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14581529 | Oct-1 is posttranslationally modified and exhibits reduced capacity to bind cognate sites at late times after infection with herpes simplex virus 1. | In herpes simplex virus 1-infected cells, a high level of alpha gene expression requires the transactivation of the genes by a complex containing the viral alpha transinducing factor (alphaTIF) and two cellular proteins. The latter two, HCF-1 and octamer binding protein Oct-1, are transcriptional factors regulated in a... |
14581526 | Atomic force microscopy investigation of human immunodeficiency virus (HIV) and HIV-infected lymphocytes. | Isolated human immunodeficiency virus (HIV) and HIV-infected human lymphocytes in culture have been imaged for the first time by atomic force microscopy (AFM). Purified virus particles spread on glass substrates are roughly spherical, reasonably uniform, though pleomorphic in appearance, and have diameters of about 120... |
14581225 | Predissociated dimers and molten globule monomers in the equilibrium unfolding of yeast glutathione reductase. | The equilibrium unfolding of dimeric yeast glutathione reductase (GR) by guanidine hydrochloride (GdnHCl) was investigated. Unfolding was monitored by a variety of techniques, including intrinsic fluorescence emission, anisotropy and iodide quenching measurements, far-ultraviolet circular dichroism and thiol reactivity... |
14581222 | Modeling the binding sites of anti-hen egg white lysozyme antibodies HyHEL-8 and HyHEL-26: an insight into the molecular basis of antibody cross-reactivity and specificity. | Three antibodies, HyHEL-8 (HH8), HyHEL-10 (HH10), and HyHEL-26 (HH26) are specific for the same epitope on hen egg white lysozyme (HEL), and share >90% sequence homology. Their affinities vary by several orders of magnitude, and among the three antibodies, HH8 is the most cross-reactive with kinetics of binding that ar... |
14581218 | Role of backbone hydration and salt-bridge formation in stability of alpha-helix in solution. | We test molecular level hypotheses for the high thermal stability of alpha-helical conformations of alanine-based peptides by performing detailed atomistic simulations of a 20-amino-acid peptide with explicit treatment of water. To assess the contribution of large side chains to alpha-helix stability through backbone d... |
14581217 | Exciton theory for supramolecular chlorosomal aggregates: 1. Aggregate size dependence of the linear spectra. | The interior of chlorosomes of green bacteria forms an unusual antenna system organized without proteins. The steady-spectra (absorption, circular dichroism, and linear dichroism) have been modeled using the Frenkel Hamiltonian for the large tubular aggregates of bacteriochlorophylls with geometries corresponding to th... |
14581216 | Photo-oxidation of P740, the primary electron donor in photosystem I from Acaryochloris marina. | Fourier transform infrared spectroscopy (FTIR) difference spectroscopy in combination with deuterium exchange experiments has been used to study the photo-oxidation of P740, the primary electron donor in photosystem I from Acaryochloris marina. Comparison of (P740(+)-P740) and (P700(+)-P700) FTIR difference spectra sho... |
14581208 | Separation of liquid phases in giant vesicles of ternary mixtures of phospholipids and cholesterol. | We use fluorescence microscopy to directly observe liquid phases in giant unilamellar vesicles. We find that a long list of ternary mixtures of high melting temperature (saturated) lipids, low melting temperature (usually unsaturated) lipids, and cholesterol produce liquid domains. For one model mixture in particular, ... |
14581201 | Thermodynamics of heat activation of single capsaicin ion channels VR1. | Temperature affects functions of all ion channels, but few of them can be gated directly. The vanilloid receptor VR1 provides one exception. As a pain receptor, it is activated by heat >42 degrees C in addition to other noxious stimuli, e.g. acids and vanilloids. Although it is understood how ligand- and voltage-gated ... |
14581196 | A mesoscopic model for protein-protein interactions in solution. | Protein self-association may be detrimental in biological systems, but can be utilized in a controlled fashion for protein crystallization. It is hence of considerable interest to understand how factors like solution conditions prevent or promote aggregation. Here we present a computational model describing interaction... |
14579354 | Atomic contact vectors in protein-protein recognition. | The ability to analyze and compare protein-protein interactions on the structural level is critical to our understanding of various aspects of molecular recognition and the functional interplay of components of biochemical networks. In this study, we introduce atomic contact vectors (ACVs) as an intuitive way to repres... |
14578428 | Differential distribution of harmonin isoforms and their possible role in Usher-1 protein complexes in mammalian photoreceptor cells. | <h4>Purpose</h4>Human Usher syndrome is the most common form of combined deafness and blindness. Usher type I (USH1), the most severe form, is characterized by profound congenital deafness, constant vestibular dysfunction, and prepubertal onset retinitis pigmentosa. Previous studies have shown that the USH1-proteins my... |
14577770 | Topological evolution in uranyl dicarboxylates: synthesis and structures of one-dimensional UO2(C6H8O4)(H2O)2 and three-dimensional UO2(C6H8O4). | Two novel uranyl adipates are reported as synthesized via hydrothermal treatment of uranium oxynitrate and adipic acid. One-dimensional UO(2)(C(6)H(8)O(4))(H(2)O)(2) (1) [a = 9.6306(6) A, c = 11.8125(10) A, tetragonal, P4(3)2(1)2 (No. 96), Z = 4] consists of chains of (UO(2))O(4)(H(2)O)(2) hexagonal bipyramids tethered... |
14578855 | Membrane cholesterol but not putative receptors mediates anandamide-induced hepatocyte apoptosis. | The endogenous cannabinoid anandamide, a lipid mediator, induces various physiologic events such as vascular relaxation, inhibition of gap-junctions formation, tumor proliferation, neurologic analgesia, and apoptosis. Although increased concentration of anandamide in plasma has been implicated in pathophysiologic state... |
14576310 | Groove-binding unsymmetrical cyanine dyes for staining of DNA: syntheses and characterization of the DNA-binding. | Two new crescent-shaped unsymmetrical cyanine dyes have been synthesised and their interactions with DNA have been investigated by different spectroscopic methods. These dyes are analogues to a minor groove binding unsymmetrical cyanine dye, BEBO, recently reported by us. In this dye, the structure of the known interca... |
14576305 | Energetics of echinomycin binding to DNA. | Differential scanning calorimetry and UV thermal denaturation have been used to determine a complete thermodynamic profile for the bis-intercalative interaction of the peptide antibiotic echinomycin with DNA. The new calorimetric data are consistent with all previously published binding data, and afford the most rigoro... |
14576294 | Diversity of type II restriction endonucleases that require two DNA recognition sites. | Orthodox Type IIP restriction endonucleases, which are commonly used in molecular biological work, recognize a single palindromic DNA recognition sequence and cleave within or near this sequence. Several new studies have reported on structural and biochemical peculiarities of restriction endonucleases that differ from ... |
14576293 | Therapeutic modulation of endogenous gene function by agents with designed DNA-sequence specificities. | Designer molecules that can specifically target pre-determined DNA sequences provide a means to modulate endogenous gene function. Different classes of sequence-specific DNA-binding agents have been developed, including triplex-forming molecules, synthetic polyamides and designer zinc finger proteins. These different t... |
12894217 | CD95 ligand--death factor and costimulatory molecule? | The CD95 ligand is involved as a death factor in the regulation of activation-induced cell death, establishment of immune privilege and tumor cell survival. In addition, CD95L may serve as a costimulatory molecule for T-cell activation. Alterations in expression or shedding of membrane and soluble CD95L are associated ... |
14576101 | Pharmacology of novel heteroaromatic polycycle antibacterials. | Heteroaromatic polycycle (HARP) compounds are a novel class of small (M(w), 600 to 650) DNA-binding antibacterials. HARP compounds exhibit a novel mechanism of action by preferentially binding to AT-rich sites commonly found in bacterial promoters and replication origins. Noncovalent binding in the minor groove of DNA ... |
14576097 | CesRK, a two-component signal transduction system in Listeria monocytogenes, responds to the presence of cell wall-acting antibiotics and affects beta-lactam resistance. | Listeria monocytogenes is a food-borne pathogen that can cause a variety of illnesses ranging from gastroenteritis to life-threatening septicemia. The beta-lactam antibiotic ampicillin remains the drug of choice for the treatment of listeriosis. We have previously identified a response regulator of a putative two-compo... |
14573866 | Modulating the binding properties of an anti-17beta-estradiol antibody by systematic mutation combinations. | The anti-17beta-estradiol antibody 57-2 has been a subject for several protein engineering studies that have produced a number of mutants with improved binding properties. Here, we generated a set of 16 antibody 57-2 variants by systematically combining mutations previously identified from phage display-derived improve... |
14573860 | Self-assembly of single integral membrane proteins into soluble nanoscale phospholipid bilayers. | One of the biggest challenges in pharmaceutical research is obtaining integral membrane proteins in a functional, solubilized, and monodisperse state that provides a native-like environment that maintains the spectrum of in vivo activities. Many of these integral membrane proteins are receptors, enzymes, or other macro... |
14573858 | The geometry and efficacy of cation-pi interactions in a diagonal position of a designed beta-hairpin. | Cation-pi interactions are common in proteins, but their contribution to the stability and specificity of protein structure has not been well established. In this study, we examined the impact of cation-pi interactions in a diagonal position of a beta-hairpin peptide through comparison of the interaction of Phe or Trp ... |
14573803 | Cholesterol-dependent infection of Burkitt's lymphoma cell lines by Epstein-Barr virus. | Epstein-Barr virus (EBV) infection is a multi-step process, first requiring virus binding to the host cell, followed by fusion of the viral envelope with the host cell plasma membrane. Efficient EBV entry into B cells requires, at the minimum, the interaction of the EBV-encoded glycoproteins gp350 with cellular CD21 an... |
14573673 | Growth phase-dependent response of Helicobacter pylori to iron starvation. | Iron is an essential nutrient that is often found in extremely limited available quantities within eukaryotic hosts. Because of this, many pathogenic bacteria have developed regulated networks of genes important for iron uptake and storage. In addition, it has been shown that many bacteria use available iron concentrat... |
14571454 | Peripheral nerve fascicles: anatomy and clinical relevance. | Within a peripheral nerve, the individual nerve fibers are grouped together in fascicles. Whether there is somatotopic organization within these fascicles has long been of interest, the subject of many investigations, and somewhat controversial. Evidence from diverse sources now points to important somatotopic clusteri... |
12940771 | Regulation and organization of adenylyl cyclases and cAMP. | Adenylyl cyclases are a critically important family of multiply regulated signalling molecules. Their susceptibility to many modes of regulation allows them to integrate the activities of a variety of signalling pathways. However, this property brings with it the problem of imparting specificity and discrimination. Rec... |
12868961 | Mechanism of horseradish peroxidase inactivation by benzhydrazide: a critical evaluation of arylhydrazides as peroxidase inhibitors. | Many compounds are oxidized by haem enzymes, such as peroxidases and cytochromes P450, to highly reactive intermediates that function as enzyme inactivators. To evaluate the potential of arylhydrazides as selective metabolically activated peroxidase inhibitors, the mechanism of HRPC (horseradish peroxidase isoenzyme C)... |
14569161 | [Lipid rafts and their analytical methods]. | Microdomains in cell membranes consist of caveolae and lipid rafts, in which cholesterol, glycolipids, and sphingomyelin are concentrated. While caveolae are relatively stable because caveolin, an integral protein, supports the structure, lipid rafts are unstable, being dynamically produced and degraded. In lipid rafts... |
14568521 | PFG-assisted selection and suppression of 1H NMR signals in the solid state under fast MAS. | Under fast MAS conditions, techniques for 1H signal selection and suppression, which have originally been developed for solution-state NMR, become applicable to solids. In this work, we describe how WATERGATE and DANTE pulse sequences can be used under MAS to selectively excite or suppress peaks in 1H solid-state spect... |
14568924 | Thymocyte sensitivity and supramolecular activation cluster formation are developmentally regulated: a partial role for sialylation. | TCR reactivity is tuned during thymic development. Immature thymocytes respond to low-affinity self-ligands resulting in positive selection. Following differentiation, T cells no longer respond to low-affinity ligands, but respond well to high-affinity (foreign) ligands. We show in this study that this response include... |
14568709 | Patterning of photosensitive polyimide LB film and its application in the fabrication of biomolecular microphotodiode array. | Ultra thin film of photosensitive polyimide having benzene and sulfonyloxyimide moieties in the main chain was prepared using a Langmuir-Blodgett (LB) technique, and then micro array pattern of the polyimide LB film on a gold substrate was obtained by deep UV lithographic technique. In order to array cytochrome c molec... |
14566013 | Perlecan and tumor angiogenesis. | Perlecan is a major heparan sulfate proteoglycan (HSPG) of basement membranes (BMs) and connective tissues. The core protein of perlecan is divided into five domains based on sequence homology to other known proteins. Commonly, the N-terminal domain I of mammalian perlecan is substituted with three HS chains that can b... |
14566804 | Novel complexation hydrogels for oral peptide delivery: in vitro evaluation of their cytocompatibility and insulin-transport enhancing effects using Caco-2 cell monolayers. | Poly[methacrylic acid-grafted-poly(ethylene glycol)] [P(MAA-g-EG)] is a complexation hydrogel molecularly designed for oral peptide delivery. In this work, the cytotoxicity and insulin-transport enhancing effect of P(MAA-g-EG) microparticles on intestinal epithelial cells were evaluated using Caco-2 cell monolayers. A ... |
14563870 | Recognition of DNA by three ferric uptake regulator (Fur) homologs in Bacillus subtilis. | Bacillus subtilis contains three Fur homologs: Fur, PerR, and Zur. Despite significant sequence similarities, they respond to different stimuli and regulate different sets of genes. DNA target site comparisons indicate that all three paralogs recognize operators with a core 7-1-7 inverted repeat. The corresponding cons... |
14563479 | Novel roles for palmitoylation of Ras in IL-1 beta-induced nitric oxide release and caspase 3 activation in insulin-secreting beta cells. | We recently demonstrated that functional inactivation of H-Ras results in significant reduction in interleukin 1 beta (IL-1 beta)-mediated effects on isolated beta cells. Since palmitoylation of Ras has been implicated in its membrane targeting, we examined the contributory roles of palmitoylation of Ras in IL-1 beta-i... |
14561885 | Visualization of membrane RNAs. | Using fluorescence microscopy, we show that previously isolated membrane-binding RNAs coat artificial phospholipid membranes relatively uniformly, except for a frequent tendency to concentrate at bends, membrane junctions, and other unusual sites. Membrane RNAs can also be visualized as single molecules or isolated com... |
14560105 | The clinical value of procalcitonin and neopterin in predicting sepsis and organ failure after major trauma. | We examined whether procalcitonin (PCT) or neopterin (NT) are useful in predicting sepsis, multiple organ failure (MOF), or death after multiple trauma (MT). In a prospective clinical study, a total of 137 consecutive trauma patients (mean age 39 years, median injury severity score [ISS] 27 points) and 34 healthy volun... |
14560035 | BARD1 participates with BRCA1 in homology-directed repair of chromosome breaks. | The BRCA1 tumor suppressor has been implicated in the maintenance of chromosomal stability through homology-directed repair of DNA double-strand breaks. Much of the BRCA1 in cells forms a heterodimeric complex with a structurally related protein BARD1. We report that expression of truncated mouse or human BARD1 peptide... |
14560007 | Quantitative analysis of CBP- and P300-induced histone acetylations in vivo using native chromatin. | In vivo, histone tails are involved in numerous interactions, including those with DNA, adjacent histones, and other, nonhistone proteins. The amino termini are also the substrates for a number of enzymes, including histone acetyltransferases (HATs), histone deacetylases, and histone methyltransferases. Traditional bio... |
14559397 | Cyclodextrins and emulsions. | This paper synthesises the literature on interactions between cyclodextrins (CD) and fatty acids and glycerides, and explains how these interactions allow the use of cyclodextrins to stabilise emulsions. An example of formulation with cyclodextrins is given which discusses the preparation of simple o/w emulsions, the a... |
14559391 | In vitro release behavior and stability of insulin in complexation hydrogels as oral drug delivery carriers. | Novel pH-responsive complexation hydrogels containing pendent glucose (P(MAA-co-MEG)) or grafted PEG chains (P(MAA-g-EG)) were synthesized by photopolymerization. The feasibility of these hydrogels as oral protein delivery carriers was evaluated. The pH-responsive release behavior of insulin was analyzed from both P(MA... |
14557667 | The hepatitis B virus polymerase mutation rtV173L is selected during lamivudine therapy and enhances viral replication in vitro. | Therapy of chronic hepatitis B virus (HBV) infection with the polymerase inhibitor lamivudine frequently is associated with the emergence of viral resistance. Genotypic changes in the YMDD motif (reverse transcriptase [rt] mutations rtM204V/I) conferred resistance to lamivudine as well as reducing the in vitro replicat... |
14557661 | Metaphase chromosome tethering is necessary for the DNA synthesis and maintenance of oriP plasmids but is insufficient for transcription activation by Epstein-Barr nuclear antigen 1. | Epstein-Barr Virus (EBV) infects resting B cells, within which it establishes latency as a stable, circular episome with only two EBV components, the cis element oriP and the latently expressed protein EBNA1. It is believed that EBNA1's ability to tether oriP episomes to metaphase chromosomes is required for its stable... |
14557651 | Murine leukemia virus particle assembly quantitated by fluorescence microscopy: role of Gag-Gag interactions and membrane association. | In order to track the assembly of murine leukemia virus (MLV), we used fluorescence microscopy to visualize particles containing Gag molecules fused to fluorescent proteins (FPs). Gag-FP chimeras budded from cells to produce fluorescent spots, which passed through the same pore-size filters and sedimented at the same v... |
14557634 | Formation of polyomavirus-like particles with different VP1 molecules that bind the urokinase plasminogen activator receptor. | Icosahedral virus-like particles formed by the self-assembly of polyomavirus capsid proteins (Py-VLPs) can serve as useful nanostructures for delivering nucleic acids, proteins, and pharmaceuticals into animal cells and tissues. Four predominant surface-exposed loops in the VP1 structure offer potential sites to displa... |
14557625 | The human immunodeficiency virus type 1 Vif protein reduces intracellular expression and inhibits packaging of APOBEC3G (CEM15), a cellular inhibitor of virus infectivity. | Replication of human immunodeficiency virus type 1 (HIV-1) in most primary cells and some immortalized T-cell lines depends on the activity of the viral infectivity factor (Vif). Vif has the ability to counteract a cellular inhibitor, recently identified as CEM15, that blocks infectivity of Vif-defective HIV-1 variants... |
14557619 | Measles virus (MV) nucleoprotein binds to a novel cell surface receptor distinct from FcgammaRII via its C-terminal domain: role in MV-induced immunosuppression. | During acute measles virus (MV) infection, an efficient immune response occurs, followed by a transient but profound immunosuppression. MV nucleoprotein (MV-N) has been reported to induce both cellular and humoral immune responses and paradoxically to account for immunosuppression. Thus far, this latter activity has be... |
14556212 | G-quartet self-assembly under osmotic pressure: remote control by vesicle shrinking rather than stress. | Does osmotic pressure stimulate assembly or disassembly of supramolecules in vesicles? Self-assembly was conceivable as intravesicular response to osmotic shrinking upon application of extravesicular overpressure, whereas disassembly was conceivable as a response to bilayer stress in hyperosmotic vesicles. Self-assembl... |
14552763 | Low molecular mass peptide dendrimers that express antimicrobial properties. | A series of low-generation dendrimeric peptides was synthesized in an attempt to evaluate their antimicrobial potency. All tested dendrimeric peptides in which lysine was a starting and branching element expressed moderate activity against Staphylococcus aureus NCTC 4163, and Escherichia coli NCTC 8196. |
14531896 | Obligatory intracellular parasitism by Ehrlichia chaffeensis and Anaplasma phagocytophilum involves caveolae and glycosylphosphatidylinositol-anchored proteins. | Obligatory intracellular, human ehrlichiosis agents Ehrlichia chaffeensis and Anaplasma phagocytophilum create unique replicative compartments devoid of lysosomal markers in monocytes/macrophages and granulocytes respectively. The entry of these bacteria requires host phospholipase C (PLC)-gamma2 and protein tyrosine k... |
14532155 | Cartilage morphogenetic proteins: role in joint development, homoeostasis, and regeneration. | <h4>Background</h4>Articular cartilage homoeostasis is critical for joint function. The steady state homoeostasis of articular cartilage is a balance between anabolic morphogens such as cartilage derived morphogenetic proteins (CDMPs) and bone morphogenetic proteins (BMPs) of the BMP family and catabolic cytokines such... |
14529506 | Extending chemoselective ligation to sugar chemistry: convergent assembly of bioactive neoglycoconjugates. | Glycoproteins and glycolipids play central roles in human health and disease, and their mimetics are primary candidates for drug development. Our understanding of the molecular level of phenomena based on molecular recognition of oligosaccharides by specific receptors has taken tremendous advantage from their chemical ... |
14517945 | Molecular pathology of NEU1 gene in sialidosis. | Lysosomal sialidase (EC 3.2.1.18) has a dual physiological function; it participates in intralysosomal catabolism of sialylated glycoconjugates and is involved in cellular immune response. Mutations in the sialidase gene NEU1, located on chromosome 6p21.3, result in autosomal recessive disorder, sialidosis, which is ch... |
14515238 | Disrupted myelin and axon loss in the anterior commissure of the aged rhesus monkey. | This study assesses the effects of age on the composition of the anterior commissure of the rhesus monkey. The anterior commissures of nine young (5-10 years), five middle-aged (15-20 years), and eight old (25-35 years) monkeys were examined by light and electron microscopy. In all, 90-95% of the nerve fibers in the an... |
12968286 | Comparison of theoretical and experimental data to evaluate substrate diffusional limitations for crown ether- and methyl-beta-cyclodextrin-activated serine protease subtilisin Carlsberg in tetrahydrofuran. | Simple co-lyophilization of serine protease subtilisin Carlsberg with [12]-crown ether-4 (12-crown-4) or methyl-beta-cyclodextrin (MbetaCD) drastically increases its catalytic activity in organic solvents. We investigated whether the improved activity would cause substrate diffusional limitations. To experimentally ass... |
12895563 | Studies on adsorption of dyes on beta-cyclodextrin polymer. | Beta-cyclodextrin (beta-CD) polymers are used for the removal of various dyes from aqueous solutions. Three insoluble polymers with different degrees of beta-CD were used. Results of adsorption experiments showed that these polymers exhibited high sorption capacities toward dyes. The mechanism of adsorption was both ph... |
15035043 | The versatile bacterial type IV secretion systems. | Bacteria use type IV secretion systems for two fundamental objectives related to pathogenesis--genetic exchange and the delivery of effector molecules to eukaryotic target cells. Whereas gene acquisition is an important adaptive mechanism that enables pathogens to cope with a changing environment during invasion of the... |
14992002 | [Studies on formulations of Panax notoginsenosides for intranasal administration]. | <h4>Aim</h4>To develop high bioavailability preparations without irritation for Panax notoginsenosides.<h4>Methods</h4>The effects of some additives such as microcrystalline cellulose, beta-cyclodextrin and hydroxypropyl cellulose on drug in the preparations were examined.<h4>Results</h4>Saponins of Panax notoginseng (... |
14971307 | Study of glimepiride-b-cyclodextrin complex. | The interaction of glimepiride with b-cyclodextrin (b-CD) has been studied by several analytical techniques, including 1H NMR, infrared spectroscopy (FTIR), powder x-ray diffractometry (XRD), thermal analysis (DSC) and scanning electron microscopy (SEM). The existence of an inclusion complex was proved in solution by p... |
14595119 | The cyclase-associated protein CAP as regulator of cell polarity and cAMP signaling in Dictyostelium. | Cyclase-associated protein (CAP) is an evolutionarily conserved regulator of the G-actin/F-actin ratio and, in yeast, is involved in regulating the adenylyl cyclase activity. We show that cell polarization, F-actin organization, and phototaxis are altered in a Dictyostelium CAP knockout mutant. Furthermore, in compleme... |
14595023 | De novo designed cyclic-peptide heme complexes. | The structural characterization of de novo designed metalloproteins together with determination of chemical reactivity can provide a detailed understanding of the relationship between protein structure and functional properties. Toward this goal, we have prepared a series of cyclic peptides that bind to water-soluble m... |
14593087 | Distinct molecular recognition of psychostimulants by human and Drosophila serotonin transporters. | In this study, human embryonic kidney (HEK)-293 cells stably expressing human, Drosophila, or a chimeric serotonin (5-hydroxytryptamine, 5-HT) transporter (hSERT, dSERT, and H(1-281)D(282-476)H(477-638), respectively) were used to explore the ability of two libraries of structurally distinct psychostimulants to inhibit... |
14685326 | Selective recognition of thymidylylthymidine (TpT) and antitumor effects of a macrocyclic dizinc(II) complex. | A polyamino dizinc(II) complex, [(N-bisdien)Zn2(II)Cl2](ClO4)2, (LZn), has been synthesized as a new nucleobase receptor molecule in aqueous solution at physiological pH, and shows to be highly selective in recognizing deoxythymidine (dT) and thymidylylthymidine (TpT). The strong acidic Zn(II) ions in LZn at the fifth ... |
14585933 | Locking the DNA topoisomerase I protein clamp inhibits DNA rotation and induces cell lethality. | Eukaryotic DNA topoisomerase I (Top1) is a monomeric protein clamp that functions in DNA replication, transcription, and recombination. Opposable "lip" domains form a salt bridge to complete Top1 protein clamping of duplex DNA. Changes in DNA topology are catalyzed by the formation of a transient phosphotyrosyl linkage... |
14585926 | The crystal structures of severe acute respiratory syndrome virus main protease and its complex with an inhibitor. | A newly identified severe acute respiratory syndrome coronavirus (SARS-CoV), is the etiological agent responsible for the outbreak of SARS. The SARS-CoV main protease, which is a 33.8-kDa protease (also called the 3C-like protease), plays a pivotal role in mediating viral replication and transcription functions through... |
14583594 | Revealing competitive Forster-type resonance energy-transfer pathways in single bichromophoric molecules. | We demonstrate measurements of the efficiency of competing Förster-type energy-transfer pathways in single bichromophoric systems by monitoring simultaneously the fluorescence intensity, fluorescence lifetime, and the number of independent emitters with time. Peryleneimide end-capped fluorene trimers, hexamers, and pol... |
14581615 | The two rotor components of yeast mitochondrial ATP synthase are mechanically coupled by subunit delta. | The mitochondrial ATP synthase is made of a membrane-integrated F0 component that forms a proton-permeable pore through the inner membrane and a globular peripheral F1 domain where ATP is synthesized. The catalytic mechanism is thought to involve the rotation of a 10-12 c subunit ring in the F0 together with the gamma ... |
14581613 | Transdifferentiation of mouse aortic smooth muscle cells to a macrophage-like state after cholesterol loading. | Mouse aortic smooth muscle cells (SMCs) were loaded for 72 h with cholesterol by using cholesterol:methyl-beta-cyclodextrin complexes, leading to approximately 2-fold and approximately 10-fold increases in the contents of total cholesterol and cholesteryl ester, respectively. Foam-cell formation was demonstrated by acc... |
14611653 | The septins. | The septins are guanine-nucleotide binding proteins that mostly form filaments. They are important in cytokinesis and also have roles in sporulation in yeasts and embryonic development and in the nervous system in animals. |
14611651 | Detergent-resistant membranes and the protein composition of lipid rafts. | The plasma membrane of eukaryotic cells contains lipid rafts with protein and lipid compositions differing from the bulk plasma membrane. Several recent proteomic studies have addressed the composition of lipid rafts, but the different definitions used for lipid rafts need scrutinizing before results can be evaluated. |
14581473 | Quantitative evaluation of the contribution of weak lysine-binding sites present within apolipoprotein(a) kringle IV types 6-8 to lipoprotein(a) assembly. | During lipoprotein(a) (Lp(a)) assembly, non-covalent interactions between apolipoprotein(a) (apo(a)) and low density lipoprotein precede specific disulfide bond formation. Studies have shown that the non-covalent step involves an interaction between the weak lysine-binding sites (WLBS) present within each of apo(a) kri... |
14578880 | Self-assembly of functional nanostructures from ABC triblock copolymers. | The spontaneous formation of nanostructured materials by molecular self-assembly of block copolymers is an active area of research, driven both by its inherent beauty and by a wealth of potential technological applications. Thin films of block copolymers have attracted increasing interest, particularly in view of possi... |
14576161 | The peptides acetyl-(Gly-3(S)Hyp-4(R)Hyp)10-NH2 and acetyl-(Gly-Pro-3(S)Hyp)10-NH2 do not form a collagen triple helix. | Hydroxylation of proline residues in the Yaa position of the Gly-Xaa-Yaa repeated sequence to 4(R)-hydroxyproline is essential for the formation of the collagen triple helix. A small number of 3(S)-hydroxyproline residues are present in most collagens in the Xaa position. Neither the structural nor a biological role is... |
14574456 | A novel transfecting peptide comprising a tetrameric nuclear localization sequence. | The transport of exogenous DNA into the nucleus of eukaryotic cells is a prerequisite for successful gene delivery. To favor nuclear transport we synthesized a tetramer of the nuclear localization signal (NLS) of the SV40 large T-antigen as a novel nonviral gene delivery vector. This 4.4-kDa lysine-rich peptide (NLSV40... |
14574492 | In vitro biological activities of transmembrane superantigen staphylococcal enterotoxin A fusion protein. | The bacterial superantigen staphylococcal enterotoxin A (SEA) stimulates T cells bearing certain TCR Vbeta domains when binding to MHC II molecules, and is a potent inducer of CTL activity and cytokine production. Antibody-targeted SEA such as C215 Fab-SEA and C242 Fab-SEA has been investigated for cancer therapy in re... |
14570906 | CD4 receptor localized to non-raft membrane microdomains supports HIV-1 entry. Identification of a novel raft localization marker in CD4. | Despite the preferential localization of CD4 to lipid rafts, the significance and role of these microdomains in HIV-1 entry is still controversial. The possibility that CD4, when localized to non-raft domains, might be able to support virus entry cannot be excluded. Because disintegration of rafts by extraction of cell... |
14569028 | Conformation-dependent hydrophobic photolabeling of the nicotinic receptor: electrophysiology-coordinated photochemistry and mass spectrometry. | We characterized the differential accessibility of the nicotinic acetylcholine receptor alpha1 subunit in the open, closed, and desensitized states by using electrophysiology-coordinated photolabeling by several lipophilic probes followed by mass spectrometric analysis. Voltage-clamped oocytes expressing receptors were... |
14565973 | Capacity of the golgi apparatus for biogenesis from the endoplasmic reticulum. | It is unclear whether the mammalian Golgi apparatus can form de novo from the ER or whether it requires a preassembled Golgi matrix. As a test, we assayed Golgi reassembly after forced redistribution of Golgi matrix proteins into the ER. Two conditions were used. In one, ER redistribution was achieved using a combinati... |
14566064 | Evolutionary specialization of a tryptophan indole group for transition-state stabilization by eukaryotic transglutaminases. | Covalent posttranslational protein modifications by eukaryotic transglutaminases proceed by a kinetic pathway of acylation and deacylation. Ammonia is released as the acylenzyme is formed, whereas the cross-linked product is released later in the deacylation step. Superposition of the active sites of transglutaminase t... |
14680505 | Ageing, autoimmunity and arthritis: Perturbations of TCR signal transduction pathways with ageing - a biochemical paradigm for the ageing immune system. | It is widely accepted that cell-mediated immune functions decline with age, rendering an individual more susceptible to infection and possibly cancer, as well as to age-associated autoimmune diseases. The exact causes of T-cell functional decline are not known. One possible cause could be the development of defects in ... |
14563683 | Discovery of a potent nanoparticle P-selectin antagonist with anti-inflammatory effects in allergic airway disease. | The severity of allergic asthma is dependent, in part, on the intensity of peribronchial inflammation. P-selectin is known to play a role in the development of allergen-induced peribronchial inflammation and airway hyperreactivity. Selective inhibitors of P-selectin-mediated leukocyte endothelial-cell interactions may ... |
14563648 | Dynamic regulation of Src-family kinases by CD45 in B cells. | CD45 is a key protein tyrosine phosphatase regulating Src-family protein tyrosine kinases (Src-PTKs) in lymphocytes; precisely how it exerts its effect remains controversial, however. We previously demonstrated that CD45 negatively regulates Lyn in the WEHI-231 B-cell line. Here we show that negative regulation by CD45... |
14561897 | Influenza virus hemagglutinin concentrates in lipid raft microdomains for efficient viral fusion. | Lipid raft microdomains are enriched in sphingomyelin and cholesterol and function as platforms for signal transduction and as the site of budding of several enveloped viruses, including influenza virus. The influenza virus hemagglutinin (HA) glycoprotein, which mediates both viral-cell attachment and membrane fusion, ... |
14557917 | Testosterone reinforcement: intravenous and intracerebroventricular self-administration in male rats and hamsters. | <h4>Rationale</h4>Anabolic steroids are drugs of abuse. However, the potential for addiction remains unclear. Testosterone induces conditioned place preference in rats and oral self-administration in hamsters.<h4>Objectives</h4>To determine if male rats and hamsters consume testosterone by intravenous (IV) or intracere... |
14561753 | Intra-Golgi protein transport depends on a cholesterol balance in the lipid membrane. | Transport of proteins between intracellular membrane compartments is mediated by a protein machinery that regulates the budding and fusion processes of individual transport steps. Although the core proteins of both processes are defined at great detail, much less is known about the involvement of lipids. Here we report... |
14559969 | DNA-mediated charge transport for DNA repair. | MutY, like many DNA base excision repair enzymes, contains a [4Fe4S]2+ cluster of undetermined function. Electrochemical studies of MutY bound to a DNA-modified gold electrode demonstrate that the [4Fe4S] cluster of MutY can be accessed in a DNA-mediated redox reaction. Although not detectable without DNA, the redox po... |
14605384 | Dichlorobis(imidazolidin-2-one-kappaO)zinc(II) at 150 K. | In the title compound, [ZnCl(2)(C(3)H(6)N(2)O)(2)], the zinc(II) cation is surrounded by a distorted tetrahedral environment consisting of two Cl anions and two imidazolidin-2-one molecules, the latter bound to the metal through their carbonyl O atoms. All atoms that are able to participate in hydrogen bonding are invo... |
14555650 | Atomic resolution structure of the HFBII hydrophobin, a self-assembling amphiphile. | Hydrophobins are proteins specific to filamentous fungi. Hydrophobins have several important roles in fungal physiology, for example, adhesion, formation of protective surface coatings, and the reduction of the surface tension of water, which allows growth of aerial structures. Hydrophobins show remarkable biophysical ... |
14551243 | Cholesterol depletion impairs vascular reactivity to endothelin-1 by reducing store-operated Ca2+ entry dependent on TRPC1. | The reactivity of the vascular wall to endothelin-1 (ET-1) is influenced by cholesterol, which is of possible importance for the progression of atherosclerosis. To elucidate signaling steps affected, the cholesterol acceptor methyl-beta-cyclodextrin (mbetacd, 10 mmol/L) was used to manipulate membrane cholesterol and d... |
14530928 | Molecular recognition between 4a S/R-galanthamine diastereoisomers and alpha-cyclodextrin. | Molecular recognition between 4a S/R-galanthamine diastereoisomers (1: 4a S-galanthamine;2: 4a R-galanthamine) and alpha-cyclodextrin (alpha-CD) were studied by use of docking and molecular dynamics (MD) simulation approaches. The binding energy of constructed 2...alpha-CD complexes is approximately 17 kcal mol(-1) low... |
14530278 | Cholesterol depletion results in site-specific increases in epidermal growth factor receptor phosphorylation due to membrane level effects. Studies with cholesterol enantiomers. | In A431 cells, depletion of cholesterol with methyl-beta-cyclodextrin induced an increase in both basal and epidermal growth factor (EGF)-stimulated EGF receptor phosphorylation. This increase in phosphorylation was site-specific, with significant increases occurring at Tyr845, Tyr992, and Tyr1173, but only minor chang... |
14530390 | The energetic cost of domain reorientation in maltose-binding protein as studied by NMR and fluorescence spectroscopy. | Maltose-binding protein (MBP) is a two-domain protein that undergoes a ligand-mediated conformational rearrangement from an "open" to a "closed" structure on binding to maltooligosaccharides. To characterize the energy landscape associated with this transition, we have generated five variants of MBP with mutations loca... |
14530413 | Enzyme screening with synthetic multifunctional pores: focus on biopolymers. | This report demonstrates that a single set of identical synthetic multifunctional pores can detect the activity of many different enzymes. Enzymes catalyzing either synthesis or degradation of DNA (exonuclease III or polymerase I), RNA (RNase A), polysaccharides (heparinase I, hyaluronidase, and galactosyltransferase),... |
14530408 | Facile synthesis of site-specifically acetylated and methylated histone proteins: reagents for evaluation of the histone code hypothesis. | The functional capacity of genetically encoded histone proteins can be powerfully expanded by posttranslational modification. A growing body of biochemical and genetic evidence clearly links the unique combinatorial patterning of side chain acetylation, methylation, and phosphorylation mainly within the highly conserve... |
14527957 | Efficient targeting of conserved cryptic epitopes of infectious agents by single domain antibodies. African trypanosomes as paradigm. | Antigen variation is a successful defense system adopted by several infectious agents to evade the host immune response. The principle of this defense strategy in the African trypanosome paradigm involves a dense packing of variant surface glycoproteins (VSG) exposing only highly variable and immuno-dominant epitopes t... |
14528017 | Endocytosis of epithelial apical junctional proteins by a clathrin-mediated pathway into a unique storage compartment. | The adherens junction (AJ) and tight junction (TJ) are key regulators of epithelial polarity and barrier function. Loss of epithelial phenotype is accompanied by endocytosis of AJs and TJs via unknown mechanisms. Using a model of calcium depletion, we defined the pathway of internalization of AJ and TJ proteins (E-cadh... |
14528016 | Dynamic and regulated association of caveolin with lipid bodies: modulation of lipid body motility and function by a dominant negative mutant. | Caveolins are a crucial component of caveolae but have also been localized to the Golgi complex, and, under some experimental conditions, to lipid bodies (LBs). The physiological relevance and dynamics of LB association remain unclear. We now show that endogenous caveolin-1 and caveolin-2 redistribute to LBs in lipid l... |
14528013 | Scavenger receptor BI (SR-BI) clustered on microvillar extensions suggests that this plasma membrane domain is a way station for cholesterol trafficking between cells and high-density lipoprotein. | Receptor-mediated trafficking of cholesterol between lipoproteins and cells is a fundamental biological process at the organismal and cellular levels. In contrast to the well-studied pathway of LDL receptor-mediated endocytosis, little is known about the trafficking of high-density lipoprotein (HDL) cholesterol by the ... |
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