpected formation of a novel macrocyclic tetraphosphine: (RSSR)-1,9-dibenzyl-3,7,11,15-tetramesityl-1,9-diaza-3,7,11,15-tetraphosphacyclohexadecane. | The title compound was synthesised in moderate yield via stereoselective self-assembly of two bisphosphine, four formaldehyde and two primary amine molecules. |
14740050 | Anti-viral cyclam macrocycles : rapid zinc uptake at physiological pH. | NMR and UV-vis spectroscopic studies show that Zn(II) binds to cyclam rapidly at micromolar concentrations, an observation relevant to the anti-viral activity and co-receptor binding of anti-HIV cyclams. |
14709674 | DNA nanotubes self-assembled from triple-crossover tiles as templates for conductive nanowires. | DNA-based nanotechnology is currently being developed as a general assembly method for nanopatterned materials that may find use in electronics, sensors, medicine, and many other fields. Here we present results on the construction and characterization of DNA nanotubes, a self-assembling superstructure composed of DNA t... |
14709550 | A new group of antifungal and antibacterial lipopeptides derived from non-membrane active peptides conjugated to palmitic acid. | We report on the synthesis, biological function, and a plausible mode of action of a new group of lipopeptides with potent antifungal and antibacterial activities. These lipopeptides are derived from positively charged peptides containing d- and l-amino acids (diastereomers) that are palmitoylated (PA) at their N termi... |
15252555 | Coordination features of ditopic oxa-azamacrocycles toward Ni(II) and Co(II). Dioxygen uptake by their dinuclear Co(II) complexes. | The coordination properties of the ditopic oxa-aza macrocycles L1-L3 toward Ni(II) and Co(II) have been investigated by means of potentiometric and UV-vis spectrophotometric measurements. L1-L3 contain two triamine and/or tetraamine chains separated by two dioxa chains and form both mono- and dinuclear complexes in aqu... |
14704272 | RF2b, a rice bZIP transcription activator, interacts with RF2a and is involved in symptom development of rice tungro disease. | The phloem-specific promoter of rice tungro bacilliform virus (RTBV) is regulated in part by sequence-specific DNA-binding proteins that bind to Box II, an essential cis element. Previous studies demonstrated that the bZIP protein RF2a is involved in transcriptional regulation of the RTBV promoter. Here we report the i... |
14704269 | The second extracellular loop of the dopamine D2 receptor lines the binding-site crevice. | The binding site of the dopamine D(2) receptor (D2R), like those of homologous rhodopsin-like G protein-coupled receptors (GPCRs) that bind small molecules, is contained within a water-accessible crevice formed among its seven transmembrane segments (TMs). The high-resolution structure of bovine rhodopsin, however, rev... |
14704359 | Ligase-mediated construction of branched DNA strands: a novel DNA joining activity catalyzed by T4 DNA ligase. | Branched nucleic acid strands exist as intermediates in certain biological reactions, and bifurcating DNA also presents interesting opportunities in biotechnological applications. We describe here how T4 DNA ligase can be used for efficient construction of DNA molecules having one 5' end but two distinct 3' ends that e... |
14704351 | Coenzyme B12 riboswitches are widespread genetic control elements in prokaryotes. | Recent studies have begun to reveal that numerous fundamental metabolic pathways in bacteria are regulated by riboswitches residing within certain messenger RNAs. These riboswitches selectively bind metabolites and modulate gene expression in response to changing ligand concentrations. Previously, we provided evidence ... |
14704349 | Formation of DNA nanoparticles in the presence of novel polyamine analogues: a laser light scattering and atomic force microscopic study. | We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 ... |
14704231 | Localization of VEGFR-2 and PLD2 in endothelial caveolae is involved in VEGF-induced phosphorylation of MEK and ERK. | To clarify the role of caveolae in VEGF/VEGF receptor-2 (VEGFR-2)-mediated signaling cascades, primary cultured human umbilical vein endothelial cells (HUVECs) were fractionated to isolate caveolae-enriched cell membranes. Interestingly, VEGFR-2, phospholipase D2 (PLD2), and Ras were enriched in caveolae-enriched fract... |
32214567 | Recent developments in the use of transgenic plants for the production of human therapeutics and biopharmaceuticals. | In recent years there has been a dramatic increase in the application of plant biotechnology for the production of a variety of commercially valuable simple and complex biological molecules (biologics) for use in human and animal healthcare. Transgenic whole plants and plant cell culture systems have been developed tha... |
27366596 | Direct Space Structure Solution Applications. | The crystal structures of 2,4,6-triisopropylbenzenesulfonamide, 1,2,3-trihydroxybenzene-hexamethylenetetramine (1/1), 5-bromonicotinic acid and chlorothalonil form II have been solved from x-ray powder diffraction data, by application of a direct space structure solution approach using the Monte Carlo method and confir... |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.