id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
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11673993 | Chiral recognition of helical metal complexes by modified cyclodextrins. | Chirality of metal complexes M(phen)3(n+) (M = Ru(II), Rh(III), Fe(II), Co(II), and Zn(II), and phen = 1,10-phenanthroline) is recognized by heptakis(6-carboxymethylthio-6-deoxy)-beta-cyclodextrin heptaanion (per-CO2(-)-beta-CD) and hexakis(2,3,6-tri-O-methyl)-alpha-cyclodextrin (TMe-alpha-CD) in D2O. The binding const... |
11673988 | Dopamine interaction in the absence and in the presence of Cu2+ ions with macrocyclic and macrobicyclic polyamines containing pyrazole units. Crystal structures of [Cu2(L1)(H2O)2](ClO4)4 and [Cu2(H-1L3)](ClO4)3*2H2O. | The interaction with Cu2+ and dopamine of three polyazacyclophanes containing pyrazole fragments as spacers is described. Formation of mixed complexes Cu2+-macrocycle-dopamine has been studied by potentiometric methods in aqueous solution. The crystal structures of the complexes [Cu2(L1)(H2O)2](ClO4)4*2H2O (4) (L1 = 13... |
11673986 | Cu(0) nanoclusters derived from poly(propylene imine) dendrimer complexes of Cu(II). | A family of diaminobutane core, poly(propylene imine) dendrimers coordinated to Cu(II), DAB-Am(n)-Cu(II)x (n = 4, 8, 16, 32, 64, x = n/2), was studied by means of extended X-ray absorption fine structure (EXAFS) and X-ray absorption near-edge structure (XANES) spectroscopies. The geometry of the dipropylene triamine (d... |
11673978 | Complexation-induced unfolding of heterocyclic ureas. Simple foldamers equilibrate with multiply hydrogen-bonded sheetlike structures. | The synthesis and conformational studies of heterocyclic ureas (amides) 1-7 and their concentration-dependent unfolding to form multiply hydrogen-bonded complexes are described. Ureas 1 and 7 were prepared by reacting 2-aminopyridine and aminonaphthyridine 25, respectively, with triphosgene and 4-(dimethylamino)pyridin... |
11673879 | A comparison of fluorescamine and naphthalene-2,3-dicarboxaldehyde fluorogenic reagents for microplate-based detection of amino acids. | The use of appropriate fluorometric derivatization procedures is of considerable importance for accurate determination of amino acids in biological samples and in metal-assisted peptide hydrolysis reactions. It is especially critical for the relative fluorescence intensities (RFI) of equal amounts of amino acids to be ... |
11675782 | Selective assembly on a surface of supramolecular aggregates with controlled size and shape. | The realization of molecule-based miniature devices with advanced functions requires the development of new and efficient approaches for combining molecular building blocks into desired functional structures, ideally with these structures supported on suitable substrates 1-4. Supramolecular aggregation occurs spontaneo... |
11669545 | Cyclodextrin-assisted capillary electrophoretic resolution of 1,1'-bi-2-naphthol atropisomers. | Native beta- and gamma-cyclodextrin (CD), neutral beta-CD derivatives and ethylcarbonate derivatives of beta- and gamma-CD were used as stereoselective additives for CD-capillary zone electrophoresis (CZE) resolution of atropisomers of 1,1'-bi-(2-naphthol) (BN). CZE experiments at variable CD concentration allowed calc... |
11669514 | Separation of basic drug enantiomers by capillary zone electrophoresis using glucuronyl glucosyl beta-cyclodextrin as a chiral selector. | Separations of basic drug enantiomers have been investigated using glucuronyl glucosyl beta-cyclodextrin (GUG beta-CD) as a chiral selector in the background electrolyte by capillary zone electrophoresis. The effects of GUG beta-CD concentration and running buffer pH on the migration times and resolution of 16 basic dr... |
11669365 | Optimization strategies and modeling of separations of dansyl-amino acids by cyclodextrin-modified capillary electrophoresis. | Presented in this study is an approach to optimize conditions for capillary electrophoresis separations of multianalyte enantiomeric pairs (D- and L-dansyl (Dns)-amino acids) that involves the rational use of combinations of cyclodextrins (CDs) as enantioselective running buffer additives. Migration data is experimenta... |
11606220 | Identification of the molecular interaction site of amyloid beta peptide by using a fluorescence assay. | Beta-amyloid peptides (Abeta) are the main protein components of neuritic plaques and are important in the pathogenesis of Alzheimer's disease. It is reported that Abeta itself is not toxic; however, it becomes toxic to neuronal cells once it has aggregated into amyloid fibrils by peptide-peptide interactions. In this ... |
11606215 | Synthesis, isolation and characterization of Plasmodium falciparum antigenic tetrabranched peptide dendrimers obtained by thiazolidine linkages. | Different chemical alternatives were evaluated for obtaining immunogenic polypeptidic macromolecules which could then be used as vaccines. These were based on the ligation reaction between an unprotected immunogenic peptide and an unprotected multifunctional core peptide; polyantigens, designated dendrimers because the... |
11606214 | Conformation and other biophysical properties of cyclic antimicrobial peptides in aqueous solutions. | As a step towards understanding the mechanism of the biological activity of cyclic antimicrobial peptides, the biophysical properties and conformations of four membrane-active cyclic peptide antibiotics, based on gramicidin S (GS), were examined in aqueous environments. These cyclic peptides, GS10 [cyclo(VKLdYP)2], GS1... |
11606127 | Synthesis of sulfaphenazole derivatives and their use as inhibitors and tools for comparing the active sites of human liver cytochromes P450 of the 2C subfamily. | Twenty-three new derivatives of sulfaphenazole (SPA) were synthesized to further explore the topology of the active sites of human liver cytochromes P450 of the 2C subfamily and to find new selective inhibitors of these cytochromes. These compounds are derived from SPA by replacement of the NH(2) and H (of the SO(2)NH ... |
11606210 | Artificial chaperone mediated refolding of xylanase from an alkalophilic thermophilic Bacillus sp. Implications for in vitro protein renaturation via a folding intermediate. | To gain insight into the molecular aspects of unfolding/refolding of enzymes from extremophilic organisms, we have used xylanase from an alkalophilic thermophilic Bacillus as the model system. Kinetics of denaturation/renaturation were monitored using intrinsic fluorescence studies. The protein fluorescence measurement... |
11606331 | GABA receptors modulate trigeminovascular nociceptive neurotransmission in the trigeminocervical complex. | 1. GABA (gamma-aminobutyric acid) receptors involved in craniovascular nociceptive pathways were characterised by in vivo microiontophoresis of GABA receptor agonists and antagonists onto neurones in the trigeminocervical complex of the cat. 2. Extracellular recordings were made from neurones in the trigeminocervical c... |
11605658 | Structural and thermodynamic behavior of eukaryotic initiation factor 4E in supramolecular formation with 4E-binding protein 1 and mRNA cap analogue, studied by spectroscopic methods. | The structural and thermodynamic behavior of the complex formation of eIF4E with either or both mRNA cap analogue (m7GTP, m7GpppA, or m7GpppG) and 4EBP1 has been investigated by spectroscopic measurements. Although the circular dichroism (CD) spectrum of eIF4E was little affected by the association with any cap analogu... |
11605651 | Preparation and characterization of insulin-loaded acrylic hydrogels containing absorption enhancers. | The objectives of this study were to prepare insulin-loaded acrylic hydrogel formulations containing various absorption enhancers, to perform in vitro and in vivo characterization of these formulations, and to evaluate the factors which affecting insulin availability on rectal delivery of insulin using this hydrogel sy... |
11605649 | Molecular modelling and 1H-NMR: ultimate tools for the investigation of tolbutamide: beta-cyclodextrin and tolbutamide: hydroxypropyl-beta-cyclodextrin complexes. | A structural study of the inclusion compound of tolbutamide (TBM) with beta-cyclodextrin (beta-CD) and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was attempted by means of 1H-nuclear magnetic resonance (1H-NMR) experiments and computer molecular modelling. To establish the stoichiometry and stability constant of the ... |
11603979 | A model for sequential threading of alpha-cyclodextrin onto a guest: a complete thermodynamic and kinetic study in water. | The first variable-temperature and variable-pressure stopped-flow spectrophotometric study of the sequential threading of alpha-cyclodextrin (alpha-CD) onto the guest dye Mordant Orange 10, S, is reported. Complementary (1)H one-dimensional (1D) variable-temperature kinetic studies and two-dimensional (2D) rotating-fra... |
11603967 | Efficient, high-yield route to long, functionalized p-phenylene oligomers containing perfluorinated segments, and their cyclodimerizations by zirconocene coupling. | Linear oligophenylene diynes containing 6, 9, and 12 phenylene rings were synthesized in high yields using the nucleophilic aromatic substitution (S(N)Ar) of perfluoroarenes by aryllithium reagents as the key carbon-carbon bond-forming reaction. This reaction was demonstrated to proceed readily at low temperatures with... |
11603964 | Amplification of chirality: the "sergeants and soldiers" principle applied to dynamic hydrogen-bonded assemblies. | The amplification of supramolecular chirality has been studied in dynamic chiral hydrogen-bonded assemblies 1(3).(CA)(6) using "Sergeants and Soldiers" experiments. Previously, we have shown that chiral centers present in either the dimelamine component 1 or the cyanurate component CA quantitatively induce one handedne... |
11604269 | Improvement of some pharmaceutical properties of DY-9760e by sulfobutyl ether beta-cyclodextrin. | The interaction of DY-9760e, a novel cytoprotective agent, with sulfobutyl ether beta-cyclodextrin (SBE-beta-CyD) in phosphate buffered saline (PBS) at various pH and ionic-strengths was studied by spectroscopic methods and the solubility method, and the results were compared with that of 2-hydroxypropyl-beta-cyclodext... |
11604256 | Effect of passive and iontophoretic skin pretreatments with terpenes on the in vitro skin transport of piroxicam. | The enhancing effect of several terpenes (thymol, menthone and 1,8-cineole) in the percutaneous permeation of piroxicam (Px), either passive or iontophoretically, was investigated. These terpenes were applied, on the skin membrane, as a passive and iontophoretic skin pretreatment. Px was delivered from carbopol gels co... |
11602647 | T cell-independent interleukin 15Ralpha signals are required for bystander proliferation. | Cytokine driven or "bystander" proliferation of T cells occurs in vivo independently of major histocompatibility complex-T cell receptor interactions. This process may be important for supporting T cell homeostasis and facilitating T cell responses to microbial antigens, and may involve the cytokine interleukin (IL)-15... |
11601972 | Monomeric solution structure of the prototypical 'C' chemokine lymphotactin. | Lymphotactin, the sole identified member of the C class of chemokines, specifically attracts T lymphocytes and natural killer cells. This 93-residue protein lacks 2 of the 4 conserved cysteine residues characteristic of the other 3 classes of chemokines and possesses an extended carboxyl terminus, which is required for... |
11599967 | (6,17-Dimethyl-8,15-diphenyldibenzo[b,i][1,4,8,11]-tetra-aza[14]annulenato)nickel(II) in solids: two guest-free polymorphs and inclusion compounds with methylene chloride and fullerene (C(60))-carbon disulfide. | Two guest-free polymorphs and two inclusion compounds of the macrocyclic title complex [NiL] have been isolated and characterized with single-crystal and/or powder XRD, solid-state (13)C NMR, and other methods. The inclusion compound with methylene chloride, [NiL](CH(2)Cl(2)), is stable in air and thermally stable up t... |
11599958 | Ring-opening and meso substitution from the reaction of cyanide ion with zinc verdohemes. | The reactivity of zinc verdoheme, [Zn(II)(OEOP)](O(2)CCH(3)) where OEOP is the monoanion of octaethyl-5-oxaporphyrin, with cyanide ion has been shown to be a complex process that involves not only the expected ring-opening of the macrocycle, as occurs with other nucleophiles (methoxide, methanethiolate, dimethylamide),... |
11598206 | Vps26p, a component of retromer, directs the interactions of Vps35p in endosome-to-Golgi retrieval. | Endosome-to-Golgi retrieval of the carboxypeptidase Y receptor Vps10p is mediated by a recently discovered membrane coat complex termed retromer. Retromer comprises five conserved proteins: Vps35p, Vps29p, Vps5p, Vps17p, and Vps26p. Vps35p recognizes cargo molecules such as Vps10p and interacts strongly with Vps29p. Vp... |
11598183 | Lipid rafts act as specialized domains for tetanus toxin binding and internalization into neurons. | Tetanus (TeNT) is a zinc protease that blocks neurotransmission by cleaving the synaptic protein vesicle-associated membrane protein/synaptobrevin. Although its intracellular catalytic activity is well established, the mechanism by which this neurotoxin interacts with the neuronal surface is not known. In this study, w... |
11597245 | Formation of macrocycles via ring-closing olefin metathesis. | The enhanced metathesis activity of 1,3-dimesityl-4,5-dihydroimidazole-2-ylidene ruthenium carbene catalyst 3 significantly increases the feasibility of synthesizing macrocyclic compounds. Catalyst 3 exhibits sufficient activity in RCM to dimerize alpha,beta-unsaturated ester substrates and afford the corresponding hea... |
11597230 | Extraannular fluorinated calixarenes: regiospecificity of the deoxofluorination reactions of bis(spirodienol) derivatives. | A new route for the partial displacement of OH groups of p-tert-butylcalixarene via spirodienol derivatives is described. NaBH(4) reduction of the bis(spirodienone) calixarene derivatives 2a-2c afforded the corresponding bis(spirodienols) 3a-3c in stereospecific fashion. (1)H NMR NOESY spectroscopy indicated that in th... |
11597226 | Self-assembly of novel [3]- and [2]rotaxanes with two different ring components: donor-acceptor and hydrogen bonding interactions and molecular-shuttling behavior. | Three of the first kind of hetero[3]rotaxanes, which comprise one linear component and one neutral and one tetracationic ring component, have been assembled by using the intermolecular hydrogen bonding and donor-acceptor interactions. Three neutral [2]rotaxanes and three tetracationic [2]rotaxanes have also been synthe... |
11597222 | Efficient photocyclization of o-alkylbenzaldehydes in the solid state: direct observation of E-xylylenols en route to benzocyclobutenols. | The photocyclization to benzocyclobutenols of o-alkyl aromatic aldehydes that are predestined for gamma-hydrogen abstraction is found to occur efficiently in the solid state; in contrast, solution-phase photolysis is known to afford a mixture of several products. It is shown that mesitaldehyde, which is a liquid, also ... |
11597206 | NMR diffusion spectroscopy as a measure of host-guest complex association constants and as a probe of complex size. | The complexes of cyclohexylacetic acid and cholic acid with beta-cyclodextrin were studied by NMR diffusion coefficient measurements. The diffusion coefficient of the 1:1 cyclohexylacetic acid/beta-cyclodextrin complex, K(a) = 1800 +/- 100 M(-1), is slightly slower (3.23 +/- 0.07 x 10(-6) cm(2) s(-1)) than that of beta... |
11597203 | Supramolecular daisy chains. | Two series of self-complementary daisy chain monomers, in which a secondary ammonium ion-containing arm is grafted onto a macrocycle with either a [24]- or [25]crown-8 constitution, have been synthesized. In the solid- and 'gas'-phases, the parent [24]crown-8-based monomer forms dimeric superstructures, as revealed by ... |
11598017 | The hnRNP A1 protein regulates HIV-1 tat splicing via a novel intron silencer element. | The generation of >30 different HIV-1 mRNAs is achieved by alternative splicing of one primary transcript. The removal of the second tat intron is regulated by a combination of a suboptimal 3' splice site and cis-acting splicing enhancers and silencers. Here we show that hnRNP A1 inhibits splicing of this intron via a ... |
11594813 | A new fluorescent chemosensor for copper ions based on tripeptide glycyl-histidyl-lysine (GHK). | [structure: see text]. A new fluorescent chemosensor for Cu2+ ions was synthesized by modifying the tripeptide glycyl-histidyl-lysine (GHK) with 9-carbonylanthracene via the standard Fmoc solid-phase peptide synthesis method. While significant fluorescence quenching was observed from the molecule upon binding with Cu2+... |
11594731 | Two distinct populations of tumor necrosis factor-stimulated gene-6 protein in the extracellular matrix of expanded mouse cumulus cell-oocyte complexes. | After the luteinizing hormone surge, the cumulus cell-oocyte complexes (COCs) in the preovulatory follicles produce a viscoelastic extracellular matrix, a process that requires the synthesis of hyaluronan as well as the incorporation of some components of the inter-alpha-trypsin inhibitor (IalphaI) family. In this stud... |
11593005 | Crystal structure of the central region of bovine fibrinogen (E5 fragment) at 1.4-A resolution. | The high-resolution crystal structure of the N-terminal central region of bovine fibrinogen (a 35-kDa E(5) fragment) reveals a remarkable dimeric design. The two halves of the molecule bond together at the center in an extensive molecular "handshake" by using both disulfide linkages and noncovalent contacts. On one fac... |
11592996 | Hierarchical self-assembly of chiral rod-like molecules as a model for peptide beta -sheet tapes, ribbons, fibrils, and fibers. | A generic statistical mechanical model is presented for the self-assembly of chiral rod-like units, such as beta-sheet-forming peptides, into helical tapes, which with increasing concentration associate into twisted ribbons (double tapes), fibrils (twisted stacks of ribbons), and fibers (entwined fibrils). The finite f... |
11592878 | Adsorption dynamics of gases and vapors on the nanoporous metal organic framework material Ni2(4,4'-bipyridine)3(NO3)4: guest modification of host sorption behavior. | This study combines measurements of the thermodynamics and kinetics of guest sorption with powder X-ray diffraction measurements of the nanoporous metal organic framework adsorbent (host) at different adsorptive (guest) loadings. The adsorption characteristics of nitrogen, argon, carbon dioxide, nitrous oxide and ethan... |
11592625 | The effect of subthreshold prepulses on the recruitment order in a nerve trunk analyzed in a simple and a realistic volume conductor model. | The influence of subthreshold depolarizing prepulses on the threshold current-to-distance and the threshold current-to-diameter relationship of myelinated nerve fibers has been investigated. A nerve fiber model was used in combination with both a simple, homogeneous volume conductor model with a point source and a real... |
11591760 | Spatial organization of signal transduction molecules in the NK cell immune synapses during MHC class I-regulated noncytolytic and cytolytic interactions. | The cytolytic activity of NK cells is tightly regulated by inhibitory receptors specific for MHC class I Ags. We have investigated the composition of signal transduction molecules in the supramolecular activation clusters in the MHC class I-regulated cytolytic and noncytolytic NK cell immune synapses. KIR2DL3-positive ... |
11591392 | Localization of neutral ceramidase in caveolin-enriched light membranes of murine endothelial cells. | Sphingomyelinase (SMase) and ceramidase (CDase) activities participate in sphingomyelin (SM) metabolism and have a role in the signal transduction of a variety of ligands. In this study evidence is presented that caveolin-enriched light membranes (CELMs) of murine endothelial cells, characterized by high SM, ceramide (... |
11591163 | Fluorescence anisotropy measurements of lipid order in plasma membranes and lipid rafts from RBL-2H3 mast cells. | Specialized plasma membrane domains known as lipid rafts participate in signal transduction and other cellular processes, and their liquid ordered (L(o)) phase appears to be important for their function. To quantify ordered lipids in biological membranes, we investigated steady-state fluorescence anisotropy of two lipi... |
11591153 | The first transmembrane segment of the dopamine D2 receptor: accessibility in the binding-site crevice and position in the transmembrane bundle. | The binding site of the dopamine D2 receptor, like that of homologous G-protein-coupled receptors (GPCRs), is contained within a water-accessible crevice formed among its seven transmembrane segments (TMs). Using the substituted-cysteine-accessibility method (SCAM), we are mapping the residues that contribute to the su... |
11590657 | Novel liver macromolecular MR contrast agent with a polypropylenimine diaminobutyl dendrimer core: comparison to the vascular MR contrast agent with the polyamidoamine dendrimer core. | As MRI contrast agents, more hydrophobic molecules reportedly accumulate in the liver and thus are potentially useful as liver MRI contrast agents. In this study, a generation-4 polypropylenimine diaminobutane dendrimer (DAB-Am64), which is expected to be more hydrophobic than the generation-4 polyamidoamine dendrimer ... |
11590655 | Positive effects of polyethylene glycol conjugation to generation-4 polyamidoamine dendrimers as macromolecular MR contrast agents. | Macromolecules conjugated with polyethylene glycol (PEG) acquire more hydrophilicity, resulting in a longer half-life in circulation and lower immunogenicity. Two novel conjugates for MRI contrast agents were synthesized from a generation-4 polyamidoamine dendrimer (G4D), 2-(p-isothiocyanatobenzyl)-6-methyl-diethylenet... |
11590226 | Regulation of sterol regulatory element-binding proteins by cholesterol flux in CaCo-2 cells. | The regulation of sterol regulatory element-binding proteins (SREBP) by cholesterol flux was studied in the intestinal cell line CaCo-2. CaCo-2 cells were incubated for 18 h with micelles containing 5 mM taurocholate and 500 microM oleic acid or micelles containing either 200 microM cholesterol or 150 microM lysophosph... |
11590018 | Intramers as promising new tools in functional proteomics. | Aptamers are valuable tools for studying numerous aspects of biological processes, opening up new experimental opportunities to analyse the function of a wide range of cellular molecules. Functional RNA molecules can be rapidly selected in vitro from complex combinatorial mixtures of different sequences. Recently, it w... |
11589464 | Determination of free aspartic acid enantiomers in rat brain by capillary electrophoresis with laser-induced fluorescence detection. | Quantification of aspartic acid enantiomers in rat brain by using a chiral capillary electrophoresis procedure is described. Amino acids were pre-column derivatized with naphthalene-2,3-dialdehyde. Enantiomeric separation was achieved by micellar electrokinetic chromatography in the presence of methanol and beta-cyclod... |
11587768 | Structural insights into the mechanical regulation of molecular recognition sites. | Intriguing experimental and computational data are emerging to suggest that mechanical forces regulate the functional states of some proteins by stretching them into nonequilibrium states. Using the extracellular matrix protein fibronectin as an example, we discuss molecular design principles that might control the exp... |
11586355 | Swollen liquid-crystalline lamellar phase based on extended solid-like sheets. | Ordering particles at the nanometre length scale is a challenging and active research area in materials science. Several approaches have so far been developed, ranging from the manipulation of individual particles to the exploitation of self-assembly in colloids. Nanometre-scale ordering is well known to appear spontan... |
11585788 | Molecular detection of antimicrobial resistance. | The determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. Nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. Examples are the detection o... |
11585782 | Mycolic acid analysis by high-performance liquid chromatography for identification of Mycobacterium species. | Mycobacterium tuberculosis is the etiologic agent of tuberculosis and can be accurately detected by laboratories using commercial genetic tests. Nontuberculosis mycobacteria (NTM) causing other mycobacterioses can be difficult to identify. The identification processes are confounded by an increasing diversity of newly ... |
11583553 | Molecular recognition in cyclodextrin complexes of amino acid derivatives. 2. A new perturbation: the room-temperature crystallographic structure determination for the N-acetyl-p-methoxy-L-phenylalanine methyl ester/beta-cyclodextrin complex. | Cyclodextrins (CDs) are cyclic oligosaccharides that encapsulate various small organic molecules, forming inclusion complexes. Because CD complexes are held together purely by noncovalent interactions, they function as excellent models for the study of chiral and molecular recognition mechanisms. Recently, room-tempera... |
11583552 | Molecular recognition in cyclodextrin complexes of amino acid derivatives. 1. Crystallographic studies of beta-cyclodextrin complexes with N-acetyl-L-phenylalanine methyl ester and N-acetyl-L-phenylalanine amide pseudopeptides. | Cyclodextrins (CDs) are widely utilized in studies of chiral and molecular recognition. By changing the functionality of the guest molecule, the effect of such changes on recognition by the host CD molecule can be examined. We report crystal structure determinations for two nearly isomorphous complexes of phenylalanine... |
11583535 | Amphiphilic diblock dendrimers: synthesis and incorporation in Langmuir and Langmuir-Blodgett films. | A new dendron with peripheral long alkyl chains and containing five C(60) units in the branching shell has been prepared and attached to a Fréchet-type dendron functionalized with ethylene glycol chains. The peripheral substitution of the resulting globular dendrimer with hydrophobic chains on one hemisphere and hydrop... |
11583583 | Cloning and expression of a single-chain catalytic antibody that acts as a glutathione peroxidase mimic with high catalytic efficiency. | Glutathione peroxidase (GPX) has a powerful role in scavenging reactive oxygen species. In previous papers we have developed a new strategy for generating abzymes: the monoclonal antibody with a substrate-binding site is first prepared, then a catalytic group is incorporated into the monoclonal antibody's binding site ... |
11580236 | Self-assembly of the amphipathic helix (VHLPPP)8. A mechanism for zein protein body formation. | gamma-Zein, a maize storage protein with an N-terminal proline-rich repetitive domain (gamma-ZNPRD), is located at the periphery of protein bodies. This domain appears to be indispensable for the aggregation of the protein on the surface of the organelle. The peptide (VHLPPP)8, spanning the gamma-ZNPRD, adopts a polypr... |
11581314 | Deficiency of small GTPase Rac2 affects T cell activation. | Rac2 is a hematopoietic-specific GTPase acting as a molecular switch to mediate both transcriptional activation and cell morphological changes. We have examined the effect of Rac2 deficiency during T cell activation. In Rac2(-/-) T cells, proliferation was reduced upon stimulation with either plate-bound anti-CD3 or T ... |
11581298 | Crystal structure of the TRANCE/RANKL cytokine reveals determinants of receptor-ligand specificity. | RANK, the receptor activator of NF-kappaB, and its ligand RANKL (initially termed TRANCE, also termed ODF and OPGL), are a TNF superfamily receptor-ligand pair that govern the development and function of osteoclasts, lymphoid tissue, and mammary epithelium. While TNF family cytokines share a common structural scaffold,... |
11581287 | KIFC3, a microtubule minus end-directed motor for the apical transport of annexin XIIIb-associated Triton-insoluble membranes. | We have identified and characterized a COOH-terminal motor domain-type kinesin superfamily protein (KIFC), KIFC3, in the kidney. KIFC3 is a minus end-directed microtubule motor protein, therefore it accumulates in regions where minus ends of microtubules assemble. In polarized epithelial cells, KIFC3 is localized on me... |
11580108 | Agent-based computer simulation and sirs: building a bridge between basic science and clinical trials. | The management of Systemic Inflammatory Response Syndrome (SIRS)/Multiple Organ Failure (MOF) remains the greatest challenge in the field of critical care. There has been uniform difficulty in translating the results of basic science research into effective therapeutic regimes. We propose that this is due in part to a ... |
11578199 | Design and synthesis of porphyrins bearing rigid hydrogen bonding motifs: highly versatile building blocks for self-assembly of polymers and discrete arrays. | Two aldehydes, 2,6-diacetamido-4-formylpyridine (7) and 1-butyl-6-formyluracil (11), are used to synthesize five pyridyl and four uracyl meso-subsituted porphyrins. With these complementary porphyrin building blocks, it is possible to build various types of multi-porphyrin supramolecules with different spatial relation... |
11578932 | Surface plasmon resonance: towards an understanding of the mechanisms of biological molecular recognition. | With the introduction of new instruments and improved sensor chip chemistries, surface plasmon resonance (SPR) is finding new applications for molecular interaction studies. Easy access to high-quality kinetic and thermodynamic data for macromolecular binding events is providing insights into the fundamental mechanisms... |
11578637 | The dimeric complex of cyclomaltoheptaose with 1,14-tetradecanedioic acid. Comparison with related complexes. | The structure of the complex of cyclomaltoheptaose (beta-cyclodextrin, betaCD) with 1,14-tetradecanedioic acid has been determined and refined to a final R=0.0693 based on 9824 observed reflections. Each diacid molecule threads through two betaCD monomers arranged in dimers thus, forming a [3]pseudorotaxane. The end ca... |
11576696 | Transcytosis of nanoparticle and dendrimer delivery systems: evolving vistas. | The translocation of particulate matter across the gastrointestinal tract is now a well documented phenomenon offering new potential for the delivery of drugs with poor dissolution profiles and labile chemistries via encapsulation in biodegradable nanoparticles. The last few years have seen an acceleration in the numbe... |
11574036 | Self-association of facially amphiphilic methylene bridged glycoluril dimers. | [structure: see text] Facially amphiphilic derivatives of methylene bridged glycoluril dimers are a versatile model system for systematic studies of self-assembly in water. Thorough physical organic characterization, including analytical ultracentrifugation, a technique rarely used in synthetic self-assembly studies, a... |
11574015 | Metal-directed formation of three-dimensional M(3)L(2) trigonal-bipyramidal cages. | [reaction: see text] The simple combination of two angular tritopic pyridine donor linkers (109 degrees bond angle) with three ditopic platinum acceptors (90 degrees bond angle) leads to essentially quantitative formation of self-assembled M(3)L(2) trigonal-bipyramidal (TBP) supramolecular species. |
11574012 | Effect of terminal group sterics and dendron packing on chirality transfer from the central core of a dendrimer. | [structure: see text] The conformational properties of intramolecularly hydrogen-bonded dendrimers constructed from (S)-1,1'-bi-2-naphthol as a chiral central core are described. Circular dichroism studies revealed that chirality transfer to the periphery occurs only when sterically demanding terminal esters are employ... |
11573998 | A dendritic active site: catalysis of the Henry reaction. | [reaction: see text] Dendrimers containing an encapsulated tertiary amine were prepared by coupling tris(2-aminoethyl)amine with dendritic branches derived from L-lysine. These dendrimers were used as catalysts in the Henry (nitroaldol) reaction between 4-nitrobenzaldehyde and nitroethane, and their catalytic performan... |
11574693 | Sugar additives for MALDI matrices improve signal allowing the smallest nucleotide change (A:T) in a DNA sequence to be resolved. | Sample preparation for matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) of DNA is critical for obtaining high quality mass spectra. Sample impurity, solvent content, substrate surface and environmental conditions (temperature and humidity) all affect the rate of matrix-analyte co-crystallizati... |
11574689 | New chemically reactive dsDNAs containing single internucleotide monophosphoryldithio links: reactivity of 5'-mercapto-oligodeoxyribonucleotides. | Novel modified DNA duplexes with single bridging 5'-SS-monophosphoryldithio links [-OP(=O)-O(-)-SS-CH(2)-] were synthesized by autoligation of an oligonucleotide 3'-phosphorothioate and a 5'-mercapto-oligonucleotide previously converted to a 2-pyridyldisulfide adduct. Monophosphoryldisulfide link formation is not a str... |
11574677 | Protein and DNA requirements of the bacteriophage HP1 recombination system: a model for intasome formation. | A fundamental step in site-specific recombination reactions involves the formation of properly arranged protein-DNA structures termed intasomes. The contributions of various proteins and DNA binding sites in the intasome determine not only whether recombination can occur, but also in which direction the reaction is lik... |
11574464 | IL-17s adopt a cystine knot fold: structure and activity of a novel cytokine, IL-17F, and implications for receptor binding. | The proinflammatory cytokine interleukin 17 (IL-17) is the founding member of a family of secreted proteins that elicit potent cellular responses. We report a novel human IL-17 homolog, IL-17F, and show that it is expressed by activated T cells, can stimulate production of other cytokines such as IL-6, IL-8 and granulo... |
11574463 | Crystal structure of human protein kinase CK2: insights into basic properties of the CK2 holoenzyme. | The crystal structure of a fully active form of human protein kinase CK2 (casein kinase 2) consisting of two C-terminally truncated catalytic and two regulatory subunits has been determined at 3.1 A resolution. In the CK2 complex the regulatory subunits form a stable dimer linking the two catalytic subunits, which make... |
11572685 | Self-assembly with postmodification: kinetically stabilized metalla-supramolecular rectangles. | Interaction of a predesigned molecular "clip" (4) with rigid dipyridyl bridging ligands, in acetone/water mixtures, leads to the formation of molecular rectangles (5-8) in 92-97% isolated yields via spontaneous self-assembly. Characterization was accomplished with multinuclear NMR and UV-vis spectroscopy, FAB mass spec... |
11570893 | Thermodynamic stability of the bacteriorhodopsin lattice as measured by lipid dilution. | To determine the strength of noncovalent interactions that stabilize a membrane protein complex, we have developed an in vitro method for quantifying the dissociation of the bacteriorhodopsin (BR) lattice, a naturally occurring two-dimensional crystal. A lattice suspension was titrated with a short- and long-chain phos... |
11571194 | New additive for culture media for rapid identification of aflatoxin-producing Aspergillus strains. | A new reliable, fast, and simple method for the detection of aflatoxigenic Aspergillus strains, consisting of the addition of a cyclodextrin (a methylated beta-cyclodextrin derivative) to common media used for testing mycotoxin production ability, was developed. We propose the use of this compound as an additive for fu... |
11567099 | The roles of turn formation and cross-strand interactions in fibrillization of peptides derived from the OspA single-layer beta-sheet. | We previously demonstrated that a beta-hairpin peptide, termed BH(9-10), derived from a single-layer beta-sheet of Borrelia OspA protein, formed a native-like beta-turn in trifluoroethanol (TFE) solution, and it assembled into amyloid-like fibrils at higher TFE concentrations. This peptide is highly charged, and fibril... |
11567097 | The role of a beta-bulge in the folding of the beta-hairpin structure in ubiquitin. | It is known that the peptide corresponding to the N-terminal beta-hairpin of ubiquitin, U(1-17), can populate the monomeric beta-hairpin conformation in aqueous solution. In this study, we show that the Gly-10 that forms the bulge of the beta-turn in this hairpin is very important to the stability of the hairpin. The d... |
11567000 | Recombination in the ompA gene but not the omcB gene of Chlamydia contributes to serovar-specific differences in tissue tropism, immune surveillance, and persistence of the organism. | Sequences of the major outer membrane protein (MOMP) gene (ompA) and the outer membrane complex B protein gene (omcB) from Chlamydia trachomatis, Chlamydia pneumoniae, and Chlamydia psittaci were analyzed for evidence of intragenic recombination and for linkage equilibrium. The Sawyer runs test, compatibility matrices,... |
11566978 | Role of Agrobacterium VirB11 ATPase in T-pilus assembly and substrate selection. | The VirB11 ATPase is a subunit of the Agrobacterium tumefaciens transfer DNA (T-DNA) transfer system, a type IV secretion pathway required for delivery of T-DNA and effector proteins to plant cells during infection. In this study, we examined the effects of virB11 mutations on VirB protein accumulation, T-pilus product... |
11566811 | Bilayers of nucleosome core particles. | Among the multiple effects involved in chromatin condensation and decondensation processes, interactions between nucleosome core particles are suspected to play a crucial role. We analyze them in the absence of linker DNA and added proteins, after the self-assembly of isolated nucleosome core particles under controlled... |
11566796 | Use of cyclodextrins to monitor transbilayer movement and differential lipid affinities of cholesterol. | In view of the demonstrated cholesterol-binding capabilities of certain cyclodextrins, we have examined whether these agents can also catalyze efficient transfer of cholesterol between lipid vesicles. We here demonstrate that beta- and gamma-cyclodextrins can dramatically accelerate the rate of cholesterol transfer bet... |
11566795 | Membrane insertion and orientation of polyalanine peptides: a (15)N solid-state NMR spectroscopy investigation. | Polyalanine-based peptides were prepared by solid-phase peptide synthesis, labeled with (15)N at selected sites, reconstituted into oriented phosphatidylcholine bilayers, and investigated by proton-decoupled (15)N solid-state NMR spectroscopy. The anisotropic (15)N chemical shift is a direct indicator of helix alignmen... |
11566791 | Orientation and dynamics of an antimicrobial peptide in the lipid bilayer by solid-state NMR spectroscopy. | The orientation and dynamics of an 18-residue antimicrobial peptide, ovispirin, has been investigated using solid-state NMR spectroscopy. Ovispirin is a cathelicidin-like model peptide (NH(2)-KNLRRIIRKIIHIIKKYG-COOH) with potent, broad-spectrum bactericidal activity. (15)N NMR spectra of oriented ovispirin reconstitute... |
11566789 | Binding of cross-linked glycosylphosphatidylinositol-anchored proteins to discrete actin-associated sites and cholesterol-dependent domains. | The mechanism by which cross-linked glycosylphosphatidylinositol (GPI)-anchored proteins are immobilized has been a mystery because both the binding to a transmembrane protein and attachment to a rigid cytoskeleton are needed. Using laser tweezers surface scanning resistance (SSR) technology, we obtained physical evide... |
11566784 | Characterization of mixed monolayers of phosphatidylcholine and a dicationic gemini surfactant SS-1 with a langmuir balance: effects of DNA. | Monolayers of a cationic gemini surfactant, 2,3-dimethoxy-1,4-bis(N-hexadecyl-N;N-dimethyl-ammonium)butane dibromide (abbreviated as SS-1) and its mixtures with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) were studied using a Langmuir balance. More specifically, we measured the force-area (pi-A) curves and ... |
11566772 | A new dimension in retrograde flow: centripetal movement of engulfed particles. | Centripetal motion of surface-adherent particles is a classic experimental system for studying surface dynamics on a eukaryotic cell. To investigate bead migration over the entire cell surface, we have developed an experimental assay using multinuclear giant fibroblasts, which provide expanded length scales and an unam... |
11566770 | Analytic binding isotherms describing competitive interactions of a protein ligand with specific and nonspecific sites on the same DNA oligomer. | Many studies of specific protein-nucleic acid binding use short oligonucleotides or restriction fragments, in part to minimize the potential for nonspecific binding of the protein. However, when the specificity ratio is low, multiple nonspecifically bound proteins may occupy the region of DNA corresponding to one speci... |
11566759 | Calculations of free-energy contributions to protein-RNA complex stabilization. | The problem of calculating binding affinities of protein-RNA complexes is addressed by analyzing a computational strategy of modeling electrostatic free energies based on a nonlinear Poisson-Boltzmann (NLPB) model and linear response approximation (LRA). The underlying idea is to treat binding as a two-step process. So... |
11564885 | Perinatal lethality and endothelial cell abnormalities in several vessel compartments of fibulin-1-deficient mice. | The extracellular matrix protein fibulin-1 is a distinct component of vessel walls and can be associated with other ligands present in basement membranes, microfibrils, and elastic fibers. Its biological role was investigated by the targeted inactivation of the fibulin-1 gene in mice. This led to massive hemorrhages in... |
11564552 | Improved oral bioavailability of artemisinin through inclusion complexation with beta- and gamma-cyclodextrins. | The bioavailability of beta- and gamma-cyclodextrin artemisinin complexes was evaluated in comparison with a normal commercially available preparation, Artemisinin 250. Twelve healthy male volunteers participated in the study conducted according to a three-way crossover design. The bioavailability was compared using th... |
11563980 | FYVE zinc-finger proteins in the plant model Arabidopsis thaliana: identification of PtdIns3P-binding residues by comparison of classic and variant FYVE domains. | Classic FYVE zinc-finger domains recognize the phosphoinositide signal PtdIns3P and share the basic (R/K)(1)(R/K)HHCR(6) (single-letter amino acid codes) consensus sequence. This domain is present in predicted PtdIns3P 5-kinases and lipases from Arabidopsis thaliana. Other Arabidopsis proteins, named PRAF, consist of a... |
11562535 | Definition of neutralizing sites on African horse sickness virus serotype 4 VP2 at the level of peptides. | The antigenic structure of African horse sickness virus (AHSV) serotype 4 capsid protein VP2 has been determined at the peptide level by PEPSCAN analysis in combination with a large collection of polyclonal antisera and monoclonal antibodies. VP2, the determinant for the virus serotype and an important target in virus ... |
11559827 | Correspondence of the functional epitopes of poxvirus and human interleukin-18-binding proteins. | Molluscum contagiosum virus, a human poxvirus that causes persistent small benign skin tumors, encodes a variety of putative immune defense proteins. Three such proteins, MC51L, MC53L, and MC54L, have 20 to 35% amino acid sequence identities with human interleukin-18 (hIL-18)-binding protein (hIL-18BP), a naturally occ... |
11559825 | Cellular membrane-binding ability of the C-terminal cytoplasmic domain of human immunodeficiency virus type 1 envelope transmembrane protein gp41. | The amphipathic alpha-helices located in the cytoplasmic tail of the envelope (Env) transmembrane glycoprotein gp41 of human immunodeficiency virus type 1 have been implicated in membrane association and cytopathicity. Deletion of the last 12 amino acids in the C terminus of this domain severely impairs infectivity. Ho... |
11559800 | Cocirculation of avian H9N2 and contemporary "human" H3N2 influenza A viruses in pigs in southeastern China: potential for genetic reassortment? | Pigs are permissive to both human and avian influenza viruses and have been proposed to be an intermediate host for the genesis of pandemic influenza viruses through reassortment or adaptation of avian viruses. Prospective virological surveillance carried out between March 1998 and June 2000 in Hong Kong, Special Admin... |
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