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1296157 | [Synthesis and supramolecular organization of components of the extracellular matrix by fibroblasts cultured in a collagen lattice]. | Fibroblasts cultured in a collagen gel contract and organize the gel into a three-dimensional matrix of collagen fibers. Within this matrix, the fibroblast cell cycle is blocked at the G1 phase but also at the G2 phase. The fibroblasts produce the main extracellular matrix components (collagen, noncollagen proteins, gl... |
1289493 | [Clinical formulations of amphotericin B]. | The clinical use of amphotericin B is impaired by its poor water solubility and by the severity of its side effects. Several amphotericin B formulations have already been prepared in an attempt to overcome these disadvantages. The following methods have been proposed to solubilize amphotericin B in water: the complexat... |
1369155 | Expression in E. coli and purification of intracellular proteins by fusion to cyclomaltodextrin glucanotransferase. | A plasmid expression vector was constructed to direct the synthesis of foreign proteins in Escherichia coli as fusions with cyclomaltodextrin glucanotransferase (CGT) with cytoplasmic location (delta ssCGT). The ability of CGT to bind to covalently immobilized cyclodextrins was utilized in purifying fused target protei... |
1494658 | [Comparative analysis of mechanisms of the modification of microorganism viability under the effect of UHF heating and hyperthermia]. | In experiments with models of isogenic Escherichia coli strains, a comparative study was made of the effect of SHF of electromagnetic field and hyperthermia. The survival rate of bacteria was determined and, simultaneously, injuries to genetic supramolecular structures were registered through measuring the anomalous ti... |
1491055 | Determination of D-alanine and D-glutamic acid in biological samples by coupled-column chromatography using beta-cyclodextrin as mobile phase additive. | A high-performance liquid chromatographic assay for monitoring traces of D-alanine and D-glutamic acid in peptide and protein hydrolysates is presented, which uses a two-column set-up with column switching. The main advantage of the proposed method is the higher reliability of the results, compared with the analysis by... |
1486859 | The third United States-Japan meeting on the Toxicological Characterization of Environmental Chemicals. | This report summarizes the discussion of the Third U.S.-Japan Meeting on the Toxicological Characterization of Environmental Chemicals held under the auspices of the U.S.-Japan cooperative in research and development in science and technology. Recent data on the interrelationships between toxicity, cell proliferation, ... |
1336723 | Integrated approach for evaluating species and interindividual differences in responsiveness to dioxins and structural analogs. | 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a ubiquitous environmental contaminant that is produced inadvertently during the synthesis of some organochlorine compounds, such as the chlorinated phenoxy pesticides. It is biologically and ecologically persistent, with an estimated half-life of 7 years in humans. It poss... |
1484238 | [An experimental study on elongation injury of peripheral nerve]. | The sciatic nerve of rabbits was indirectly elongated by lengthening the femur to clarify the pathology of elongation injury of the peripheral nerve. Electrophysiologic and morphologic changes and the blood flow in the nerve due to nerve elongation were evaluated in this model. No significant changes were observed when... |
1483085 | Adapting antibodies for clinical use. | Techniques for antibody engineering are now overcoming the problems that have prevented monoclonal antibodies being used routinely in clinical practice. With chemical and genetic manipulation antibodies can be linked to bacterial toxins, enzymes, radionuclides, or cytotoxic drugs, allowing targeting of treatment. Antig... |
1477928 | Enhancing effect of cyclodextrins on nasal absorption of insulin and its duration in rabbits. | The absorption of insulin (from porcine pancreas) in rabbits after the nasal administration of aqueous preparations containing insulin and five kinds of cyclodextrins (CyDs) in phosphate buffer solution at pH 7.0 was investigated. Without CyD, the insulin and glucose levels in plasma were unchanged, whereas a marked in... |
1477920 | Absorption enhancement of polypeptide drugs by cyclodextrins. I. Enhanced rectal absorption of insulin from hollow-type suppositories containing insulin and cyclodextrins in rabbits. | The absorption of insulin (from porcine pancreas) from the rectum of rabbits after the administration of hollow-type suppositories containing insulin and five kinds of cyclodextrins (CyDs) was investigated. Three types of suppositories were employed: suppository I containing insulin (approximately 26 IU/mg) and various... |
1477285 | Streptavidin binding to biotinylated lipid layers on solid supports. A neutron reflection and surface plasmon optical study. | Neutron reflection and surface plasmon optical experiments have been performed to evaluate structural data of the interfacial binding reaction between the protein streptavidin and a solid-supported lipid monolayer partly functionalized by biotin moieties. Since both experimental techniques operate in a total internal r... |
1477284 | Effect of the chirality of the glycerol backbone on the bilayer and nonbilayer phase transitions in the diastereomers of di-dodecyl-beta-D-glucopyranosyl glycerol. | We have studied the physical properties of aqueous dispersions of 1,2-sn- and 2,3-sn-didodecyl-beta-D-glucopyranosyl glycerols, as well as their diastereomeric mixture, using differential scanning calorimetry and low angle x-ray diffraction. Upon heating, both the chiral lipids and the diastereomeric mixture exhibit ch... |
1468632 | Germ line variable regions that match hypermutated sequences in genes encoding murine anti-hapten antibodies. | We asked whether there are germ line immunoglobulin variable (V) segments that match sites of hypermutation in V regions encoding murine antibodies. Murine germ line DNA was probed with a panel of short deoxyoligonucleotides identical in sequence to segments of hypermutated V regions from hybridomas generated in the BA... |
1467084 | Plasma lignocaine concentrations associated with extradural analgesia in patients with and without multiple organ failure. | We have measured plasma concentrations of lignocaine after thoracic extradural analgesia with continuous infusion of lignocaine in eight intensive care patients with chest wall trauma or after major upper abdominal surgery. Four patients developed multiple organ failure (MOF). Plasma concentrations of lignocaine in art... |
1463783 | Gene transfer into hepatocytes using asialoglycoprotein receptor mediated endocytosis of DNA complexed with an artificial tetra-antennary galactose ligand. | We have constructed an artificial ligand for the hepatocyte-specific asialoglycoprotein receptor for the purpose of generating a synthetic delivery system for DNA. This ligand has a tetra-antennary structure, containing four terminal galactose residues on a branched carrier peptide. The carbohydrate residues of this gl... |
1457829 | Genetic dissection of the signaling domain of a mammalian steroid receptor in yeast. | The mechanism of signal transduction by steroid receptor proteins is complex and not yet understood. We describe here a facile genetic strategy for dissection of the rat glucocorticoid receptor "signaling domain," a region of the protein that binds and transduces the hormonal signal. We found that the characteristics o... |
1454527 | Alteration by site-directed mutagenesis of the conserved lysine residue in the consensus ATP-binding sequence of the RecB protein of Escherichia coli. | The RecB and RecD subunits of the RecBCD enzyme of Escherichia coli contain amino acid sequences similar to a consensus mononucleotide binding motif found in a large number of other enzymes. We have constructed by site-directed mutagenesis a lysine-to-glutamine mutation in this sequence in the RecB protein. The mutant ... |
1447717 | Enhanced rectal absorption and reduced local irritation of the anti-inflammatory drug ethyl 4-biphenylylacetate in rats by complexation with water-soluble beta-cyclodextrin derivatives and formulation as oleaginous suppository. | To improve the rectal delivery of ethyl 4-biphenylylacetate (EBA), a prodrug of the anti-inflammatory drug 4-biphenylylacetic acid (BPAA), the use of highly water-soluble 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) and heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) was investigated and compared with the ... |
1445343 | Crystalline beta-cyclodextrin.12H2O reversibly dehydrates to beta-cyclodextrin.10.5 H2O under ambient conditions. | In contact with mother liquor, crystalline beta-cyclodextrin (beta-CD) hydrate has composition approximately beta-CD.12H2O. If crystals are dried at ambient conditions (18 degrees C, approximately 50% humidity), the unit cell volume diminishes approximately 30 to 50 A3. X-ray structure analysis of a dry crystal (0.89 A... |
1445269 | A recombinant hybrid anaphylatoxin with dual C3a/C5a activity. | By site-directed mutagenesis of a human complement factor C5a cDNA clone, we have designed a hybrid anaphylatoxin in which three amino acid residues in the C-terminal sequence of human C5a were exchanged to create the native C-terminal human C3a (hC3a) sequence Leu-Gly-Leu-Ala-Arg. This hybrid anaphylatoxin rC5a-(1-69)... |
1445261 | The binding of amide substrate analogues to phospholipase A2. Studies by 13C-nuclear-magnetic-resonance and infrared spectroscopy. | (R)-(2-dodecanamidoisohexyl)phosphocholine (DAHPC), labelled with 13C at the amide carbonyl group, has been synthesized and its binding to bovine pancreatic phospholipase A2 (PLA2) studied by n.m.r. and i.r. spectroscopy. Two-dimensional 1H-n.m.r. spectra show that, in the presence of Ca2+, DAHPC binds to the active si... |
1445256 | Molecular-dynamics investigation of molecular flexibility in ligand binding. | The molecular flexibility of an inhibitor in ligand-binding process has been investigated by the mass-weighted molecular-dynamics simulation, a computational method adopted from the standard molecular-dynamics simulation and one by which the conformational space of a biomolecular system over potential energy barriers c... |
1445247 | Evaluation of hydrogen-bonding and enantiomeric P2-S2 hydrophobic contacts in dynamic aspects of molecular recognition by papain. | 1. 2-(N'-Acetyl-D-phenylalanyl)hydroxyethyl 2'-pyridyl disulphide (compound IV) (m.p. 59 degrees C; [alpha]D20 -6.6 degrees (c 1.2 in methanol)) was synthesized. 2. The results of a study of the pH-dependence of the second-order rate constant (k) for its reaction with the catalytic-site thiol group (Cys-25) of papain (... |
1445246 | Characterization and purification of a novel dATP-binding protein in eukaryotes. | We characterized and purified an acidic dATP-binding protein, which, in its active form, resides in the nuclear fraction of a range of cells from mammals (including pig liver) and baker's yeast (Saccharomyces cerevisiae). This protein exhibits a high degree of specificity for the deoxy form of the naturally occurring n... |
1332681 | Characterization of mutant forms of the quinoprotein methanol dehydrogenase lacking an essential calcium ion. | Methanol dehydrogenase (MDH) from Methylobacterium extorquens, Methylophilus methylotrophus, Paracoccus denitrificans and Hyphomicrobium X all contained a single atom of Ca2+ per alpha 2 beta 2 tetramer. The role of Ca2+ was investigated using the MDH from Methylobacterium extorquens. This was shown to be similar to th... |
1359544 | NMR structure determination reveals that the homeodomain is connected through a flexible linker to the main body in the Drosophila Antennapedia protein. | The secondary structure of an N-terminally elongated Antennapedia (Antp) homeodomain (HD) polypeptide containing residues -14 to 67, where residues 1-60 constitute the HD, has been determined by NMR in solution. This polypeptide contains the conserved motif -Tyr-Pro-Trp-Met- (YPWM) at positions -9 to -6. Despite the hy... |
1438240 | Analogs of palmitoyl-CoA that are substrates for myristoyl-CoA:protein N-myristoyltransferase. | Saccharomyces cerevisiae myristoyl-CoA:protein N-myristoyltransferase (Nmt1p; EC 2.3.1.97) is an essential enzyme that is highly selective for myristoyl-CoA in vivo. It is unclear why myristate (C14:0), a rare cellular fatty acid, has been selected for this covalent protein modification over more abundant fatty acids s... |
1438214 | Anthrax toxin protective antigen is activated by a cell surface protease with the sequence specificity and catalytic properties of furin. | Proteolytic cleavage of the protective antigen (PA) protein of anthrax toxin at residues 164-167 is necessary for toxic activity. Cleavage by a cellular protease at this sequence, Arg-Lys-Lys-Arg, normally follows binding of PA to a cell surface receptor. We attempted to identify this protease by determining its sequen... |
1279672 | Human monoclonal Fab fragments derived from a combinatorial library bind to respiratory syncytial virus F glycoprotein and neutralize infectivity. | Respiratory syncytial virus (RSV) is the most important cause, throughout the world, of severe viral lower respiratory tract illness in young children. Antibodies are known to mediate resistance to RSV infection and illness. We have isolated a number of human monoclonal Fab fragments to RSV F glycoprotein from a combin... |
1279671 | Identification of a previously unknown human collagen chain, alpha 1(XV), characterized by extensive interruptions in the triple-helical region. | A previously unknown collagen cDNA clone, PF19, was isolated from a human placenta library. The 2.1-kilobase insert has a complete open reading frame of 709 amino acids that includes 12 amino acids of the NH2-terminal domain, a principally collagenous region of 577 residues, and 120 residues of the noncollagenous COOH ... |
1438203 | Structure of the ColE1 DNA molecule before segregation to daughter molecules. | The segregation of daughter DNA molecules at the end stage of replication of plasmid ColE1 was examined. When circular ColE1 DNA replicates in a cell extract at a high KCl concentration (140 mM), a unique class of molecules accumulates. When the molecule is cleaved by a restriction enzyme that cuts the ColE1 DNA at a s... |
1332027 | Extended x-ray absorption fine structure studies of a retrovirus: equine infectious anemia virus cysteine arrays are coordinated to zinc. | Zinc finger arrays have been established as a critical structural feature of proteins involved in DNA recognition. Retroviral nucleocapsid proteins, which are involved in the binding of viral RNA, contain conserved cysteine-rich arrays that have been suggested to coordinate zinc. We provide metalloprotein structural da... |
1438192 | A binary plasmid system for shuffling combinatorial antibody libraries. | We have used a binary system of replicon-compatible plasmids to test the potential for promiscuous recombination of heavy and light chains within sets of human Fab fragments isolated from combinatorial antibody libraries. Antibody molecules showed a surprising amount of promiscuity in that a particular heavy chain coul... |
1385475 | Epitope regions on U1 small nuclear RNA recognized by anti-U1RNA-specific autoantibodies. | Autoantibodies specifically directed to U1RNA were found in patients suffering from systemic lupus erythematosus (SLE) overlap syndromes. To obtain more insight in the mechanism responsible for this U1RNA-specific antibody formation and to use the antibodies eventually as a tool to study U1RNA-protein (U1RNP) interacti... |
1385448 | Endothelial cells interact with the core protein of basement membrane perlecan through beta 1 and beta 3 integrins: an adhesion modulated by glycosaminoglycan. | Aortic endothelial cells adhere to the core protein of murine perlecan, a heparan sulfate proteoglycan present in endothelial basement membrane. We found that cell adhesion was partially inhibited by beta 1 integrin-specific mAb and almost completely blocked by a mixture of beta 1 and alpha v beta 3 antibodies. Further... |
1429841 | Newly assembled microtubules are concentrated in the proximal and distal regions of growing axons. | We have investigated the sites of microtubule (MT) assembly in neurons during axon growth by taking advantage of the relationship between the proportion of tyrosinated alpha-tubulin (tyr-tubulin) in MTs and their age. Specifically, young (newly assembled) MTs contain more tyr-tubulin than older (more long-lived) MTs. T... |
1429656 | Opposed actions of regulatory proteins, DnaA and IciA, in opening the replication origin of Escherichia coli. | The opening of the three tandem 13-mers (iterons) in the replication origin (oriC) of Escherichia coli by DnaA protein, assisted by protein HU or IHF (Hwang, D. S., and Kornberg, A. (1992) J. Biol. Chem. 267, 23083-23086), represents an essential early stage in the initiation of chromosomal replication (Bramhill, D., a... |
1331049 | Polymerization of pNcollagen I and copolymerization of pNcollagen I with collagen I. A kinetic, thermodynamic, and morphologic study. | Previous observations established that pNcollagen III copolymerized with collagen I and decreased the diameter of the fibrils formed (Romanic, A.M., Adachi, E., Kadler, K.E., Hojima, Y., and Prockop, D.J. (1991) J. Biol. Chem. 266, 12703-12709). Here, procollagen I alone or mixtures of procollagen I and pCcollagen I we... |
1385394 | Catalytic properties of the cloned amylase from Bacillus licheniformis. | A gene encoding a new amylolytic enzyme of Bacillus licheniformis (BLMA) has been cloned, and we characterized the enzyme expressed in Escherichia coli. The genomic DNA of B. licheniformis was double-digested with EcoRI and BamHI and ligated the pBR322. The transformed E. coli was selected by its amylolytic activity, w... |
1429554 | The stereospecific interaction between chlorophylls and chlorophyllase. Possible implication for chlorophyll biosynthesis and degradation. | Chlorophyllase-catalyzed hydrolysis and esterification of chlorophylls, bacteriochlorophylls, and their free acids, respectively, depend on the configuration around the C-13(2) atom of the corresponding substrate. The data suggest that the enzyme interacts preferentially with compounds having the isocyclic carbomethoxy... |
1429471 | Analysis of mutations in cyclodextrin glucanotransferase from Bacillus stearothermophilus which affect cyclization characteristics and thermostability. | Cyclodextrin glucanotransferase (CGTase; EC 2.4.1.19) produces cyclodextrin from starch. The CGTase molecule is composed of four globular domains, A, B, C, and D. In order to gain better understanding of the amylolytic and cyclization mechanisms of CGTase, mutant CGTases were constructed from a CGTase gene (cgt1) of Ba... |
1429466 | Assay, purification, and characterization of cobaltochelatase, a unique complex enzyme catalyzing cobalt insertion in hydrogenobyrinic acid a,c-diamide during coenzyme B12 biosynthesis in Pseudomonas denitrificans. | Hydrogenobyrinic acid a,c-diamide was shown to be the substrate of cobaltochelatase, an enzyme that catalyzes cobalt insertion in the corrin ring during the biosynthesis of coenzyme B12 in Pseudomonas denitrificans. Cobaltochelatase was demonstrated to be a complex enzyme composed of two different components of M(r) 14... |
1428916 | Photoreactive 111In-cyclodextrin inclusion complex: a new heterobifunctional reagent for antibody labeling. | The compound of interest, N-5-azido-2-nitrobenzoylaminomethyl-111In-acetylacetone-alpha-cycl odextrin (CD) (V) was synthesized by the selective tosylation of alpha-CD to form 6-tosyl-6-deoxy-CD, which was then reacted with NaN3 to form 6-azido-6-deoxy-CD (II). This was followed by catalytic hydrogenation to yield III. ... |
1330327 | The capture of a DNA double helix by an ATP-dependent protein clamp: a key step in DNA transport by type II DNA topoisomerases. | The binding of linear and circular forms of DNA to yeast DNA topoisomerase II or its complex with AMPPNP, the nonhydrolyzable beta,gamma-imido analog of ATP, was carried out to probe the ATP analog-induced conformational change of the enzyme. Binding of the ATP analog is shown to convert the enzyme to a circular clamp ... |
1420180 | Laminins and other strange proteins. | Laminins are large multidomain proteins of the extracellular matrix (ECM) with important functions in the development and maintenance of cellular organization and supramolecular structure, in particular in basement membranes. Each molecule is composed of three polypeptide chains, A (300-400 kDa) and B1 and B2 (180-200 ... |
1416119 | Effects of halothane and quinidine on intracardiac conduction and QTc interval in pentobarbital-anesthetized dogs. | To confirm in vitro data that halothane and quinidine depressed cardiac conduction and prolonged action potential (AP) duration, the electrocardiogram and His bundle electrogram were recorded in dogs during basal pentobarbital anesthesia, after 1% halothane or quinidine (2.38 +/- 0.22 micrograms/mL serum concentration ... |
1406672 | Functional interference between the ubiquitous and constitutive octamer transcription factor 1 (OTF-1) and the glucocorticoid receptor by direct protein-protein interaction involving the homeo subdomain of OTF-1. | The ubiquitous and constitutive octamer transcription factor OTF-1 (Oct 1) is the target of positive regulation by the potent herpes simplex virus trans-activator VP16, which forms a complex with the homeodomain of OTF-1. Here we present evidence that the glucocorticoid receptor can negatively regulate OTF-1 function b... |
1383569 | Design of high-affinity major histocompatibility complex-specific antagonist peptides that inhibit cytotoxic T-lymphocyte activity: implications for control of viral disease. | Cytotoxic T lymphocytes (CTLs) recognize viral antigens presented by infected cells in the context of their major histocompatibility complex glycoproteins. The irreversible killing of virus-infected cells by virus-specific CTLs can be the cause of serious disease, particularly in the central nervous, hepatic, and cardi... |
1404608 | Oligomerization of hepatitis delta antigen is required for both the trans-activating and trans-dominant inhibitory activities of the delta antigen. | Two forms of hepatitis delta antigen (HDAg) have different roles in the replication cycle of hepatitis delta virus (HDV); the small forms trans activates HDV RNA replication, whereas the large form suppresses it but is needed for virion assembly. To understand the mechanism of these regulatory activities, we studied th... |
1404607 | Fusion mutants of Newcastle disease virus selected with monoclonal antibodies to the hemagglutinin-neuraminidase. | The Australia-Victoria (AV) isolate of Newcastle disease virus (NDV) induces fusion from within but not fusion from without. L1, a neuraminidase (NA)-deficient virus derived from AV, has the opposite fusion phenotype from the wild-type virus. It fails to induce the former mode of fusion, but has gained a limited abilit... |
1328679 | Expression, self-assembly, and antigenicity of the Norwalk virus capsid protein. | Norwalk virus capsid protein was produced by expression of the second and third open reading frames of the Norwalk virus genome, using a cell-free translation system and baculovirus recombinants. Analysis of the expressed products showed that the second open reading frame encodes a protein with an apparent molecular we... |
1328670 | Characterization of nuclear proteins that bind the EFII enhancer sequence in the Rous sarcoma virus long terminal repeat. | The EFII cis element is a 38-bp sequence at the 5' end of the Rous sarcoma virus long terminal repeat, extending from nucleotides -229 to -192 (with respect to the viral transcription start site), which is recognized by sequence-specific DNA-binding proteins in avian fibroblast nuclear extracts (L. Sealy and R. Chalkle... |
1402673 | Antivirally protective cytotoxic T cell memory to lymphocytic choriomeningitis virus is governed by persisting antigen. | The basis of antiviral protection by memory cytotoxic T lymphocytes (CTL) was investigated in vivo and in vitro using lymphocytic choriomeningitis virus (LCMV) and recombinant vaccinia viruses expressing the LCMV-glycoprotein (vacc-GP) or -nucleoprotein (vacc-NP). The widely replicating LCMV with a tendency to persist ... |
1400241 | Function of the N-terminal half of RepA in activation of Rts1 ori. | The RepA protein of the Rts1 plasmid, consisting of 288 amino acids, is a trans-acting protein essential for replication. A mutant repA gene, repA delta C143, carrying a deletion that removed the 143 C-terminal amino acids of RepA, could transform, but at a low frequency, an Escherichia coli polA strain, JG112, when re... |
1383159 | Characterization of cell wall proteins from yeast and mycelial cells of Candida albicans by labelling with biotin: comparison with other techniques. | Candida albicans ATCC 26555 blastoconidia and blastoconidia bearing germ tubes were metabolically labelled by incubating the cells with 14C-labelled protein hydrolysate and were subsequently tagged with biotin. Double-labelled (radioactive and biotinylated) cell wall proteins and glycoproteins were extracted from intac... |
1398984 | Ability of Proteus mirabilis to invade human urothelial cells is coupled to motility and swarming differentiation. | Proteus mirabilis causes serious kidney infections which can involve invasion of host urothelial cells. We present data showing that the ability to invade host urothelial cells is closely coupled to swarming, a form of cyclical multicellular behavior in which vegetative bacteria differentiate into hyperflagellated, fil... |
1398975 | Interaction of the fish pathogen Aeromonas salmonicida with rainbow trout macrophages. | A procedure was developed to culture rainbow trout macrophages (M phi) on supported glass coverslips. Using this method and a variety of well-characterized Aeromonas salmonicida strains with normal or altered cell surfaces, we investigated the role of this unusual bacterial surface in the bacterium-M phi interaction. A... |
1398968 | Proliferative responses and gamma interferon and tumor necrosis factor production by lymphocytes isolated from tracheobroncheal lymph nodes and spleen of mice aerosol infected with Bordetella pertussis. | A group of mice was aerosol infected with live, virulent Bordetella pertussis bacteria. During a period of 7 weeks following the infection, with intervals of 1 week, lymphocytes were isolated from the tracheobroncheal lymph nodes (TBL) and the spleens (SPL) of the infected mice. The in vitro proliferative responses as ... |
1398959 | Mycobacterium leprae produces extracellular homologs of the antigen 85 complex. | The antigen 85 complex is a set of at least three closely related secreted proteins (85A, 85B, and 85C) of 30 to 32 kDa produced by Mycobacterium tuberculosis and other mycobacteria. Their prominence in Mycobacterium leprae, the one obligate intracellular pathogen of the genus, had been assumed on the basis of immunolo... |
1327755 | The inner nuclear membrane protein p58 associates in vivo with a p58 kinase and the nuclear lamins. | p58, also referred to as the lamin B receptor, is an intrinsic protein of the inner nuclear membrane that binds in vitro to lamin B. Previous studies have demonstrated that p58 is phosphorylated in vivo and removal of its phosphate moieties affects lamin B binding. Using affinity-purified antipeptide antibodies, we hav... |
1396586 | Crystal structure of human platelet-derived growth factor BB. | The crystal structure of the homodimeric BB isoform of human recombinant platelet-derived growth factor (PDGF-BB) has been determined by X-ray analysis to 3.0 A resolution. The polypeptide chain is folded into two highly twisted antiparallel pairs of beta-strands and contains an unusual knotted arrangement of three int... |
1396575 | The cooperative binding of fructose-1,6-bisphosphate to yeast pyruvate kinase. | The cooperative binding of the allosteric activator fructose-1,6-bisphosphate [Fru(1,6)P2] to yeast pyruvate kinase was investigated by equilibrium dialysis and fluorescence quench titration. The results show that yeast pyruvate kinase binds four molecules of Fru(1,6)P2 per tetramer and the observed fluorescence quench... |
19431860 | Unique biphasic band shape of the visible circular dichroism of bacteriorhodopsin in purple membrane: Excitons, multiple transitions or protein heterogeneity? | OVER A DECADE AND A HALF AGO, WHEN THE FIRST VISIBLE MEMBRANE SUSPENSION CIRCULAR DICHROIC (CD) SPECTRUM OF THE PURPLE MEMBRANE (PM) WAS PRESENTED, TWO MECHANISMS WERE PROPOSED TO ACCOUNT FOR THE OBSERVED BIPHASIC SHAPED CD BAND: (a) excitonic interactions among the retinals of the sole protein bacteriorhodopsin (bR) i... |
19431854 | Effect of coat protein mutations in bacteriophage fd studied by sedimentation analysis. | (a) Bacteriophage fd is a filamentous virus that has previously been well characterized. (b) Earlier work using point mutagenesis indicated that a lysine residue at position 48 in the major coat protein plays a crucial role in interacting with the DNA and governing the assembly into an intact virion. (c) In this study ... |
18965568 | Calixarene-based potentiometric ion-selective electrodes for silver. | Four lipophilic sulphur and/or nitrogen containing calixarene derivatives have been tested as ionophores in Ag(I)-selective poly (vinyl chloride) membrane electrodes. All gave acceptable linear responses with one giving a response of 50 mV/dec in the Ag(I) ion activity range 10(-4)-10(-1)M and high selectivity towards ... |
1341183 | [Prolonged mechanical ventilation following heart surgery]. | <h4>Purpose</h4>To study the causes of difficulty or impossible weaning of cardiac surgical patients undergoing mechanical ventilation in the postoperative period and their outcome.<h4>Methods</h4>Three hundred and forty three consecutive adult patients submitted to open heart surgery were retrospectively studied and c... |
1284654 | Antigen-antibody interactions: elucidation of the epitope and strain-specificity of a monoclonal antibody directed against the pilin protein adherence binding domain of Pseudomonas aeruginosa strain K. | The C-terminal region of Pseudomonas aeruginosa strain K (PAK) pilin comprises both an epitope for the strain-specific monoclonal antibody PK99H, which blocks pilus-mediated adherence, and the adherence binding domain for buccal and tracheal epithelial cells. The PK99H epitope was located in sequence 134-140 (Asp-Glu-G... |
1363689 | Evaluation of six chiral stationary phases in LC for their selectivity towards drug enantiomers. | Six chiral stationary phases (CSP) were evaluated for their enantioselectivity towards a series of 45 drugs with different acidic, basic or neutral properties. These CSPs were: a polyacrylamide phase, Chiraspher; two polysaccharide-based phases, cellulose tris-3,5-dimethyl phenylcarbamate (Chiralcel OD) and the S-napht... |
1298387 | Fluorescence enhancement of two terpenes commonly present in essential oils. | The fluorescence spectra of anethole and eugenol dissolved in methanol-aqueous binary systems with the addition of alpha- and beta-cyclodextrin were studied. Observed enhancement of the fluorescence intensity is possibly due to the higher quantum yield of the cyclodextrin-hydrocarbon inclusion complexes. The measured f... |
1298374 | The determination of the geometric isomers and related impurities of dothiepin in a pharmaceutical preparation by capillary electrophoresis. | The application of capillary zone electrophoresis in the assay of the tricyclic antidepressant drug, dothiepin, in tablets is discussed. The method developed for dothiepin which exists as the cis- and trans-isomers and contains two major related impurities, an 11-oxo compound and a propanamine, utilizes inclusion compl... |
1298372 | Selectivity manipulation in micellar electrokinetic chromatography. | Micellar electrokinetic chromatography (MEKC) permits the separation of electrically neutral analytes by chromatographic principles in a capillary electrophoresis system. The most effective way to obtain high resolution in MEKC is to increase the separation factor, as in conventional chromatography. The separation fact... |
1297350 | Intermediate filament proteins: many unanswered questions, few unquestioned answers. | Major constituents of the cytoskeleton and the nuclear matrix, cytoplasmic intermediate filament subunits and nuclear lamins belong to a multigene family of proteins whose function is poorly understood. It has now become a general contention that important clues to the physiological roles of these proteins may reside i... |
1295869 | In vivo interaction of cationised ferritin with the surface coat and endocytosis by pulmonary intravascular macrophages: a tracer kinetic study. | The pulmonary intravascular macrophages (PIMs) of goat lung contain a unique electron-dense coat consisting of globular units arranged in a linear fashion along the cell surface. The globules showed a high affinity for cationised ferritin (CF) within 2-5 min of its intravenous injection, whereas native ferritin did not... |
1491098 | Characterization of bacterial growth on solid medium with image analysis. | Alkaliphilic bacterial strains producing the enzyme cyclodextrin glucanotransferase were cultivated on solid agar medium containing an indicator system detecting the enzyme. The growth of the colony and the surrounding diffusion zone, due to the enzyme, were measured by the image analysis during the cultivation. It was... |
1491009 | Three-dimensional structure of soybean beta-amylase determined at 3.0 A resolution: preliminary chain tracing of the complex with alpha-cyclodextrin. | The three-dimensional structure of a complex of soybean beta-amylase [EC 3.2.1.2] with an inhibitor, alpha-cyclodextrin, has been determined at 3.0 A resolution by X-ray diffraction analysis. Preliminary chain tracing showed that the enzyme folded into large and small domains. The large domain has a (beta alpha)8 super... |
1369056 | Enzymatic synthesis of 2-chloro-4-nitrophenyl 4,6-O-3-ketobutylidene beta-maltopentaoside, a substrate for alpha-amylase. | A transglycosylation reaction with 2-chloro-4-nitrophenyl beta-maltoside as an acceptor was done with 4,6-O-3-ketobutylidene maltopentaose and Bacillus macerans cyclodextrin glucanotransferase in an aqueous solution containing 50% n-propanol, and there were two main transglycosylation products. They were identified as ... |
1334203 | Nuclear magnetic relaxation dispersion profiles of aqueous solutions of a series of Gd(NOTA) analogs. | Nuclear magnetic relaxation dispersion (NMRD) profiles and ESR linewidths have been measured for a series of neutral Gd(3+)-triazamacrocyclic complexes and compared with previous data for the simplest member of the macrocyclic triaza series, Gd(NOTA), and for the widely studied linear triaza complex, Gd(DTPA)2-. Water ... |
1452629 | Efficient enantioselective separation and determination of trace impurities in secondary amino acids (i.e., imino acids). | An R-(-)-1-(1-naphthyl)ethyl carbamoylated-beta-cyclodextrin bonded phase in conjunction with a nonaqueous polar mobile phase was used for the highly selective enantioseparation of a number of secondary amino acids after their pre-column derivatization with 9-fluorenylmethyl chloroformate (FMOC). Under the conditions e... |
1447399 | Mirror images: the analysis of pharmaceutical enantiomers. | Pharmaceutical enantiomers often exhibit different pharmacodynamic and pharmacokinetic properties. Stereospecific chromatographic assays are available to separate these stereoisomers. Therapeutic agents often contain chemical functional groups (e.g. amino, hydroxyl, carbonyl, and carboxylic acid). These can be reacted ... |
1332674 | Spectroscopic identification of the haem axial ligands of haemoferritin and location of possible haem-binding sites in ferritin by molecular modelling. | Horse spleen ferritin will bind up to 16 protoporphyrin IX haem groups per 24 subunits in vitro [Kadir & Moore (1990) FEBS Lett. 276, 81-84] at a site that causes the haem to be low spin for both ferric and ferrous states. E.p.r. spectra at 10 K of the oxidized form of the resulting haemoferritin gives g values of 2.93... |
1279521 | Temperature-dependent template switching during in vitro cDNA synthesis by the AMV-reverse transcriptase. | Reverse transcriptase template switching has been invoked to explain several aspects of retroviral replication and recombination, and has been reported in vitro for the Moloney murine leukemia virus (M-MuLV) reverse transcriptase. During in vitro cDNA synthesis, the avian myeloblastosis virus (AMV) reverse transcriptas... |
1436040 | Crystal structure of a streptococcal protein G domain bound to an Fab fragment. | Protein G is a cell-surface protein from Streptococcus which binds to IgG molecules from a wide range of species with an affinity comparable to that of antigen. The high affinity of protein G for the Fab portion of IgG poses a particular challenge in molecular recognition, given the variability of heavy chain subclass,... |
1330320 | The role of topoisomerase IV in partitioning bacterial replicons and the structure of catenated intermediates in DNA replication. | Mutants in bacterial topoisomerase (topo) IV are deficient in chromosomal partitioning. To investigate the basis of this phenotype, we examined plasmid DNA topology in conditionally lethal topo IV mutants. We found that dimeric catenated plasmids accumulated in vivo after topo IV inhibition. The catenanes were supercoi... |
1421572 | Role of GTP hydrolysis in microtubule dynamics: information from a slowly hydrolyzable analogue, GMPCPP. | The role of GTP hydrolysis in microtubule dynamics has been reinvestigated using an analogue of GTP, guanylyl-(alpha, beta)-methylene-diphosphonate (GMPCPP). This analogue binds to the tubulin exchangeable nucleotide binding site (E-site) with an affinity four to eightfold lower than GTP and promotes the polymerization... |
1421571 | Modulation of the dynamic instability of tubulin assembly by the microtubule-associated protein tau. | Microtubule-associated proteins (MAP), such as tau, modulate the extent and rate of microtubule assembly and play an essential role in morphogenetic processes, such as axonal growth. We have examined the mechanism by which tau affects microtubule polymerization by examining the kinetics of microtubule assembly and disa... |
1384743 | Ion channels in icosahedral virus: a comparative analysis of the structures and binding sites at their fivefold axes. | An analysis of the crystallographically determined structures of the icosahedral protein coats of Tomato Bushy Stunt Virus, Southern Bean Mosaic Virus, Satellite Tobacco Necrosis Virus, Human Rhinovirus 14 and Mengovirus around their fivefold axes is presented. Accessibilities surfaces, electrostatic energy profile cal... |
1420928 | Confinement as a determinant of macromolecular structure and reactivity. | The confinement of macromolecules within enclosures or "pores" of comparable dimensions results in significant size- and shape-dependent alterations of macromolecular chemical potential and reactivity. Calculations of the magnitude of this effect for model particles of different shapes in model enclosures of different ... |
1417785 | Analysis and elimination of protein perturbation in infrared difference spectra of acyl-chymotrypsin ester carbonyl groups by using 13C isotopic substitution. | I.r. spectroscopy has been applied to the study of hydrogen-bonding of the unique ester carbonyl group of acylchymotrypsins in the oxyanion hole of the enzyme. This catalytic device provides electrophilic stabilization of negative charge in the transition states and tetrahedral intermediates along the reaction pathway.... |
1415185 | Role of endothelin in disseminated intravascular coagulation. | We examined the changes in plasma levels of endothelin-1 (ET-1), a potent vasoconstrictor peptide, in 47 cases of disseminated intravascular coagulation (DIC) to investigate the role of ET-1 in DIC and its relation to multiple organ failure (MOF). A significant elevation of plasma levels of ET-1 was observed in some ca... |
1409713 | Helical model of nucleation and propagation to account for the growth of type I collagen fibrils from symmetrical pointed tips: a special example of self-assembly of rod-like monomers. | A model was developed to account for the recent observations indicating that type I collagen fibrils assembled in vivo grow from symmetrical pointed tips. The essential features of the model are (i) a distinctive structural nucleus forms at each end of a growing fibril and growth of the fibril then proceeds by propagat... |
1409712 | Growing tips of type I collagen fibrils formed in vitro are near-paraboloidal in shape, implying a reciprocal relationship between accretion and diameter. | Collagen fibrils generated in vitro at 37 degrees C by enzymic removal of C-terminal propeptides from type I pC-collagen (an intermediate in the normal processing of type I procollagen to collagen containing the C-terminal propeptides but not the N-terminal propeptides) display shape polarity, with one tip fine tapered... |
1409708 | Roles of selection and recombination in the evolution of type I restriction-modification systems in enterobacteria. | Restriction-modification systems can protect bacteria against viral infection. Sequences of the hsdM gene, encoding one of the three subunits of type I restriction-modification systems, have been determined for four strains of enterobacteria. Comparison with the known sequences of EcoK and EcoR124 indicates that all ar... |
1409671 | Mutational analysis of the integrase protein of human immunodeficiency virus type 2. | Purified integrase protein (IN) can nick linear viral DNA at a specific site near the ends and integrate nicked viral DNA into target DNA. We have made a series of 43 site-directed point mutants of human immunodeficiency virus type 2 IN and assayed purified mutant proteins for the following activities: site-specific cl... |
1409642 | Peptoids: a modular approach to drug discovery. | Peptoids, oligomers of N-substituted glycines, are described as a motif for the generation of chemically diverse libraries of novel molecules. Ramachandran-type plots were calculated and indicate a greater diversity of conformational states available for peptoids than for peptides. The monomers incorporate t-butyl-base... |
1384035 | In vitro selection of an RNA epitope immunologically cross-reactive with a peptide. | An antiserum raised against a peptide was used to select a unique RNA species from a degenerate pool of RNAs designed to resemble an autoantibody recognition site in U1 RNA. The peptide and the selected RNA epitope could compete for antibody binding, suggesting that both RNA and peptide epitopes occupy the same or over... |
1408824 | Nonenzymatic hydrolysis of oligoribonucleotides. | Selective cleavage of phosphodiester bonds in RNA is important in the processing of large RNA molecules. This paper reports specific cleavage at UA sequences in single stranded oligoribonucleotides as short as hexamers. The hydrolysis between U and A leaves a 2',3'-cyclic phosphate on the 5'-side and a 5'-hydroxyl grou... |
1329035 | Interaction of hnRNP A1 with snRNPs and pre-mRNAs: evidence for a possible role of A1 RNA annealing activity in the first steps of spliceosome assembly. | The in vitro interaction of recombinant hnRNP A1 with purified snRNPs and with pre-mRNAs was investigated. We show that protein A1 can stably bind U2 and U4 snRNP but not U1. Oligo-RNAse H cleavage of U2 nucleotides involved in base pairing with the branch site, totally eliminates the A1-U2 interaction. RNase T1 protec... |
1328860 | Jun is phosphorylated by several protein kinases at the same sites that are modified in serum-stimulated fibroblasts. | c-jun is a member of the family of immediate-early genes whose expression is induced by factors such as serum stimulation, phorbol ester, and differentiation signals. Here we show that increased Jun synthesis after serum stimulation is accompanied by a concomitant increase in phosphorylation. Several serine-threonine k... |
1406629 | Histone H2B gene transcription during Xenopus early development requires functional cooperation between proteins bound to the CCAAT and octamer motifs. | The ubiquitously expressed transcription factor Oct-1 and several other members of the POU domain protein family bind to a site, termed the octamer motif, that functions in the promoter and enhancer regions of a variety of genes expressed under diverse conditions. An octamer motif present in a conserved histone H2B-spe... |
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