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11735468 | Preparation, structure, and properties of the corner-shared double cubes [Mo(6)HgQ(8)(H(2)O)(18)](8+) (Q = S, Se) and tungsten analogues. | The purple corner-shared double cube [Mo(6)HgS(8)(H(2)O)(18)](8+) derivative of green [Mo(3)S(4)(H(2)O)(9)](4+), obtained under air-free conditions by the reaction with Hg(0) (metal), is also formed with Hg(I)(2). The Hg(I)(2) reaction is accounted for by the disproportionation Hg(I)(2) <==> Hg(0) + Hg(II), which is a ... |
11738187 | Deconstructing F(430): quantum chemical perspectives of biological methanogenesis. | What stabilizes the unique Ni(I) state of the active form of coenzyme F(430) and of methylcoenzyme M reductase, the enzyme responsible for the last methane-evolving step of biological methanogenesis? A survey of F(430) model compounds suggests that the monoanionic nature of the F(430) ligand goes a long way toward expl... |
11738185 | High-valent intermediates of heme proteins and model compounds. | Recent computational and experimental probes of high-valent intermediates in heme proteins and model compounds reveal a rich spectrum of chemical behavior that is dependent on the nature of the proximal ligand, metal center, distal- and proximal-binding site environment, porphyrin macrocycle architecture, and consequen... |
11738176 | Synthetic self-assembled models with biomimetic functions. | Self-assembly can be considered a powerful tool in the hand of chemists for the understanding, modeling and mimicking of biological systems. The possibility of reproducing biological functions in synthetic systems obtained by self-assembly is envisioned as a modest but very important step towards the understanding of t... |
11738175 | Protein-protein interfaces: mimics and inhibitors. | Many biological processes are mediated by specific molecular recognition between proteins. However, the thermodynamic and structural 'rules' for such recognition are incompletely understood, as is the potential for inhibition by small molecules. Recent progress has included the discovery of small-molecule inhibitors fo... |
11736883 | Pharmacokinetics of finrozole (MPV-2213ad), a novel selective aromatase inhibitor, in healthy men. | <h4>Aims</h4>To investigate the pharmacokinetics of finrozole (MPV-2213ad), a novel competitive aromatase enzyme inhibitor, in healthy male volunteers.<h4>Methods</h4>The study was an open, partly randomized cross-over study including 23 volunteers receiving single doses of 3, 9 mg or 30 mg of finrozole as tablets or s... |
11739199 | The antitumor ether lipid ET-18-OCH(3) induces apoptosis through translocation and capping of Fas/CD95 into membrane rafts in human leukemic cells. | The antitumor ether lipid ET-18-OCH(3) promotes apoptosis in tumor cells through intracellular activation of Fas/CD95. Results of this study showed that ET-18-OCH(3) induces cocapping of Fas and membrane rafts, specialized plasma membrane regions involved in signaling, before the onset of apoptosis in human leukemic ce... |
11735426 | G(s) signaling is intact after disruption of lipid rafts. | Membrane microdomains enriched in cholesterol and sphingolipids modulate a number of signal transduction pathways and provide a residence for heterotrimeric G proteins, their receptors, and their effectors. We investigated whether signaling through G(s) was dependent on these membrane domains, characterized by their re... |
11735411 | Production of phosphatidylinositol 3,4,5-trisphosphate and phosphatidic acid in platelet rafts: evidence for a critical role of cholesterol-enriched domains in human platelet activation. | Glycosphingolipid- and cholesterol-enriched membrane microdomains, called rafts, can be isolated from several mammalian cells, including platelets. These microdomains appear to play a critical role in signal transduction in several hematopoietic cells, but their function in blood platelets remains unknown. Herein, we f... |
11735389 | The affinity-enhancing roles of flexible linkers in two-domain DNA-binding proteins. | Recently many attempts have been made to design high-affinity DNA-binding proteins by linking two domains. Here a theory for guiding these designs is presented. Flexible linkers may play three types of roles: (a) linking domains which by themselves are unfolded and bind to DNA only as a folded dimer (as in a designed s... |
11736640 | The Phox homology (PX) domain, a new player in phosphoinositide signalling. | Phosphoinositides are key regulators of diverse cellular processes. The pleckstrin homology (PH) domain mediates the action of PtdIns(3,4)P(2), PtdIns(4,5)P(2) and PtdIns(3,4,5)P(3), while the FYVE domain relays the pulse of PtdIns3P. The recent establishment that the Phox homology (PX) domain interacts with PtdIns3P a... |
11735865 | Incidence and reversibility of organ failure in the course of sterile or infected necrotizing pancreatitis. | <h4>Background</h4>Multiple organ failure (MOF) and infected necrosis are both considered severe adverse events during the course of necrotizing pancreatitis.<h4>Hypothesis</h4>The incidence of MOF and its reversibility in patients with necrotizing pancreatitis are influenced by the presence or absence of infected necr... |
11734617 | International Union of Pharmacology. XXV. Nomenclature and classification of adenosine receptors. | Four adenosine receptors have been cloned and characterized from several mammalian species. The receptors are named adenosine A(1), A(2A), A(2B), and A(3). The A(2A) and A(2B) receptors preferably interact with members of the G(s) family of G proteins and the A(1) and A(3) receptors with G(i/o) proteins. However, other... |
11734002 | Flexibility and nucleation in sickle hemoglobin. | We have studied the self-assembly of Hemoglobin C-Harlem (HbC-Harlem), a double mutant of hemoglobin that possesses the beta6 Glu-->Val mutation of sickle hemoglobin (HbS) plus beta73 Asp-->Asn. By electron microscopy we find it forms crystals, rather than the wrapped multistranded fibers seen in HbS. Fourier transform... |
11733996 | Structure and properties of a dimeric N-terminal fragment of human ubiquitin. | Previous peptide dissection and kinetic experiments have indicated that in vitro folding of ubiquitin may proceed via transient species in which native-like structure has been acquired in the first 45 residues. A peptide fragment, UQ(1-51), encompassing residues 1 to 51 of ubiquitin was produced in order to test whethe... |
11734041 | Lattice-Boltzmann simulations of self-assembly of a binary water-surfactant system into ordered bicontinuous cubic and lamellar phases. | We used our recently developed mesoscale amphiphilic lattice-Boltzmann method (Nekovee, M.; Coveney, P. V.; Chen, H.; Boghosian, B. M. Phys. Rev. E 2000, 62, 8282-8894) to investigate the dynamics of self-assembly of the bicontinuous cubic phase in a binary water-surfactant system, and the transition from the lamellar ... |
11734023 | Photochromic atropisomer generation and conformation determination in a ruthenium bis(bipyridine) phosphonite gamma-cyclodextrin system. | Irradiation of rac-[Ru(bpy)(2)(PhP(OMe)(2))(Cl)]Cl (2) at lambda > 460 nm results in the photochromic generation of a new atropisomer and chirality inversion, via rotation of the PhP(OMe)(2) moiety around the Ru-P bond. However, since the energetic barrier to rotation is low resulting in racemization, it was found that... |
11734017 | New efficient calixarene amide ionophores for the selective removal of strontium ion from nuclear waste: synthesis, complexation, and extraction properties. | Three novel lower rim hexamide derivatives 5(6), 7(6), and 9(6) of p-hydroxycalix[6]arene and four octamides 5(8), 7(8)-9(8) derived from the corresponding p-hydroxycalix[8]arene were synthesized, and their potential as extractants in radioactive waste treatment was evaluated, in comparison with upper rim analogues 12(... |
11817307 | Direct chiral assay of tramadol and detection of the phase II metabolite O-demethyl tramadol glucuronide in human urine using capillary electrophoresis with laser-induced native fluorescence detection. | A chiral separation using carboxymethyl-beta-cyclodextrin and methyl-beta-cyclodextrin for the direct assay of tramadol in human urine by capillary electrophoresis (CE) with laser-induced native fluorescence detection was developed. Furthermore, the phase II metabolite O-demethyl tramadol glucuronide was determined fro... |
11733582 | Hepatocyte nuclear factor 1alpha controls the expression of terminal complement genes. | The terminal components of the complement system contribute to host defense by forming the multiprotein membrane attack complex (MAC) which is responsible for cell lysis and several noncytotoxic effects. Most of the complement proteins are synthesized in the liver, but the mechanisms controlling their tissue-specific e... |
11733575 | Complement 1 inhibitor is a regulator of the alternative complement pathway. | We studied complement 1 inhibitor (C1-INH) as an inhibitor of the alternative complement pathway. C1-INH prevented lysis, induced by the alternative complement pathway, of paroxysmal nocturnal hemoglobinuria (PNH) erythrocytes in human serum. It inhibited the binding of both factors B and C3 to PNH and rabbit erythrocy... |
11732892 | Spontaneous in vitro formation of supramolecular beta-amyloid structures, "betaamy balls", by beta-amyloid 1-40 peptide. | The concentration of beta-amyloid peptide (Abeta), x-42 or x-40 amino acids long, increases in brain with the progression Alzheimer's disease (AD). These peptides are deposited extracellularly as highly insoluble fibrils that form densities of amyloid plaques. Abeta fibrillization is a complex polymerization process pr... |
11733378 | Identification of receptor-binding sites of monocyte chemotactic S19 ribosomal protein dimer. | The S19 ribosomal protein (RP S19) cross-linked homo-dimer attracts monocyte migration by binding to C5a receptor on monocytes (H Nishiura, Y Shibuya, T Yamamoto, Laboratory Investigation, 1998, 78:1615-1623). Using site-directed mutants of recombinant RP S19 and synthetic peptides mimicking RP S19 molecular regions, w... |
11733375 | A dominant interference collagen X mutation disrupts hypertrophic chondrocyte pericellular matrix and glycosaminoglycan and proteoglycan distribution in transgenic mice. | Collagen X transgenic (Tg) mice displayed skeleto-hematopoietic defects in tissues derived by endochondral skeletogenesis.(1) Here we demonstrate that co-expression of the transgene product containing truncated chicken collagen X with full-length mouse collagen X in a cell-free translation system yielded chicken-mouse ... |
11733349 | Deposition of transthyretin in early stages of familial amyloidotic polyneuropathy: evidence for toxicity of nonfibrillar aggregates. | Familial amyloidotic polyneuropathy (FAP) is a neurodegenerative disorder characterized by extracellular deposition of transthyretin (TTR) amyloid fibrils, particularly in the peripheral nervous system. No systematic immunohistochemical data exists relating TTR deposition with FAP progression. We assessed nerves from F... |
11731584 | Na+-H+ exchanger 3 (NHE3) is present in lipid rafts in the rabbit ileal brush border: a role for rafts in trafficking and rapid stimulation of NHE3. | 1. Rabbit ileal Na+-absorbing cell Na+-H+ exchanger 3 (NHE3) was shown to exist in three pools in the brush border (BB), including a population in lipid rafts. Approximately 50% of BB NHE3 was associated with Triton X-100-soluble fractions and the other approximately 50% with Triton X-100-insoluble fractions; approxima... |
11731480 | The silencing complex SAS-I links histone acetylation to the assembly of repressed chromatin by CAF-I and Asf1 in Saccharomyces cerevisiae. | The acetylation state of histones plays a central role in determining gene expression in chromatin. The reestablishment of the acetylation state of nucleosomes after DNA replication and chromatin assembly requires both deacetylation and acetylation of specific lysine residues on newly incorporated histones. In this stu... |
11731479 | The yeast SAS (something about silencing) protein complex contains a MYST-type putative acetyltransferase and functions with chromatin assembly factor ASF1. | It is well established that acetylation of histone and nonhistone proteins is intimately linked to transcriptional activation. However, loss of acetyltransferase activity has also been shown to cause silencing defects, implicating acetylation in gene silencing. The something about silencing (Sas) 2 protein of Saccharom... |
11730811 | Apolipoprotein AI and HDL(3) inhibit spreading of primary human monocytes through a mechanism that involves cholesterol depletion and regulation of CDC42. | The objective of the current study was to characterize the influence of high density lipoproteins (HDL) on processes related to the vascular recruitment of human monocytes, which may contribute to the anti-atherogenic properties of these lipoproteins. We show that HDL(3) and apo AI inhibit the following processes in pr... |
11731029 | Cyclodextrins in oligonucleotide delivery. | The aim of this contribution is to summarize recent findings on the potential use of cyclodextrins and their derivatives as carriers for oligonucleotide agents. Their peculiar properties could be exploited in such an emerging therapeutic area by virtue of their capability of interacting with cellular membranes, thus gi... |
11728398 | Two stereoisomeric 3(I),2(II)-anhydro-alpha-cyclodextrins: a molecular dynamics and crystallographic study. | Regioselective epoxide ring opening of 2(I),3(I)-(2(I)S)-anhydro-alpha-cyclodextrin (1) through intramolecular attack of hydroxyl groups of neighboring glucose rings occurs in diequatorial fashion to yield 3(I),2(II)-anhydro-alpha-cyclodextrin (3) with a rigid glucopyranose-dioxane-glucopyranose tricyclic ring system, ... |
11726695 | Molecular recognition of pyr mRNA by the Bacillus subtilis attenuation regulatory protein PyrR. | The pyrimidine nucleotide biosynthesis (pyr) operon in Bacillus subtilis is regulated by transcriptional attenuation. The PyrR protein binds in a uridine nucleotide-dependent manner to three attenuation sites at the 5'-end of pyr mRNA. PyrR binds an RNA-binding loop, allowing a terminator hairpin to form and repressing... |
11726539 | DNA methylation-dependent chromatin fiber compaction in vivo and in vitro: requirement for linker histone. | Dynamic alterations in chromatin structure mediated by postsynthetic histone modifications and DNA methylation constitute a major regulatory mechanism in DNA functioning. DNA methylation has been implicated in transcriptional silencing, in part by inducing chromatin condensation. To understand the methylation-dependent... |
11726524 | The intracellular location of two aminoacyl-tRNA synthetases depends on complex formation with Arc1p. | In yeast, two aminoacyl-tRNA synthetases, MetRS and GluRS, are associated with Arc1p. We have studied the mechanism of this complex formation and found that the non-catalytic N-terminally appended domains of MetRS and GluRS are necessary and sufficient for binding to Arc1p. Similarly, it is the N-terminal domain of Arc... |
11726505 | Glycosylation influences cross-species formation of protease-resistant prion protein. | A key event in the transmissible spongiform encephalopathies (TSEs) is the formation of aggregated and protease-resistant prion protein, PrP-res, from a normally soluble, protease-sensitive and glycosylated precursor, PrP-sen. While amino acid sequence similarity between PrP-sen and PrP-res influences both PrP-res form... |
11726186 | Studies of a disposable biosensor based on the beta-cyclodextrin inclusion complex as mediator. | This paper reports the use of a disposable voltammetric biosensor based on a screen-printed basal electrode and highly efficient mediators, the beta-cyclodextrin inclusion complexes tetramethylbenzidine and ferrocene. The polyphenol oxidase, contained in the crude extract of mushroom, was immobilized in the membrane of... |
11724915 | The role of glycation in the pathogenesis of diabetic polyneuropathy. | The most common neuropathy associated with diabetes mellitus is a distal sensory polyneuropathy. The relative importance of the direct effects of prolonged glycaemia on nervous tissue compared with indirect damage resulting from changes in blood vessels is not known. Although the importance of glycaemia is confirmed by... |
11724606 | A novel, tunable manganese coordination system based on a flexible "spacer" unit: noncovalent templation effects. | The reaction of bis(hexafluoroacetylacetonato)manganese(II) trihydrate (2), an approximately 90 degrees corner unit, with flexible linking unit 4,4'-trimethylenedipyridine (1) allows for the potential formation of three different types of solid-state coordination species: infinite helical polymers, closed dimeric syste... |
11724605 | Tubular hydrogen-bonded networks sustained by water molecules. | The design concept of functional solids relies on controlling the topology of crystal packing through exploitation of weak intermolecular forces. In the context of cyclic aggregates, the ability to anticipate the consequences of ring constituents and their stereochemistries on ring conformation is vitally important sin... |
11724591 | Effect of peracylation of beta-cyclodextrin on the molecular structure and on the formation of inclusion complexes: an X-ray study. | The molecular structures of peracylated beta-cyclodextrins (CDs)--heptakis(2,3,6-tri-O-acetyl)-beta-CD (TA), heptakis(2,3,6-tri-O-propanoyl)-beta-CD (TP), and heptakis(2,3,6-tri-O-butanoyl)-beta-CD (TB)--have been determined by single crystal X-ray structure analysis. Due to the lack of O2...O3' hydrogen bonds between ... |
11724744 | The interaction between ethanol and pregnanolone at induction of anaesthesia investigated with a threshold method in male rats. | 1. An anaesthesia threshold was used to investigate the pharmacodynamic and pharmacokinetic interactions between ethanol and pregnanolone in male rats. 2. The criterion to determine threshold doses of pregnanolone was the first burst suppression of 1 s in the EEG. 3. Ethanol (0.5, 1.0, 1.5 and 2.0 g kg(-1)) was injecte... |
11724577 | Mass spectrometric analysis reveals an increase in plasma membrane polyunsaturated phospholipid species upon cellular cholesterol loading. | Here we used electrospray ionization mass spectrometry for quantitative determination of lipid molecular species in human fibroblasts and their plasma membrane incorporated into enveloped viruses. Both influenza virus selecting ordered domains and vesicular stomatitis virus (VSV) depleted of such domains [Scheiffele, P... |
11724549 | Host-guest study of left-handed polyproline II helix formation. | The importance of the left-handed polyproline II (PPII) helical conformation has recently become apparent. This conformation generally is involved in two important functions: protein-protein interactions and structural integrity. PPII helices play vital roles in a variety of processes including signal transduction, tra... |
11722894 | Novel Zn(2+)-chelating peptides selected from a fimbria-displayed random peptide library. | The display of peptide sequences on the surface of bacteria is a technology that offers exciting applications in biotechnology and medical research. Type 1 fimbriae are surface organelles of Escherichia coli which mediate D-mannose-sensitive binding to different host surfaces by virtue of the FimH adhesin. FimH is a co... |
11720495 | Neutral dodecanuclear supramolecular complexes containing dimetal units linked by the trimesate anion. | Two compounds having six metal-metal bonded Mo(2)(4+) and Rh(2)(4+) units, the midpoints of which occupy the vertexes of an octahedron, are described here. Each of the M(2)(4+) units is also bridged by two mutually cis formamidinate groups of the type DAniF = N,N'-di-p-anisylformamidinate. These units are linked to eac... |
11720491 | Cd(II) and Pb(II) complexation by dipyridine-containing macrocycles with different molecular architecture. Effect of complex protonation on metal coordination environment. | The coordination features of the three dipyridine-containing polyamine macrocycles 2,5,8,11,14-pentaaza[15]-[15](2,2')[1,15]-bipyridylophane (L1), 5,8,11-trimethyl-2,5,8,11,14-pentaaza[15]-[15](2,2')[1,15]-bipyridylophane (L2), and 4,4'-(2,5,8,11,14-pentaaza[15]-[15](2,2')-bipyridylophane) (L3) toward Cd(II) and Pb(II)... |
11721004 | Additional hydrogen bonds and base-pair kinetics in the symmetrical AMP-DNA aptamer complex. | The solution structure of an adenosine monophosphate (AMP)-DNA aptamer complex has been determined previously [Lin, C. H., and Patel, D. J. (1997) Chem. Biol. 4:817-832]. On a symmetrical aptamer complex containing the same binding loop, but with better resolved spectra, we have identified two additional hydrogen bond-... |
11720984 | Deformation-enhanced fluctuations in the red cell skeleton with theoretical relations to elasticity, connectivity, and spectrin unfolding. | To assess local elasticity in the red cell's spectrin-actin network, nano-particles were tethered to actin nodes and their constrained thermal motions were tracked. Cells were both immobilized and controllably deformed by aspiration into a micropipette. Since the network is well-appreciated as soft, thermal fluctuation... |
11720982 | The sensitivity of saturation transfer electron paramagnetic resonance spectra to restricted amplitude uniaxial rotational diffusion. | Computational methods have been developed to model the effects of constrained or restricted amplitude uniaxial rotational diffusion (URD) on saturation transfer electron paramagnetic resonance (ST-EPR) signals observed from nitroxide spin labels. These methods, which have been developed to model the global rotational m... |
11720981 | The binding dynamics of tropomyosin on actin. | We discuss a theoretical model for the cooperative binding dynamics of tropomyosin to actin filaments. Tropomyosin binds to actin by occupying seven consecutive monomers. The model includes a strong attraction between attached tropomyosin molecules. We start with an empty lattice and show that the binding goes through ... |
11720977 | Electrostatic analysis and Brownian dynamics simulation of the association of plastocyanin and cytochrome f. | The oxidation of cytochrome f by the soluble cupredoxin plastocyanin is a central reaction in the photosynthetic electron transfer chain of all oxygenic organisms. Here, two different computational approaches are used to gain new insights into the role of molecular recognition and protein-protein association processes ... |
11718675 | Immunosensors--principles and applications to clinical chemistry. | <h4>Introduction</h4>Immunosensors are affinity ligand-based biosensor solid-state devices in which the immunochemical reaction is coupled to a transducer. The fundamental basis of all immunosensors is the specificity of the molecular recognition of antigens by antibodies to form a stable complex. This is similar to th... |
11718668 | Calsequestrin binds to monomeric and complexed forms of key calcium-handling proteins in native sarcoplasmic reticulum membranes from rabbit skeletal muscle. | Ca(2+)-handling proteins are important regulators of the excitation-contraction-relaxation cycle in skeletal muscle fibres. Although domain binding studies suggest protein coupling between various Ca(2+)-regulatory elements of triad junctions, no direct biochemical evidence exists demonstrating high-molecular-mass comp... |
11717370 | Functional interactions between tumor and peripheral nerve: changes in excitability and morphology of primary afferent fibers in a murine model of cancer pain. | We used a murine model to investigate functional interactions between tumors and peripheral nerves that may contribute to pain associated with cancer. Implantation of fibrosarcoma cells in and around the calcaneus bone produced mechanical hyperalgesia of the ipsilateral paw. Electrophysiological recordings from primary... |
11717287 | Display of passenger proteins on the surface of Escherichia coli K-12 by the enterohemorrhagic E. coli intimin EaeA. | Intimins are members of a family of bacterial adhesins from pathogenic Escherichia coli which specifically interact with diverse eukaryotic cell surface receptors. The EaeA intimin from enterohemorrhagic E. coli O157:H7 contains an N-terminal transporter domain, which resides in the bacterial outer membrane and promote... |
11717268 | The staphylococcal QacR multidrug regulator binds a correctly spaced operator as a pair of dimers. | Expression of the Staphylococcus aureus plasmid-encoded QacA multidrug transporter is regulated by the divergently encoded QacR repressor protein. To circumvent the formation of disulfide-bonded degradation products, site-directed mutagenesis to replace the two cysteine residues in wild-type QacR was undertaken. Analys... |
11717255 | MxiM and MxiJ, base elements of the Mxi-Spa type III secretion system of Shigella, interact with and stabilize the MxiD secretin in the cell envelope. | The type III secretion pathway is broadly distributed across many parasitic bacterial genera and serves as a mechanism for delivering effector proteins to eukaryotic cell surface and cytosolic targets. While the effectors, as well as the host responses elicited, differ among type III systems, they all utilize a conserv... |
11717027 | Acute type A aortic dissection: the prognostic impact of preoperative cardiac tamponade. | <h4>Objective</h4>Acute type A aortic dissection requires emergency surgery and is associated with considerable mortality. The aim of the study was to evaluate whether occurrence of preoperative cardiac tamponade with or without palpable pulses in these patients is associated with higher incidence of multiple organ fai... |
11714926 | Molecular design of Mycoplasma hominis Vaa adhesin. | The variable adherence-associated (Vaa) adhesin of the opportunistic human pathogen Mycoplasma hominis is a surface-exposed, membrane-associated protein involved in the attachment of the bacterium to host cells. The molecular masses of recombinant 1 and 2 cassette forms of the protein determined by a light-scattering (... |
11714922 | Solution conditions can promote formation of either amyloid protofilaments or mature fibrils from the HypF N-terminal domain. | The HypF N-terminal domain has been found to convert readily from its native globular conformation into protein aggregates with the characteristics of amyloid fibrils associated with a variety of human diseases. This conversion was achieved by incubation at acidic pH or in the presence of moderate concentrations of tri... |
11714918 | Substitution rates in alpha-helical transmembrane proteins. | It has been shown previously that some membrane proteins have a conserved core of amino acid residues. This idea not only serves to orient helices during model building exercises but may also provide insight into the structural role of residues mediating helix-helix interactions. Using experimentally determined high-re... |
11713268 | Structure-function analysis of Lyn kinase association with lipid rafts and initiation of early signaling events after Fcepsilon receptor I aggregation. | The first step in immunoreceptor signaling is represented by ligand-dependent receptor aggregation, followed by receptor phosphorylation mediated by tyrosine kinases of the Src family. Recently, sphingolipid- and cholesterol-rich plasma membrane microdomains, called lipid rafts, have been identified and proposed to fun... |
11713264 | Saturation mutagenesis of 5S rRNA in Saccharomyces cerevisiae. | rRNAs are the central players in the reactions catalyzed by ribosomes, and the individual rRNAs are actively involved in different ribosome functions. Our previous demonstration that yeast 5S rRNA mutants (called mof9) can impact translational reading frame maintenance showed an unexpected function for this ubiquitous ... |
11711617 | Adaptive mutations in the V3 loop of gp120 enhance fusogenicity of human immunodeficiency virus type 1 and enable use of a CCR5 coreceptor that lacks the amino-terminal sulfated region. | To identify sites in gp120 that interact with the CCR5 coreceptor and to analyze the mechanisms of infection, we selected variants of the CCR5-dependent JRCSF molecular clone of human immunodeficiency virus type 1 (HIV-1) that adapted to replicate in HeLa-CD4 cells that express the mutant coreceptor CCR5(Y14N) or CCR5(... |
11711585 | Functional mapping of the DNA binding domain of bovine papillomavirus E1 protein. | Bovine papillomavirus type 1 (BPV-1) requires viral proteins E1 and E2 for efficient DNA replication in host cells. E1 functions at the BPV origin as an ATP-dependent helicase during replication initiation. Previously, we used alanine mutagenesis to identify two hydrophilic regions of the E1 DNA binding domain (E1DBD),... |
11709300 | Dicyclic and tricyclic diaminopyrimidine derivatives as potent inhibitors of Cryptosporidium parvum dihydrofolate reductase: structure-activity and structure-selectivity correlations. | A structurally diverse library of 93 lipophilic di- and tricyclic diaminopyrimidine derivatives was tested for the ability to inhibit recombinant dihydrofolate reductase (DHFR) cloned from human and bovine isolates of Cryptosporidium parvum (J. R. Vásquez et al., Mol. Biochem. Parasitol. 79:153-165, 1996). In parallel,... |
11705966 | Localization of functional domains of the mitogenic toxin of Pasteurella multocida. | The locations of the catalytic and receptor-binding domains of the Pasteurella multocida toxin (PMT) were investigated. N- and C-terminal fragments of PMT were cloned and expressed as fusion proteins with affinity tags. Purified fusion proteins were assessed in suitable assays for catalytic activity and cell-binding ab... |
11705892 | Effect of 6-hydroxydopamine on host resistance against Listeria monocytogenes infection. | Recent studies have shown that immunocompetent cells bear receptors of neuropeptides and neurotransmitters and that these ligands play roles in the immune response. In this study, the role of the sympathetic nervous system in host resistance against Listeria monocytogenes infection was investigated in mice pretreated w... |
11698167 | Analysis of interleukin-8 release from normal human epidermal keratinocytes exposed to aliphatic hydrocarbons: delivery of hydrocarbons to cell cultures via complexation with alpha-cyclodextrin. | While inhalation exposures represent the predominant route for jet fuel toxicity, increased concern has been placed on topical exposures due to reports of severe contact dermatitis among military personnel. All three of the predominant aviation fuels currently used by the commercial and military sectors have been demon... |
11698387 | The rlmB gene is essential for formation of Gm2251 in 23S rRNA but not for ribosome maturation in Escherichia coli. | In Saccharomyces cerevisiae, the rRNA Gm2270 methyltransferase, Pet56p, has an essential role in the maturation of the mitochondrial large ribosomal subunit that is independent of its methyltransferase activity. Here we show that the proposed Escherichia coli ortholog, RlmB (formerly YjfH), indeed is essential for the ... |
11689695 | Rna15 interaction with the A-rich yeast polyadenylation signal is an essential step in mRNA 3'-end formation. | In Saccharomyces cerevisiae, four factors [cleavage factor I (CF I), CF II, polyadenylation factor I (PF I), and poly(A) polymerase (PAP)] are required for maturation of the 3' end of the mRNA. CF I and CF II are required for cleavage; a complex of PAP and PF I, which includes CF II subunits, participates in polyadenyl... |
11689670 | Two point mutations produce infectious retrovirus bearing a green fluorescent protein-SU fusion protein. | Two second-site mutations in Moloney murine leukemia virus envelope surface protein (SU) were previously shown to rescue infection of two different SU mutants, a fusion-defective point mutant and a fusion-defective modified SU that exhibits weak subunit association. We report here that they also rescue infection of a t... |
11689620 | Cross-reactivity between hepatitis C virus and Influenza A virus determinant-specific cytotoxic T cells. | The cellular immune response contributes to viral clearance as well as to liver injury in acute and chronic hepatitis C virus (HCV) infection. An immunodominant determinant frequently recognized by liver-infiltrating and circulating CD8(+) T cells of HCV-infected patients is the HCV(NS3-1073) peptide CVNGVCWTV. Using a... |
11679285 | Photosystem II-based biosensors for the detection of pollutants. | Photosystem II (PSII) is the supramolecular pigment-protein complex in the chloroplast, which catalyses the light-induced transfer of electrons from water to plastoquinone (PQ) in a process that evolves oxygen. The PSII complex is also known to bind some groups of (photosynthetic) herbicides, heavy metals and other che... |
11600308 | Development of a simple, rapid and reproducible HPLC assay for the simultaneous determination of hypericins and stabilized hyperforin in commercial St. John's wort preparations. | A reversed-phase HPLC method was developed and validated for the simultaneous determination of hypericins and stabilized hyperforin in St. John's wort extract. The sample solution was prepared by extraction of the finely powdered extract with methanol-water (80:20, v/v) containing 5% HP-beta-cyclodextrin, and adjusted ... |
11717486 | Associations of squaric acid and its anions as multiform building blocks of hydrogen-bonded molecular crystals. | Squaric acid, H(2)C(4)O(4) (H(2)SQ), is a completely flat diprotic acid that can crystallize as such, as well as in three different anionic forms, i.e. H(2)SQ.HSQ(-), HSQ(-) and SQ(2-). Its interest for crystal engineering studies arises from three notable factors: (i) its ability of donating and accepting hydrogen bon... |
11724808 | Caveolin-1 is a negative regulator of caveolae-mediated endocytosis to the endoplasmic reticulum. | Caveolae are flask-shaped invaginations at the plasma membrane that constitute a subclass of detergent-resistant membrane domains enriched in cholesterol and sphingolipids and that express caveolin, a caveolar coat protein. Autocrine motility factor receptor (AMF-R) is stably localized to caveolae, and the cholesterol ... |
11724962 | Complement activation in factor D-deficient mice. | To assess the contribution of the alternative pathway in complement activation and host defense and its possible role in the regulation of systemic energy balance in vivo, factor D-deficient mice were generated by gene targeting. The mutant mice have no apparent abnormality in development and their body weights are sim... |
11724944 | Compressive nonlinearity in the hair bundle's active response to mechanical stimulation. | The auditory system's ability to interpret sounds over a wide range of amplitudes rests on the nonlinear responsiveness of the ear. Whether measured by basilar-membrane vibration, nerve-fiber activity, or perceived loudness, the ear is most sensitive to small signals and grows progressively less responsive as stimulati... |
11724921 | Signaling at the inhibitory natural killer cell immune synapse regulates lipid raft polarization but not class I MHC clustering. | Natural killer (NK) cell cytotoxicity is determined by a balance of positive and negative signals. Negative signals are transmitted by NK inhibitory receptors (killer immunoglobulin-like receptors, KIR) at the site of membrane apposition between an NK cell and a target cell, where inhibitory receptors become clustered ... |
11737874 | Expense and benefit of neoadjuvant treatment in squamous cell carcinoma of the esophagus. | <h4>Background</h4>The effectiveness of neoadjuvant treatment (NT) prior to resection of squamous cell carcinoma of the esophagus (SCCE) in terms of prolonged survival has not been proven by randomized trials. Facing considerable financial expenses and with concerns regarding the consumption of the patient's remaining ... |
11907655 | Pitfalls in gastrointestinal permeability measurement in ICU patients with multiple organ failure using differential sugar absorption. | <h4>Objective</h4>To assess whether gastrointestinal permeability (GIP) at intensive care unit (ICU) admission, measured by differential sugar absorption, is related to severity of disease and multiple organ failure (MOF). Post hoc, to analyse the relation between the urinary sugar recovery and renal function.<h4>Desig... |
11845331 | An antibody to recombinant crustacean hyperglycaemic hormone of Nephrops norvegicus cross-reacts with neuroendocrine organs of several taxa of malacostracan Crustacea. | The crustacean hyperglycaemic hormones (cHHs) are multifunctional neuropeptides that play a central role in the physiology of crustaceans. A partial cDNA coding for cHH of the Norway lobster, Nephrops norvegicus, was cloned; this cDNA was fused to glutathione- S-transferase (GST) to obtain a recombinant fusion protein ... |
11736179 | Intrinsic viscosity and the electrical polarizability of arbitrarily shaped objects. | The problem of calculating the electric polarizability tensor alpha(e) of objects of arbitrary shape has been reformulated in terms of path integration and implemented computationally. The method simultaneously yields the electrostatic capacity C and the equilibrium charge density. These functionals of particle shape a... |
11717404 | Coexisting conformations of fibronectin in cell culture imaged using fluorescence resonance energy transfer. | Fluorescence resonance energy transfer (FRET) between fluorophores attached to single proteins provides a tool to study the conformation of proteins in solution and in cell culture. As a protein unfolds, nanometer-scale increases in distance between donor and acceptor fluorophores cause decreases in FRET. Here we demon... |
11707586 | Distinction between signaling mechanisms in lipid rafts vs. caveolae. | The relative importance of lipid rafts vs. specialized rafts termed caveolae to influence signal transduction is not known. Here we show that in cells lacking caveolae, the dually acylated protein, endothelial nitric oxide synthase (eNOS), localizes to cholesterol-rich lipid raft domains of the plasma membrane. In thes... |
11707577 | Surface organization and nanopatterning of collagen by dip-pen nanolithography. | Collagen is a key fibrous protein in biological systems, characterized by a complex structural hierarchy as well as the ability to self-assemble into liquid crystalline mesophases. The structural features of collagen influence cellular responses and material properties, with importance for a wide range of biomaterials ... |
11706054 | Ectodomain shedding of L1 adhesion molecule promotes cell migration by autocrine binding to integrins. | The L1 adhesion molecule plays an important role in axon guidance and cell migration in the nervous system. L1 is also expressed by many human carcinomas. In addition to cell surface expression, the L1 ectodomain can be released by a metalloproteinase, but the biological function of this process is unknown. Here we dem... |
11696539 | The remote substrate binding subsite -6 in cyclodextrin-glycosyltransferase controls the transferase activity of the enzyme via an induced-fit mechanism. | Cyclodextrin-glycosyltransferase (CGTase) catalyzes the formation of alpha-, beta-, and gamma-cyclodextrins (cyclic alpha-(1,4)-linked oligosaccharides of 6, 7, or 8 glucose residues, respectively) from starch. Nine substrate binding subsites were observed in an x-ray structure of the CGTase from Bacillus circulans str... |
29712266 | Enantiomeric Discrimination in a Reiterative Domino Coupling Process: Cu<sup>I</sup> -mediated Syn Cyclotrimerization of Racemic Polycyclic Trimethylstannyl Bromonorbornadienes. | The challenge to generate all-syn architecture has prompted the synthesis of syn cyclotrimers 2 from racemic bromotrimethylstannyl polycyclic alkenes 1. The syn-selective Cu<sup>I</sup> -catalyzed cyclotrimerization process is both regio- and chemoselective. |
29712257 | Solvothermal Synthesis of a 24-Nuclear, Cube-Shaped Squarato-oxovanadium(IV) Framework: [N(nBu)<sub>4</sub> ]<sub>8</sub> [V<sub>24</sub> O<sub>24</sub> (C<sub>4</sub> O<sub>4</sub> )<sub>12</sub> (OCH<sub>3</sub> )<sub>32</sub> ]. | Polydentate bridging ligands can be used to link small polyoxo-alkoxo-metalate units to form supramolecular clusters. In the title compound, twelve μ<sub>4</sub> -bridging squarato groups connect eight trinuclear methoxo-oxo-vanadate units to form a tetradodecanuclear cubic framework, in whose cavity six n-butyl groups... |
29712254 | [12.12]Paracyclophanedodecaynes C<sub>36</sub> H<sub>8</sub> and C<sub>36</sub> Cl<sub>8</sub> : The Smallest Paracyclophynes and Their Transformation into the Carbon Cluster Ion C<sub>36</sub>. | The smallest [n.n]cyclophyne known, [12.12]paracyclophanedodecaynes C<sub>36</sub> H<sub>8</sub> and C<sub>36</sub> Cl<sub>8</sub> , were generated by [2+2] cycloreversion of its precursor under photolytic and mass spectrometric conditions. The stepwise loss of chlorine atoms from the anion of the octachloro derivative... |
29712243 | Polyphenylene Dendrimers as Sensitive and Selective Sensor Layers. | Rigid, dendritic poly(paraphenylene)s are excellently suited as sensitive and selective coatings for gravimetric sensors (quartz microbalances), since they incorporate guest molecules reversibly into their interior voids. The variety of their potential designs allows an optimal match of these multitalented hosts to the... |
29712114 | Cucurbit[n]uril Derivatives Soluble in Water and Organic Solvents. | Reminiscent of the ringed planet Saturn, new cucurbit[n]uril (CB[n]) derivatives CB*[5] and CB*[6] have rings decorating the "equator". The rings in this case are five- and six-fused cyclohexane rings, respectively (the structure of CB*[6] is shown). The remarkable solubility of the new CB[n] derivatives in water and o... |
29712109 | Nanoparticles, Proteins, and Nucleic Acids: Biotechnology Meets Materials Science. | Based on fundamental chemistry, biotechnology and materials science have developed over the past three decades into today's powerful disciplines which allow the engineering of advanced technical devices and the industrial production of active substances for pharmaceutical and biomedical applications. This review is foc... |
29712105 | Host-Guest Chemistry Aids and Abets a Stereospecific Photodimerization in the Solid State. | A bis(dialkylammonium ion)-substituted stilbene derivative cocrystallizes with bisparaphenylene[34]crown-10 to form, in the solid state, a 2:2 host-guest complex wherein the stilbene double bonds are aligned with a relative geometry suitable for a stereospecific photochemical [2+2] cycloaddition. When irradiated with w... |
29712104 | Calixarene-Porphyrin Supramolecular Complexes: pH-Tuning of the Complex Stoichiometry. | Self-aggregation of water-soluble pyridinium-substituted porphyrins with functionalized calixarenes leads to well-defined pH-tunable stoichiometries. Two assemblies with different porphyrin:calixarene ratios that crystallized at pH 2 and 6 have been structurally characterized. The Job plots of Soret band broadenings in... |
29712098 | Artificial Enzymes Formed through Directed Assembly of Molecular Square Encapsulated Epoxidation Catalysts. | Supramolecular complex formation imparts stability and substrate selectivity to a simple manganese-porphyrin-based epoxidation catalyst. Lewis acid/Lewis base directed assembly was used to encapsulate the epoxidation catalyst within a supramolecular square structure to form an enzyme-like catalyst system. The "molecula... |
29712096 | Organoclay Derivatives in the Synthesis of Macrocycles. | As an alternative to the rotaxane method, an organoclay can be used as a template for the efficient formation of macrocycles (ring in schematic representation) which are easily extracted from the clay interlayer space. The four-step synthesis involved preparation of a pillared clay from the dihydrochloride salt of p-xy... |
29712094 | Self-Assembly of a Mixed-Valence Copper(II)/Copper(III) Dithiocarbamate Catenane. | Chemical oxidation of two preformed dinuclear copper(II) dithiocarbamate macrocycles leads to the formation of a novel mixed-valence tetranuclear copper(II)/copper(III) dithiocarbamate [2]catenane in near quantitative yield. Structural (see X-ray crystal structure), magnetic susceptibility, electrospray mass spectromet... |
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