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21619189 | Selective vapor sorption by polymers and cavitands on acoustic wave sensors: is this molecular recognition? | Selectivity patterns for the sorption of organic vapors from the gas phase into cavitand monolayers on acoustic wave sensors are very similar to those seen for sorption of the same vapors by amorphous polymers, demonstrating that the vapor/cavitand selectivity patterns are determined primarily by solubility interaction... |
21619174 | Characterization of chiral host-guest complexation in fast atom bombardment mass spectrometry. | A new method has been developed for the characterization of complexion between host and guest molecules. Adduct formation between chiral crown ethers 1 and 2 and enantiomeric ammonium ions 4 and 5 was examined. The reference compound 3 (achiral host) was chosen to be similar in structure to the chiral crown ethers for ... |
16535265 | Enantioselective Metabolism of Chiral 3-Phenylbutyric Acid, an Intermediate of Linear Alkylbenzene Degradation, by Rhodococcus rhodochrous PB1. | Rhodococcus rhodochrous PB1 was isolated from compost soil by selective culture with racemic 3-phenylbutyric acid as the sole carbon and energy source. Growth experiments with the single pure enantiomers as well as with the racemate showed that only one of the two enantiomers, (R)-3-phenylbutyric acid, supported growth... |
11667049 | Synthesis and Evaluation of Thioether-Based Tris-Melamines as Components of Self-Assembled Aggregates Based on the CA.M Lattice. | Two new tris-melamine derivatives, triazine-thio-M(3) (5) (C(3)N(3)-2,4,6-[SCH(2)C(6)H(4)-3-N(CH(2)C(6)H(4)-4-C(CH(3))(3))COC(6)N(3)-2-NHC(3)N(3)(NH(2))(NHCH(2)CH(2)C(CH(3))(3))-5-Br](3)) and benzene-thio-M(3) (6) (C(6)H(3)-1,3,5-[SCH(2)C(6)H(4)-3-N(CH(2)C(6)H(4)-4-C(CH(3))(3))COC(6)H(3)-2-NHC(3)N(3)(NH(2))(NHCH(2)CH(2... |
11667033 | Synthetic Routes to a Constrained Ring Analog of Didemnin B. | The didemnin class of biologically active cyclodepsipeptides, isolated from a marine tunicate, has shown antitumor, antiviral, and immunosuppressive activities. Synthetic studies were undertaken to prepare a modified analog of one of the most potent congeners, didemnin B (1). The side chain of the isostatine unit was t... |
11666377 | Template Synthesis of a Tetraaza Macrocycle Which Involves Benzaldehyde Rather Than Formaldehyde as a Building Block. Isolation and Structure Determination of the Open-Chain Schiff Base Intermediate Complex. | The classical formaldehyde building block has been replaced by the bulkier benzaldehyde in the Cu(II) template synthesis of the cyclam-like tetraaza macrocycle of type 1, in which nitroethane operated as locking fragment. The synthetic pathway involves three distinct steps: (i) Schiff base condensation of the metal-fre... |
11666358 | Chiral, Three-Dimensional Supramolecular Compounds: Homo- and Bimetallic Oxalate- and 1,2-Dithiooxalate-Bridged Networks. A Structural and Photophysical Study. | In analogy to the [M(II)(bpy)(3)](2+) cations, where M(II) is a divalent transition-metal and bpy is 2,2'-bipyridine, the tris-chelated [M(III)(bpy)(3)](3+) cations, where M(III) is Cr(III) or Co(III), induce the crystallization of chiral, anionic three-dimensional (3D) coordination polymers of oxalate-bridged (&mgr;-o... |
9384754 | Capillary zone electrophoretic separation of C14-C18 linear saturated and unsaturated free fatty acids with indirect UV detection. | The baseline separation of eight saturated and unsaturated fatty acids of commercial interest was achieved in 15 min by counter-electroosmotic flow capillary zone electrophoresis (CZE), using dimethyl-beta-CD as a buffer additive. The background electrolyte consisted of 10 mM Tris-5 mM p-anisate (pH 8.1) and 1 mM dimet... |
9008937 | [Mechanisms and evaluation of multiple organ and system failure after trauma]. | Multiple organ failure (MOF) is a major cause of death of ICU trauma patients. Despite intensive clinical and experimental investigation, the exact physiopathology of this syndrome is unclear. Although diverse cellular and humoral mediators have been identified, their mechanistic role is still debated. In this article ... |
8807847 | Cooperativity and anti-cooperativity between ligand binding and the dimerization of ristocetin A: asymmetry of a homodimer complex and implications for signal transduction. | <h4>Background</h4>Recent work has indicated that dimerization is important in the mode of action of the vancomycin group of glycopeptide antibiotics. NMR studies have shown that one member of this group, ristocetin A, forms an asymmetric dimer with two physically different binding sites for cell wall peptides. Ligand ... |
9005655 | [The formation of supramolecular complexes as the pathway in the regulation of glycolytic enzyme activity]. | Information on the regulation of glycolytic enzyme properties by means of their reversible interaction with structural elements of the cell: myofibrillar and cytoskeletal proteins and with different kinds of membranes is generalized. The problem on the possible formation of complexes of glycolytic enzymes is discussed. |
8984903 | A novel synthesis method for cyclodextrins from maltose in water-organic solvent systems. | A novel enzymatic synthesis method of cyclodextrin (CD) from low-mol-wt maltose using cyclomaltodextrin glucanotransferase (CGTase) from Bacillus macerans has been developed in various water-organic solvent systems. A beta-CD was synthesized in a two-phase system consisting of water and cyclohexane. However, no CDs cou... |
8936347 | Adenosine receptor ligands: differences with acute versus chronic treatment. | Adenosine receptors have been the target of intense research with respect to potential use of selective ligands in a variety of therapeutic areas. Caffeine and theophylline are adenosine receptor antagonists, and over the past three decades a wide range of selective agonists and antagonists for adenosine receptor subty... |
8906989 | Assembly and immunogenicity of chimeric Gag-Env proteins derived from the human immunodeficiency virus type 1. | We evaluated the potential of the precursor Gag protein (Pr55) of the human immunodeficiency virus type 1 (HIV-1) as a carrier for the presentation of envelope epitopes. Recombinant chimeric core-envelope protein-expressing constructs were derived by deletion of regions within the gag gene, especially of regions encodi... |
8904231 | [Artificial models of transport proteins in membrane]. | Artificial molecules were designed to mimic membrane transport proteins which produce large and selective ion fluxes across biological membrane with functions of flux-control. Several amphiphilic lipid molecules were assembled in bilayer lipids to make supramolecular ion channels which gave single ion channel currents ... |
8901259 | AM1 calculations on inclusion complexes of cyclomaltoheptaose (beta-cyclodextrin) with 1,7-dioxaspiro[5.5]undecane and nonanal, and comparison with experimental results. | Semiempirical calculations on cyclomaltoheptaose (beta CD), 1,7-dioxaspiro[5.5]undecane (1), nonanal (2), and the inclusion complexes of beta CD with 1 and 2 were carried out using the AM1 method. The structure of beta CD after complete geometry optimization was in very good agreement with crystallographic structures. ... |
8900863 | Micellization and other associations of amphiphilic antimicrobial quaternary ammonium salts in aqueous solutions. | Micellization and other types of associations of amphiphilic quaternary ammonium salts (QAS) in aqueous solutions are analysed in connection with their cationic surfactant nature and antimicrobial activity. In homologous series of QAS, log CMC decreases linearly with the number of CH2 groups in the alkyl tail (tails) o... |
8900462 | Application of 2-hydroxypropyl-beta-cyclodextrin in the assay of acyl-CoA:cholesterol acyltransferase and neutral and acid cholesterol ester hydrolases. | The utility of 2-hydroxypropyl-beta-cyclodextrin for increasing the sensitivity of assays for the microsomal acylCoA:cholesterol acyltransferase, and the acid lysosomal and the neutral microsomal and cytosolic cholesterol ester hydrolase activity was studied in rat hepatocytes. Enzyme assays, at optimal concentrations ... |
8882623 | The binding characteristics of a human bladder recombinant P2X purinoceptor, labelled with [3H]-alpha beta meATP, [35S]-ATP gamma S or [33P]-ATP. | 1. The binding of [3H]-alpha beta meATP, [35s]-ATP gamma S and [alpha 33P]-ATP to a human bladder P2X purinoceptor, transiently expressed in CHO-K1 cells using the Semliki Forest Virus (SFV) expression system, was examined. The characteristics of the binding sites were compared with results obtained in rat vas deferens... |
8882455 | Possible enhancing mechanism of the cutaneous permeation of 4-biphenylylacetic acid by beta-cyclodextrin derivatives in hydrophilic ointment. | The enhancing effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the percutaneous absorption of 4-biphenylylacetic acid (BPAA), a nonsteroidal anti-inflammatory drug, in hydrophilic ointment were studied and compared with the parent beta-cyclodext... |
8882453 | Mechanism of inhibition of H+, K(+)-ATPase by sodium 2-[[4-(3- methoxypropoxy)-3-methylpyridin-2-yl]methylsulfinyl]-1H-benzimidazole (E3810). | Sodium 2-[[4-(3-methoxypropoxy)-3-methylpyridin-2-yl]methylsulfinyl ]- 1H-benzimidazole (E3810) and omeprazole inhibit gastric acid secretion through inhibition of the activity of H+, K(+)-ATPase present in parietal cell membrane vesicles, by chemical modification of SH groups in the enzyme molecule. In order to clarif... |
8881330 | Supramolecular cationic tetraruthenated porphyrin induces single-strand breaks and 8-oxo-7,8-dihydro-2'-deoxyguanosine formation in DNA in the presence of light. | The aim of this investigation is the evaluation of DNA interaction of with tetraruthenated porphyrin (TRP) and of DNA damage in the presence of light. Direct-fluorescence and electronic absorption measurements after incubation of DNA with TRP indicate strong binding between pBR322 DNA or calf thymus DNA with the modifi... |
8877813 | Inhibition of phosphatidylinositol-specific phospholipase C: studies on synthetic substrates, inhibitors and a synthetic enzyme. | Enzyme inhibition studies on phosphatidylinositol-specific phospholipase C (PI-PLC) from B. Cereus were performed in order to gain an understanding of the mechanism of the PI-PLC family of enzymes and to aid inhibitor design. Inhibition studies on two synthetic cyclic phosphonate analogues (1,2) of inositol cyclic-1:2-... |
8877812 | Design and analysis of RNA structure-specific agents as potential antivirals. | A number of pathogenic RNA viruses, such as HIV-1, have extensive folded RNA conformations with imperfect A-form duplexes that are essential for virus function, and could serve as targets for structure-specific antiviral drugs. A method for the discovery of such drugs involves evaluation of the interactions with RNA of... |
8877811 | Molecular docking towards drug discovery. | Fueled by advances in molecular structure determination, tools for structure-based drug design are proliferating rapidly. Lead discovery through searching of ligand databases with molecular docking techniques represents an attractive alternative to high-throughout random screening. The size of commercial databases impo... |
8877810 | Novel nonclassical inhibitors of glycinamide ribonucleotide formyltransferase: 10-formyl and 10-hydroxymethyl derivatives of 5,8,10-trideazapteroic acid. | Several new 10-formyl and 10-hydroxymethyl derivatives of 5,8,10-trideazapteroic acid have been synthesized by a novel and convenient enamine alkylation procedure. Two of these compounds (10a and 10b) were shown to be very powerful inhibitors of L. casei (10a, IC50 = 8 x 10(-6) M; 10b, IC50 = 7 x 10(-6) M) and recombin... |
8877809 | All D-amino acid hexapeptide inhibitors of melittin's cytolytic activity derived from synthetic combinatorial libraries. | The identification of peptides that inhibit the biological functions of proteins was used as a means to explore protein/ligand interactions involved in molecular recognition processes. This approach is based on the use of synthetic combinatorial libraries (SCLs) for the rapid identification of individual peptides that ... |
8877808 | Model systems for flavoenzyme activity. The effects of specific hydrogen bonds on the 13C and 1H NMR of flavins. | We have developed a family of receptors designed to bind flavin derivatives using specific hydrogen bond interactions. These synthetic host molecules provide a model for specific flavoenzyme-cofactor interactions, allowing isolation and observation of the effects of hydrogen bonding on flavin NMR. We describe here the ... |
8877807 | Molecular recognition with C-clamp porphyrins: synthesis, structural, and complexation studies. | Porphyrin-based molecular clefts equipped with a strategically positioned carboxylic group have been synthesized. These ditopic porphyrins exhibit excellent binding affinity for many neutral substrates. X-ray structures of a porphyrin-water inclusion complex and a Zn(porphyrin)-methanol complex reveal how the carboxyli... |
8877806 | Hydrophobic vs coulombic interactions in the binding of steroidal polyamines to DNA. | Seven new steroidal polyamines derived from bile acids, either lithocholic or deoxycholic acid, have been studied as DNA-binding agents using four complimentary methods: an ethidium displacement assay, observed changes in the thermal denaturation of poly[d(AT)], effects on hyperchromicity of DNA, and circular dichroism... |
8877805 | Inhibitors of HIV protease: unique non-peptide active site templates. | New templates were designed and prepared which straddle the active site of HIV-1 protease. These templates were designed to be "flexible scaffolds' upon which substituents could be appended to fill the pockets of HIV protease. The new templates prepared and analysed were 4-hydroxy-5H-furan-2-ones, 4-hydroxy-5,6-dihydro... |
8877804 | Molecular similarity analysis on biologically active macrocyclic bis(bibenzyls). | Conformational analysis of marchantin A (1), a bis(diarylether) type, and riccardin A (2), a diarylether-biphenyl type macrocyclic bis(bibenzyl) was carried out by systematic unbounded multiple minimum search (SUMM). Mobility of the macrocyclic rings was analysed by variable temperature 1H-NMR study. Molecular similari... |
8877803 | Experimental results from host-guest complexes for the design of effectors in biological systems and of enzyme analogous catalysts. | Strategies and results for the extraction of biologically important non-covalent binding increments from studies of synthetic host-guest complexes are described with selected examples. Systematic analyses of association constants and the corresponding complex conformation in solution allows us to assign specific values... |
8877802 | Comparative in vivo sensitizing efficacy of porphyrin and chlorin dimers joined with ester, ether, carbon-carbon or amide bonds. | The anti-cancer activity of dimers joined with ether, ester or carbon-carbon bonds by photodynamic therapy (PDT) was compared by using DBA/2 mice transplanted with SMT/F tumors. Dimers with ether and carbon-carbon linkages were found to be more effective than those linked with ester bonds. Variation of the substituents... |
8877801 | Seeing double: crystal structures of the type I TNF receptor. | The crystal structure of the extracellular domain of the type I tumor necrosis factor receptor (sTNF-R1) has been determined to 2.25 A at pH 7.5. We have also solved the structure of sTNF-R1 at pH 3.7. sTNF-R1 is an elongated molecule consisting of a linear combination of four cysteine-rich motifs. Interestingly, the c... |
8877800 | A technique to study molecular recognition in drug design: preliminary application of free energy derivatives to inhibition of a malarial cysteine protease. | We present molecular dynamics studies on model complexes of inhibitors of a malarial cysteine protease. The initial model for such complexes came from the model building of the protein using its homology with other cysteine proteases and calculations using DOCK to generate new lead compounds. Some of the initial model-... |
8877799 | A molecular dynamics study of the three-dimensional model of human synovial fluid phospholipase A2--transition state mimic complexes. | Different modes of binding of transition state mimics: amide, phosphonate and difluoro ketone, to human synovial fluid phospholipase A2 (HSF PLA2) are studies by molecular dynamics simulations computed in solvent. The results are analysed in the light of primary binding sites. Hydrogen bonding interaction plays an impo... |
8877798 | The "n' effect in molecular recognition. | The cooperativity which exists in crystal melting and many biological molecular recognition phenomena arises from extended arrays of weak interactions. We present a correlation between the melting temperature of a crystal and the intermolecular energy (which is evident only when compounds possessing several or many int... |
8877797 | Specific targeting of protein-DNA complexes by DNA-reactive drugs (+)-CC-1065 and pluramycins. | To gain insight into the interactions between transcriptional factor proteins and DNA, the DNA-reactive drugs (+)-CC-1065 and pluramycin were used to target specific protein-DNA complexes. The structural features of the complex between the transcriptional activator Sp1 and the 21-base-pair repeat of the early promoter ... |
8877796 | Molecular interaction analysis in ligand design using mass transport, kinetic and thermodynamic methods. | Ligand design in biotechnology is underpinned by the control of molecular affinity. Hence, measuring binding interactions is a key component in designing ligands for such uses as therapeutics, diagnostics, biomaterials and separation science. Mass transport, kinetic and thermodynamic methods have been used for macromol... |
8877795 | Molecular recognition by natural macrocycles. I. d-tubocurarine as a host molecule for organic anions. | The binding of 8-anilino-1-naphthalenesulfonate and 15 anions of substituted benzoic, aliphatic dicarboxylic, and N-acetyl-alpha-amino acids to a macrocyclic alkaloid d-tubocurarine in aqueous solution has been studied by fluorometry, conductometry, and 1H NMR. The binding constants vary from ca. 50 to 3300 M-1 dependi... |
8868478 | Synthesis, structure, and structure-activity relationships of divalent thrombin inhibitors containing an alpha-keto-amide transition-state mimetic. | A new class of divalent thrombin inhibitors is described that contains an alpha-keto-amide transition-state mimetic linking an active site binding group and a group that binds to the fibrinogen-binding exosite. The X-ray crystallographic structure of the most potent member of this new class, CVS995, shows many features... |
8868477 | A novel, multilayer structure of a helical peptide. | X-ray diffraction analysis at 1.5 A resolution has confirmed the helical conformation of a de novo designed 18-residue peptide. However, the crystal structure reveals the formation of continuous molecular layers of parallel-packed amphiphilic helices as a result of much more extensive helix-helix interactions than pred... |
8868051 | Assembly and suppression of endogenous Kv1.3 channels in human T cells. | The predominant K+ channel in human T lymphocytes is Kv1.3, which inactivates by a C-type mechanism. To study assembly of these tetrameric channels in Jurkat, a human T-lymphocyte cell line, we have characterized the formation of heterotetrameric channels between endogenous wild-type (WT) Kv1.3 subunits and heterologou... |
8868050 | Interaction of internal Ba2+ with a cloned Ca(2+)-dependent K+ (hslo) channel from smooth muscle. | We have studied potassium currents through a cloned Ca(2+)-dependent K+ channel (hslo) from human myometrium. Currents were recorded in inside-out macropatches from membranes of Xenopus laevis oocytes. In particular, the inactivation-like process that these channels show at high positive potentials was assessed in orde... |
8867442 | The effects of cross-link density and chemical exchange on magnetization transfer in polyacrylamide gels. | The effects of polymer structure and water-macromolecule interactions on proton relaxation in an aqueous model polymer have been investigated using quantitative measurements of magnetization transfer. Polyacrylamide gels composed of 95% water, 5% comonomers acrylamide and N,N'-methylene-bis-acrylamide were studied. The... |
8861644 | Identification of bovine viral diarrhea virus receptor in different cell types. | Anti-idiotypic antibodies (anti-ids) have been used successfully in studies on bovine viral diarrhea virus (BVDV) receptor(s) in our laboratory. The anti-ids specifically bound to cultured cells and identified a 50 kDa cellular membrane protein, which is thought to be a specific receptor for BVDV. In this study, flow c... |
9132094 | Evaluation of the effects of intravascular MR contrast media (gadolinium dendrimer) on 3D time of flight magnetic resonance angiography of the body. | The aims of this preliminary study were to establish the efficacy and minimum effective dose of TG(5)(FdDO3A)(52) gadolinium dendrimer for contrast-enhanced, three-dimensional (3D) time of flight (TOF) magnetic resonance angiography (MRA) of the body. In a dose ranging study in eight rabbits (Group A), each of two anim... |
8851567 | Susceptibility of melanized and nonmelanized Cryptococcus neoformans to the melanin-binding compounds trifluoperazine and chloroquine. | Cryptococcus neoformans is an opportunistic fungal pathogen which becomes heavily melanized in the presence of phenolic substrates such as L-dopa. Various drugs are known to bind to melanin with high affinity, including the antipsychotic agent trifluoperazine and the antimalarial agent chloroquine. We hypothesized that... |
8772643 | Antibody responses to macrocycles in lymphoma. | <h4>Unlabelled</h4>Metallic radioimmunoconjugates have promise for radioimmunoimaging and therapy. Macrocyclic chelating agents allow formation of stable metallic radioimmunoconjugates but have been reported to be immunogenic. This study assesses human antibody responses in patients that were imaged or treated with rad... |
8736496 | Engineering the aggregation properties of dodecameric glutamine synthetase: a single amino acid substitution controls 'salting out'. | Escherichia coli glutamine synthetase (GS) is a dodecamer of identical subunits which are arranged as two face-to-face hexameric rings. In the presence of 10% ammonium sulfate, wild type GS exhibits a pH-dependent "salting out' with a pKa of 4.51. Electron micrographs indicate that the pH-dependent aggregation correspo... |
8737051 | Modified beta-cyclodextrin (SBE7-beta-CyD) with viscous vehicle improves the ocular delivery and tolerability of pilocarpine prodrug in rabbits. | The complexation of pilocarpine prodrug, O,O'-dipropionyl-(1,4-xylylene) bispilocarpate, with various beta-cyclodextrin (beta-CyD) derivatives was studied by the phase solubility method. The effects of coadministered sulphobutyl ether beta-CyD (SBE7-beta-CyD) with and without poly(vinyl alcohol) (PVA) on the miotic res... |
8739608 | Antiviral activity of the bicyclam derivative JM3100 against drug-resistant strains of human immunodeficiency virus type 1. | Bicyclams have recently been identified as potent and selective inhibitors of human immunodeficiency virus type 1 (HIV-1) and type 2 (HIV-2) replication. The prototype of this series, JM3100 exhibits anti-HIV potency at concentrations ranging from 0.001 to 0.01 micrograms/ml. JM3100 proved to be active when tested agai... |
8739597 | Effects of SKF 108922, an HIV-1 protease inhibitor, on retrovirus replication in mice. | Rationally designed synthetic inhibitors of retroviral proteases inhibit the processing of viral polypeptides in cultures of human T lymphocytes infected with human immunodeficiency virus type 1 (HIV-1) and therefore suppress the infectivity of HIV-1 in vitro. We have previously reported the antiviral activity in vitro... |
8700911 | Z-membranes: artificial organelles for overexpressing recombinant integral membrane proteins. | We have expressed a fusion protein formed between the avian infectious bronchitis virus M protein and the bacterial enzyme beta-glucuronidase in transgenic tobacco cells. Electron microscope images of such cells demonstrate that overexpression of this fusion protein gives rise to a type of endoplasmic reticulum membran... |
8700877 | T-cell epitope analysis using subtracted expression libraries (TEASEL): application to a 38-kDA autoantigen recognized by T cells from an insulin-dependent diabetic patient. | Studies on circulating T cells and antibodies in newly diagnosed type 1 diabetic patients and rodent models of autoimmune diabetes suggest that beta-cell membrane proteins of 38 kDa may be important molecular targets of autoimmune attack. Biochemical approaches to the isolation and identification of the 38-kDa autoanti... |
8700831 | A quantitative test to estimate neutralizing antibodies to the hepatitis C virus: cytofluorimetric assessment of envelope glycoprotein 2 binding to target cells. | Hepatitis C virus (HCV) is a major cause of chronic hepatitis. The virus does not replicate efficiently in cell cultures, and it is therefore difficult to assess infection-neutralizing antibodies and to evaluate protective immunity in vitro. To study the binding of the HCV envelope to cell-surface receptors, we develop... |
8692733 | Evaluation of adjuvants that enhance the effectiveness of antisense oligodeoxynucleotides. | <h4>Purpose</h4>A factor limiting the effectiveness of antisense (AS) deoxyoligonucleotides (ODNs) is inefficient transport to their sites of action in the cytoplasm and in the nucleus. The extent of ODN transfer from endosomes to cytosol seems to be an important determinant of ODN effects. Consequently, the developmen... |
8704942 | Separation of testosterone metabolites in microsomal incubates using a new capillary electrophoresis assay. | A capillary electrophoresis method has been developed to separate the products of liver microsomal testosterone metabolism. The microsomal mixture undergoes liquid-liquid extraction and pre-concentration, and then electrophoretic analysis takes less than 25 min including capillary conditioning steps. The development of... |
8729936 | Somatotropin release-inhibiting factor and galanin innervation in the hypothalamus and pituitary of seabream (Sparus aurata). | The distribution of galanin (GAL) and somatotropin-release-inhibiting-factor (SRIF) immunoreactivity in the hypothalamus and pituitary of the sea bream (Sparus aurata) was studied by immunocytochemistry. An extensive system of neurons immunoreactive with antisera to the two peptides was identified throughout the brain ... |
8924735 | Boron trifluoride-etherate (Lewis acid) as an efficient acid at cyclization/cleavage reaction of D/L-amino acids affording the retention of their original configuration in the Edman sequencing method of peptides. | Boron trifluoride-etherate (BF3), one of the Lewis acids, was found to be an efficient acid in the Edman sequencing method, affording the retention of the N-terminal amino acid configuration at the cyclization/cleavage reaction from peptides. Examples for the sequencing of D-Leu-Gly and L-Pro-L-Leu are described, utili... |
8924734 | Reversed-phase chromatographic study of the binding of polychlorinated biphenyls to cyclodextrins and sodium dodecylsulphate. | The binding of polychlorinated biphenyls (PCBs) to hydroxypropyl-beta-cyclodextrin (HP-beta-CD), tau-cyclodextrin (tau-CD) and sodium dodecylsulphate (SDS) was studied by reversed-phase thin-layer chromatography and the relative strength of interaction was calculated. HP-beta-CD and SDS did not bind to PCBs making it u... |
8704107 | Tyrosine phosphorylation of focal adhesion kinase (p125FAK): regulation by cAMP and thrombin in mesangial cells. | Stress fibers, composed of actin filaments, converge upon and associate with a number of proteins, including focal adhesion kinase (p125FAK), and integrin receptors to form areas of close contact between cells and the extracellular matrix referred to as focal adhesions. Treatment of mesangial cells with cAMP-elevating ... |
8639493 | Structural and electronic properties of the heme cofactors in a multi-heme synthetic cytochrome. | Resonance Raman, absorption, and electron paramagnetic resonance spectra are reported for a water soluble, synthetic cytochrome. The protein is a variant of the cytochrome beta maquette described by Robertson et al. [Robertson, D. E., et al. (1995) Nature 368, 425-432] and is composed of 62 amino acid residues arranged... |
8639470 | Regulation of sterol 27-hydroxylase and an alternative pathway of bile acid biosynthesis in primary cultures of rat hepatocytes. | In man, hepatic mitochondrial sterol 27-hydroxylase and microsomal cholesterol 7alpha-hydroxylase initiate distinct pathways of bile acid biosynthesis from cholesterol, the "acidic" and "neutral" pathways, respectively. A similar acidic pathway in the rat has been hypothesized, but its quantitative importance and abili... |
8642258 | B lymphocytes secrete antigen-presenting vesicles. | Antigen-presenting cells contain a specialized late endocytic compartment, MIIC (major histocompatibility complex [MHC] class II-enriched compartment), that harbors newly synthesized MHC class II molecules in transit to the plasma membrane. MIICs have a limiting membrane enclosing characteristic internal membrane vesic... |
8785294 | Avidin-biotin interactions at vesicle surfaces: adsorption and binding, cross-bridge formation, and lateral interactions. | Densely packed domains of membrane proteins are important structures in cellular processes that involve ligand-receptor binding, receptor-mediated adhesion, and macromolecule aggregation. We have used the biotin-avidin interaction at lipid vesicle surfaces to mimic these processes, including the influence of a surface ... |
8785293 | Comparative effects of cholesterol and cholesterol sulfate on hydration and ordering of dimyristoylphosphatidylcholine membranes. | The comparative effect of cholesterol (CH) versus cholesterol sulfate (CS) on dimyristoylphosphatidylcholine (DMPC) membranes has been investigated by optical microscopy, freeze-fracture electron microscopy, x-ray diffraction, and solid state 2H and 31P nuclear magnetic resonance (NMR). The sulfate analogue extends the... |
8785279 | Theoretical study of the distal-side steric and electrostatic effects on the vibrational characteristics of the FeCO unit of the carbonylheme proteins and their models. | The vibronic theory of activation and quantum chemical intermediate neglect of differential overlap (INDO) calculations are used to study the activation of carbon monoxide (change of the C-O bond index and force field constant) by the imidazole complex with heme in dependence on the distortion of the porphyrin ring, ge... |
8785272 | Tryptophan dynamics of the FK506 binding protein: time-resolved fluorescence and simulations. | The FK506-binding protein (FKBP12) is important in the immunosuppressant action of FK506 and rapamycin. We have investigated Trp side chain dynamics in FKBP12, with and without a bound immunosuppressant, by measuring the Trp time-resolved fluorescence anisotropy decay r(t). The r(t) for W59 in aqueous uncomplexed FKBP1... |
8640842 | Human neutrophil interactions of a bispecific monoclonal antibody targeting tumor and human Fc gamma RIII. | 2B1 is a bispecific murine monoclonal antibody (bsmAb) targeting the c-erbB-2 and CD16 (Fc gamma RIII) antigens. c-erbB-2 is over-expressed by a variety of adenocarcinomas, and CD16, the low-affinity Fc gamma receptor for aggregated immunoglobulins, is expressed by polymorphonuclear leukocytes (PMN), natural killer (NK... |
8636147 | The sequence of the dictyostelium myo J heavy chain gene predicts a novel, dimeric, unconventional myosin with a heavy chain molecular mass of 258 kDa. | The complete sequence of the Dictyostelium myo J heavy chain gene has been determined from overlapping genomic clones. The gene spans approximately 7400 base pairs, is split by two small introns, and encodes a 2241-residue, 258-kDa heavy chain polypeptide that that is composed of an N-terminal 944-residue myosin head d... |
8621405 | Reduction in water activity greatly retards the phosphoryl transfer from ATP to enzyme protein in the catalytic cycle of sarcoplasmic reticulum Ca2+-ATPase. | Cys-674 of the sarcoplasmic reticulum Ca2+-ATPase was labeled with N-acetyl-N'-(5-sulfo-1-naphthyl)ethylenediamine without a loss of the catalytic activity. The ATP-induced drop in the fluorescence of the label, which was shown in our previous studies to reflect the conformational change upon formation of the calcium.e... |
8673236 | Effect of the degree of substitution of cyclodextrin derivatives on chiral separations by high-performance liquid chromatography and capillary electrophoresis. | Optical isomers of some basic racemic drugs (oxprenolol, AMEBD, ephedrine) were separated by high-performance liquid chromatography (HPLC) and/or capillary electrophoresis (CE) using carboxymethyl-beta-cyclodextrin (CMBCD) with various degree of substitution (DS). The effects of the separation conditions (pH, concentra... |
8673239 | Use of principal component analysis for the study of the retention behaviour of anticancer drugs on a beta-cyclodextrin polymer-coated silica column. | The retention parameters of eighteen commercial anticancer drugs were determined on a beta-cyclodextrin polymer-coated silica support (beta CDP) using methanol-water mixtures as eluent and the relationship between the retention behaviour and physico-chemical parameters was elucidated by principal component analysis (PC... |
8635479 | Recombination by resolvase to analyse DNA communications by the SfiI restriction endonuclease. | The SfiI endonuclease differs from other type II restriction enzymes by cleaving DNA concertedly at two copies of its recognition site, its optimal activity being with two sites on the same DNA molecule. The nature of this communication event between distant DNA sites was analysed on plasmids with recognition sites for... |
8631728 | The drug-binding activity of the multidrug-responding transcriptional regulator BmrR resides in its C-terminal domain. | Rhodamine and tetraphenylphosphonium, the substrates of the Bacillus subtilis multidrug efflux transporter Bmr, induce the expression of Bmr through direct interaction with its transcriptional activator BmrR. Here we show that the C-terminal domain of BmrR, expressed individually, binds both these compounds and therefo... |
8631722 | Binding and surface exposure characteristics of the gonococcal transferrin receptor are dependent on both transferrin-binding proteins. | Neisseria gonorrhoeae is capable of iron utilization from human transferrin in a receptor-mediated event. Transferrin-binding protein 1 (Tbp1) and Tbp2 have been implicated in transferrin receptor function, but their specific roles in transferrin binding and transferrin iron utilization have not yet been defined. We ut... |
8631720 | Plasmid RK2 toxin protein ParE: purification and interaction with the ParD antitoxin protein. | The parDE operon, located within the 3.2-kb stabilization region of plasmid RK2, encodes antitoxin (ParD) and toxin (ParE) proteins that stabilize the maintenance of this broad-host-range plasmid via a postsegregational killing mechanism. A ParE protein derivative, designated ParE', was purified by construction of a fu... |
8626298 | Characterization of the rcsA and rcsB genes from Salmonella typhi: rcsB through tviA is involved in regulation of Vi antigen synthesis. | Synthesis of Vi antigen, a capsular polysaccharide expressed by Salmonella typhi, is controlled by the viaA and viaB chromosomal loci. It was previously shown that Vi antigen expression was regulated by a system similar to the rcs regulatory system involved in colanic acid synthesis in Escherichia coli. We have cloned ... |
8626296 | The organization of the outside end of transposon Tn5. | The end sequences of the IS50 insertion sequence are known as the outside end (OE) and inside end. These complex ends are related but nonidentical 19-bp sequences that serve as substrates for the activity of the Tn5 transposase. Besides providing the binding site of the transposase, the end sequences of a transposon co... |
8626287 | Cyclization reaction catalyzed by branching enzyme. | The action of branching enzyme (EC 2.4.l.l8) from Bacillus stearothermophilus on amylose was analyzed. The enzyme reduced the molecular size of amylose without increasing the reducing power. This result could not be explained by the normal branching reaction model. When the product was treated with glucoamylase (an exo... |
8626279 | Cloning, sequencing, and expression of the gene encoding a large S-layer-associated endoxylanase from Thermoanaerobacterium sp. strain JW/SL-YS 485 in Escherichia coli. | The gene (xynA) encoding a surface-exposed, S-layer-associated endoxylanase from Thermoanaerobacterium sp. strain JW/SL-YS 485 was cloned and expressed in Escherichia coli. A 3.8-kb fragment was amplified from chromosomal DNA by using primers directed against conserved sequences of endoxylanases isolated from other the... |
8637858 | A few autoreactive cells in an autoimmune infiltrate control a vast population of nonspecific cells: a tale of smart bombs and the infantry. | Inflammatory infiltrates in tissue-specific autoimmune disease comprise a collection of T cells with specificity for an antigen in the target organ. These specific cells recruit a population of nonspecific T cells and macrophages. The rare tissue-specific T cells in the infiltrate have the capacity to regulate both the... |
8605172 | Cooperativity mutants of bacteriophage lambda cI repressor: temperature dependence of self-assembly. | Analytical ultracentrifugation was used to study higher order self-assembly of lambda cI repressors, including eight mutants whose monomer to dimer reactions were recently characterized [Burz et al. (1994) Biochemistry 33, 8399]. Six of the mutants were found to remain dimeric up to 50 microM total protein; the remaini... |
8627711 | Antibody cross-competition analysis of the human immunodeficiency virus type 1 gp120 exterior envelope glycoprotein. | Forty-six monoclonal antibodies (MAbs) able to bind to the native, monomeric gp120 glycoprotein of the human immunodeficiency virus type 1 (HIV-1) LAI (HXBc2) strain were used to generate a competition matrix. The data suggest the existence of two faces of the gp120 glycoprotein. The binding sites for the viral recepto... |
8627706 | Characterization of mutants of influenza A virus selected with the neuraminidase inhibitor 4-guanidino-Neu5Ac2en. | The development of viral resistance to the neuraminidase (NA) inhibitor, 4-guanidino-Neu5Ac2en, of influenza viruses was studied by serial passage of A/Turkey/Minnesota/833/80 (H4N2) in Madin-Darby canine kidney cells in the presence of increasing concentrations of inhibitor. Resistant mutants selected after eight pass... |
8627699 | Identification of a subdomain in the Moloney murine leukemia virus envelope protein involved in receptor binding. | We have mutated amino acids within the receptor-binding domain of Moloney murine leukemia virus envelope in order to identify residues involved in receptor binding. Analysis of mutations in the region of amino acids 81 to 88 indicates that this region is important for specific envelope-receptor interactions. None of th... |
8627686 | Molecular cloning and analysis of functional envelope genes from human immunodeficiency virus type 1 sequence subtypes A through G. The WHO and NIAID Networks for HIV Isolation and Characterization. | Present knowledge of human immunodeficiency virus type 1 (HIV-1) envelope immunobiology has been derived almost exclusively from analyses of subtype B viruses, yet such viruses represent only a minority of strains currently spreading worldwide. To generate a more representative panel of genetically diverse envelope gen... |
8627659 | The role of manganese in promoting multimerization and assembly of human immunodeficiency virus type 1 integrase as a catalytically active complex on immobilized long terminal repeat substrates. | The integration of a DNA copy of the viral genome into the genome of the host cell is an essential step in the replication of all retroviruses. Integration requires two discrete biochemical reactions; specific processing of each viral long terminal repeat terminus or donor substrate, and a DNA strand transfer step wher... |
8627651 | The receptor-binding domain of pseudorabies virus glycoprotein gC is composed of multiple discrete units that are functionally redundant. | Many herpesviruses attach to cells in a two-step process, using the glycoprotein gC family of homologs to bind the primary receptor, heparan sulfate (HS) proteoglycan, and glycoprotein gD homologs to bind an unknown secondary receptor. We have previously shown by deletion analysis that the amino-terminal one-third of g... |
8627650 | Molecular determinants of acute single-cell lysis by human immunodeficiency virus type 1. | Human immunodeficiency virus type 1 (HIV-1) infection of CD4-positive lymphocytes is accompanied by acute cytopathic effects, i.e., syncytium formation and single-cell lysis. Syncytium formation involves cell-cell fusion mediated by viral envelope glycoproteins on the surface of infected cells and by CD4 glycoproteins ... |
8641793 | Analysis of the superantigenic activity of mutant and allelic forms of streptococcal pyrogenic exotoxin A. | Infections with Streptococcus pyogenes (group A streptococcus) can result in the recently described streptococcal toxic shock syndrome (STSS), which is characterized by rashes, hypotension, multiorgan failure, and a high mortality rate. S. pyogenes isolates associated with STSS usually produce streptococcal pyrogenic e... |
8641785 | Characterization of two conformational epitopes of the Chlamydia trachomatis serovar L2 DnaK immunogen. | Chlamydia trachomatis DnaK is an important immunogen in chlamydial infections. DnaK is composed of a conserved N-terminal ATP-binding domain and a variable C-terminal peptide-binding domain. To locate the immunogenic part of C. trachomatis Dnak, we generated monoclonal antibodies (MAbs) against this protein. By use of ... |
8604334 | RNA aptamers that bind L-arginine with sub-micromolar dissociation constants and high enantioselectivity. | A completely randomized RNA pool as well as a degenerate pool comprised of an RNA sequence which binds citrulline with a dissociation constant of 0 muM were used to select for tight binding arginine specific RNA aptamers. A modified in vitro selection scheme, based on affinity chromatography was applied to allow the en... |
8605089 | In vivo fluorescence kinetics and localisation of aluminum phthalocyanine disulphonate in an autologous tumour model. | Sulphonated phthalocyanines are studied as photosensitizers for photodynamic therapy of cancer. Their strong fluorescence and tumour-localising properties make them also potentially useful for detection of cancer by fluorescence. For this purpose, we have studied the fluorescence kinetics and localisation of aluminum p... |
8605088 | Polyethylene glycol modification of a galactosylated streptavidin clearing agent: effects on immunogenicity and clearance of a biotinylated anti-tumour antibody. | Effective radioimmunotherapy is limited by slow antibody clearance from the circulation, which results in low tumour to blood ratios and restricts the dose of radiolabelled anti-tumour antibody that can be safely administrated. Avidin and streptavidin clearing agents have been shown to effectively complex and clear rad... |
8605087 | Preclinical in vivo efficacy of two 9-dihydrotaxane analogues against human and murine tumours. | Two 9-dihydrotaxane analogues were synthesised and tested for in vitro potency and in vivo efficacy against murine and human tumour xenografts in mice. The in vitro potency of 9-dihydrotaxol (9-DH-t) and 10-deacetyl-9-dihydrotaxol (10-DeAc-9-DH-t) was generally less than that of paclitaxel against human and murine tumo... |
8605888 | Xer-mediated site-specific recombination in vitro. | The Xer site-specific recombination system acts at ColE1 cer and pSC101 psi sites to ensure that these plasmids are in a monomeric state prior to cell division. We show that four proteins, ArgR, PepA, XerC and XerD are necessary and sufficient for recombination between directly repeated cer sites on a supercoiled plasm... |
8622668 | A discrete 3' region of U6 small nuclear RNA modulates the phosphorylation cycle of the C1 heterogeneous nuclear ribonucleoprotein particle protein. | The C heterogeneous ribonucleoprotein particle (hnRNP) protein bind to nascent pre-mRNA and may participate in assembly of the early prespliceosome. Ser/Thr phosphorylation of the C1 hnRNP protein in HeLa nuclear extracts regulates its binding to pre-mRNA (S. H. Mayrand, P. Dwen, and T. Pederson, Proc. Natl. Acad. Sci.... |
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