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8771201 | Human protoporphyrinogen oxidase: expression, purification, and characterization of the cloned enzyme. | Protoporphyrinogen oxidase (E.C.1.3.3.4) catalyzes the oxygen-dependent oxidation of protoporphyrinogen IX to protoporphyrin IX. The enzyme from human placenta has been cloned, sequenced, expressed in Escherichia coli, purified to homogeneity, and characterized. Northern blot analysis of eight different human tissues s... |
8770227 | Self-assembly of biopolymeric structures below the threshold of random cross-link percolation. | Self-assembly of extended structures via cross-linking of individual biomolecules often occurs in solutions at concentrations well below the estimated threshold for random cross-link percolation. This requires solute-solute correlations. Here we study bovine serum albumin. Its unfolding causes the appearance of an inst... |
8770220 | Spectroscopic and molecular modeling studies of caffeine complexes with DNA intercalators. | Recent studies have demonstrated that caffeine can act as an antimutagen and inhibit the cytoxic and/or cytostatic effects of some DNA intercalating agents. It has been suggested that this inhibitory effect may be due to complexation of the DNA intercalator with caffeine. In this study we employ optical absorption, flu... |
8770187 | Visualization of beta-sheets and side-chain clusters in two-dimensional periodic arrays of streptavidin on phospholipid monolayers by electron crystallography. | The biotin-binding protein streptavidin was crystallized as two-dimensional periodic arrays on biotinylated phospholipid monolayers. Electron diffraction patterns and images of the arrays embedded in vitreous ice were recorded to near-atomic resolution. Amplitudes and phases of structure factors were computed and combi... |
10160205 | Consensus on surfactant and inhaled nitric oxide for ARDS. | Adult respiratory distress syndrome (ARDS) remains a major problem in intensive care medicine. While the triggers are not well understood, the process often involves generalized neutrophil activation and sequestration in the lung which initiate inflammatory cascades. These effects can be localized to the pulmonary tiss... |
8742744 | Visualization of three-dimensional density maps reconstructed from cryoelectron micrographs of viral capsids. | Full evaluation of three-dimensional density maps calculated from cryoelectron micrographs of complex supramolecular structures requires that the maps be sifted by a variety of complementary visualization techniques. We present here a primer for a number of such techniques in current widespread use, including surface r... |
8742730 | AVS software for visualization in molecular microscopy. | AVS (Application Visualization System) is commercially available software for analyzing and viewing data. AVS is primarily used in the physical sciences and engineering, and here we describe the application of AVS for examining three-dimensional density maps generated by electron microscopy and image processing. For th... |
8742728 | Real-time isocontouring and texture mapping meet new challenges in interactive molecular graphics applications. | A technique to extract solid isosurfaces from three-dimensional electron density data at high speed is presented. The ability to change the contouring threshold in real time renders the method a powerful tool for interactive analysis of proteins and their supramolecular assemblies, in order to compare and combine struc... |
8748284 | Biochemical investigations of biogroups and subspecies of Morganella morganii. | We determined the subspecies and biogroup designations for 73 strains of Morganella morganii principally recovered from routine clinical specimens. On the basis of trehalose fermentation, 90% of all strains were identified as M. morganii subsp. morganii (trehalose negative), while the remaining 10% were designated M. m... |
8741985 | Boronated epidermal growth factor as a potential targeting agent for boron neutron capture therapy of brain tumors. | In order for boron neutron capture therapy (BNCT) to be successful, a large number (approximately 10(9)) of 10B atoms must be delivered to each cancer cell in order to sustain a lethal 10B(n, alpha)7Li reaction. The majority of high grade gliomas express an amplified epidermal growth factor receptor (EGFR) gene, and in... |
8765305 | Molecular recognition of lysozyme by monoclonal antibodies. | HEL was one of the first proteins to be mapped antigenically using mAb, and panels of mAb have been used as a measure of antigenicity in order to study regulation of the immune response and the apparent 'antigenic structure' of HEL. These studies have confirmed the multideterminant hypothesis derived from pAb. However,... |
8743309 | Phage display of proteases and macromolecular inhibitors. | We describe methods for displaying the protease trypsin and the macromolecular protease inhibitor ecotin on the surface of filamentous phage. Our strategy for selecting variant ecotins against target proteases is also described. We believe that the two proteins that have been displayed serve as ideal models for studyin... |
8701089 | Extracellular matrix signaling from the cellular membrane skeleton to the nuclear skeleton: a model of gene regulation. | It is well established that cells must interact with their microenvironment and that such interaction is crucial for coordinated function and homeostasis. However, how cells receive and integrate external signals leading to gene regulation is far from understood. It is now appreciated that two classes of cooperative si... |
8762651 | [The role of the polymorphonuclear neutrophil in the failure of multiple organs and systems]. | The role of the polymorphonuclear neutrophil (PMN) on MOF is analyzed either as PMN activation for superoxide and enzyme release, or as PMN function depression after trauma and surgery. The authors stress: 1) the signal transduction pathway from the PMN membrane receptors to the effector response; 2) the PMN-NADPH syst... |
8688165 | Chemiluminescent immunoenzyme biosensor with a thin-layer flow-through cell. Application for study of a real-time bimolecular antigen-antibody interaction. | A simple flow enzyme system for real-time continuous monitoring of interaction of biological molecules has been developed. It relies upon a thin-layer flow-through cell placed directly into the measuring compartment of the luminometer. One ligand (antibody) is immobilized on the inner surfaces of the flow cuvette, and ... |
8766694 | Energetics of cyclodextrin-induced dissociation of insulin. | The energetics of dissociation of bovine insulin in aqueous solution have been investigated by sensitive dilution microcalorimetry. Cyclodextrins increase dissociation of insulin oligomers in a manner consistent with their interaction with protein side chains. For example, assuming monomer-dimer equilibrium, in the abs... |
8766689 | Molecular dynamics study of an alpha-cyclodextrin-phosphatidylinositol inclusion complex. | Cyclodextrins are cyclic oligosaccharides known for their ability to include substrate molecules in their hydrophobic cavity. Moreover, cyclodextrins show a hemolytic activity when mM concentrations are added to blood. This hemolysis is commonly interpreted as a massive dissociation of phospholipids from the cell membr... |
8723318 | Comparative interaction kinetics of two recombinant Fabs and of the corresponding antibodies directed to the coat protein of tobacco mosaic virus. | Two recombinant Fab fragments, 57P and 174P, recognizing peptide 134-146 of the coat protein of tobacco mosaic virus have been cloned, sequenced and expressed in Escherichia coli. They differ by 15 amino acid changes in the sequence of their variable region. The interaction kinetics of the Fabs with the wild-type and f... |
8723317 | Binding of fibrinogen to platelet integrin alpha IIb beta 3 in solution as monitored by tracer sedimentation equilibrium. | Fibrinogen showed essentially no binding (KD > 1 mM) to platelet alpha IIb beta 3 integrin in solution in the presence of Triton or octylglucoside above critical micellar concentrations. Under these conditions the integrin was an alpha beta monomer. After removal of the detergent from the Triton containing buffer (25 m... |
8723316 | Roles of lysine-69 in dimerization and activity of Trimeresurus flavoviridis venom aspartate-49-phospholipase A2. | Trimeresurus flavoviridis (Habu snake) venom aspartate-49-phospholipase A2 (Asp-49-PLA2) was reacted at pH 9.0 with a 2-fold molar excess of 2,4,6-trinitrobenzenesulfonate in the absence of Ca2+ and two trinitrophenylated derivatives were isolated by HPLC. One was a derivative modified at Lys-11 and its activity was mo... |
8723315 | Lac repressor-operator interaction: N-terminal peptide backbone 1H and 15N chemical shifts upon complex formation with DNA. | When the lac repressor tetramer is bound to its DNA operator, methylation protection shows the nearly symmetric operator half-sites are contracted asymmetrically. This asymmetric binding results from the DNA sequence/structure. The reported structure of lac repressor N-terminal fragment and an 11 base-pair operator lef... |
8723314 | The effect of water activity on the association constant and the enthalpy of reaction between lysozyme and the specific antibodies D1.3 and D44.1. | The reactions of lysozyme with the specific monoclonal antibody D1.3, its Fv fragment and a mutant of the Fv, were studied under conditions of reduced water activity through the addition of the cosolutes glycerol, ethanol, dioxane and methanol. Titration calorimetry, BIAcoreTM and ultracentrifugal analyses were used to... |
8723313 | Automated docking of flexible ligands: applications of AutoDock. | AutoDock is a suite of C programs used to predict the bound conformations of a small, flexible ligand to a macromolecular target of known structure. The technique combines simulated annealing for conformation searching with a rapid grid-based method of energy evaluation. This paper reviews recent applications of the te... |
8722490 | In-vitro evaluation of biphenylyl acetic acid-beta-cyclodextrin conjugates as colon-targeting prodrugs: drug release behaviour in rat biological media. | Biphenylyl acetic acid was selectively conjugated to one of the primary hydroxyl groups of beta-cyclodextrin through an ester- or amide-linkage, and the physicochemical properties (aqueous solubility and hydrolysis) were investigated. Aqueous solubility of the conjugates was lower than those of either drug or parent be... |
8653196 | Postcolumn excitation of aflatoxins using cyclodextrins in liquid chromatography for food analysis. | Measurement of fluorescence increase was used for the comparative quantification of the effect that several cyclodextrins (alpha-, beta-, heptakis-2,6-beta-omicron-dimethyl- and gamma-) produce on the fluorescent response of aflatoxins B1 and G1. This constitutes a new chromatographic method with stability of the mobil... |
9019306 | Molecular recognition of phenobarbital in plasticizers equilibrium investigations on the solubility of the barbiturate artificial receptor and its binding to phenobarbital in plasticizers. | Environmental concern is renewing interest in selective, waste-free extractions. A recent report demonstrated an improved extraction of phenobarbital by means of a specifically designed molecular receptor. In that work, the solvent was CHCl3. The current work is the first step in extending extractions based on molecula... |
8848456 | Estradiol benzoate potentiates neuroactive steroids' effects on pain sensitivity. | Progesterone (P), its metabolites, and other neuroactive steroids alter pain thresholds consistent with their efficacies at modulating gamma-aminobutyric acid (GABAA) receptor complexes. We investigated whether estradiol benzoate (EB) potentiates low dosages of neuroactive steroids' effects on pain. Subcutaneous EB (10... |
8845279 | Determination of the enantiomeric composition of mexiletine and its four hydroxylated metabolites in urine by enantioselective capillary gas chromatography. | The enantiomers of mexiletine and four of its hydroxylated metabolites were directly separated by capillary gas chromatography using a heptakis(6-O-tert-butyl-dimethylsilyl-2,3-di-O-methyl)-beta- cyclodextrin column. The method was applied to the analysis of urine samples from cancer patients who were treated with race... |
8999434 | Improvement of some pharmaceutical properties of drugs by cyclodextrin complexation. 5. Theophylline. | The interaction of theophylline (TPH) with beta-cyclodextrin (beta-CD) was investigated by spectrophotometry, vapour pressure osmometry and DSC. The results revealed a molecular interaction between TPH and beta-CD. The continuous variation method was used to elucidate the stoichiometry of such an interaction by spectro... |
8999433 | Design and in vivo testing of 17 beta-estradiol-HP beta CD sublingual tablets. | 17 beta-Estradiol is almost insoluble in water. The effect of various cyclodextrins and two different polymers, polyvinylpyrrolidone (PVP) and carboxymethylcellulose (CMC), on the aqueous solubility of 17 beta-estradiol was investigated. 17 beta-Estradiol was dissolved in aqueous 50% w/v 2-hydroxypropyl-beta- cyclodext... |
8653274 | G-banding and chromosome condensation in the ant, Tapinoma nigerrimum. | Well-defined G-bands were obtained on metaphase chromosomes from Tapinoma nigerrimum using trypsin and warm 2 x SSC in sequence. The G-banded pattern allowed the identification of all chromosomes. Evidence for asynchronous condensation of the chromosomes of this species is provided. Different banding patterns were obta... |
8653273 | Chiasma localization, heterochromatin and synaptonemal complexes in the grasshopper Pyrgomorpha conica. | Surface-spread synaptonemal complexes and chiasma distributions in spermatocytes with different C-banding patterns and chiasma distributions in oocytes were analyzed in the grasshopper Pyrgomorpha conica. Male meiosis was characterized by a proximal/distal chiasma localization and complete pairing of homologous chromos... |
8653272 | Analysis using dual-colour fluorescence in situ hybridization of meiotic chromosome segregation in male mice heterozygous for a reciprocal translocation. | Meiotic chromosome behaviour was investigated in male mice heterozygous for the translocation T(7;16)67H. At metaphase I, chain-of-four quadrivalents were present in approximately 80% of the spermatocytes; the bulk of remaining cells contained a ring quadrivalent, with only a few having either a trivalent plus univalen... |
8653271 | Patterns of DNase I sensitivity in the chromosomes of the grasshopper Chorthippus parallelus (Orthoptera). | We have analysed the patterns of DNase I/nick translation in the chromosomes of the grasshopper Chorthippus parallelus erythropus. Sites of preferential DNase I-nicking were concentrated at the distal chromosome regions, thus showing the non-uniform DNase I sensitivity of different chromosome domains. Among centromeric... |
8653269 | The chromosomal distribution and organization of sheep satellite I and II centromeric DNA using characterized sheep-hamster somatic cell hybrids. | A panel of sheep-hamster somatic cell hybrids containing single sheep chromosomes was used to study the chromosomal distribution and organization of two families of sheep centromeric satellite DNA. This study shows that the centromeres of the sheep metacentric chromosomes 1, 2 and 3 differ in their organization and rel... |
8653268 | Achiasmate segregation of X and B univalents in males of the grasshopper Eyprepocnemis plorans is independent of previous association. | B chromosomes proved to be more frequent in males than females of the grasshopper Eyprepocnemis plorans collected from the population in Jete (Granada, Spain) in 1992. The meiotic behaviour of the X and B univalents was analysed in a high number of 1B males collected from this population in 1991 and 1992, and in males ... |
8653267 | Comparative fluorescence in situ hybridization mapping of primate chromosomes with Alu polymerase chain reaction generated probes from human/rodent somatic cell hybrids. | We have used Alu polymerase chain reaction generated probes from rearranged human/rodent somatic cell hybrids for fluorescence in situ hybridization and comparative mapping of some intrachromosomal changes in the karyotypes of great apes (Pan troglodytes, P. paniscus, Gorilla gorilla, Pongo pygmaeus), a gibbon (Hylobat... |
8653266 | Mapping of 22 Notl linking clones on human chromosome 3 by polymerase chain reaction and somatic cell hybrid panels. | Twenty-two human chromosome 3 derived and partially sequenced Notl linking clones were mapped using two somatic cell hybrid panels. Somatic cell hybrid mapping was performed by Southern hybridization and/or by polymerase chain reaction (PCR), using 300-500 bp CpG-rich sequences surrounding Notl sites. Thus, 22 new Notl... |
8653265 | Chromosome complement, C-banding, Ag-NOR and replication banding in the zebrafish Danio rerio. | The chromosome complement of Danio rerio was investigated by Giemsa staining and C-banding, Ag-NORs and replication banding. The diploid number of this species is 2n = 50 and the arm number (NF) = 100. Constitutive heterochromatin was located at the centromeric position of all chromosome pairs. Nucleolus organizer regi... |
8653264 | Preparation of tomato meiotic pachytene and mitotic metaphase chromosomes suitable for fluorescence in situ hybridization (FISH). | Fluorescence in situ hybridization (FISH) is an increasingly powerful tool with a variety of applications in both basic and applied research. With excellent genetic, cytogenetic and molecular maps available, the tomato genome provides a good model to benefit from the full potential of FISH. Tomato chromosomes at mitoti... |
8653263 | Molecular analysis of the structure of the maize B-chromosome. | The overall composition of the maize B is similar to that of the standard chromosome complement (A-chromosomes). This has been demonstrated by the use of several methods including: (a) genomic in situ hybridization (GISH), (b) analysis of highly repetitive sequences by the comparison of restriction digests of 0B and +B... |
8653270 | The distribution of topoisomerase II on mammalian chromosomes. | The distribution of topoisomerase II (Topo II) has been studied using immunofluorescence on cytocentrifuged preparations of mammalian chromosomes. Immunolabelling of Topo II is affected by choice of fixative, by barriers to accessibility and by the lability of the enzyme. Chromosomes still embedded in cytoplasm remain ... |
8779436 | Mass spectrometric analyses of beta-ketolactone oligomers, macrocyclic or catenane structures? | Mass spectrometry is used to develop an analytical method for a new class of organic oligomeric material, beta-ketolactones. Three different series with varying oligomeric sizes are examined. The oligomers may form at least two different structures, a macrocyclic and a catenane ring. Fast atom bombardment coupled with ... |
9004912 | An Rh-105 complex of tetrathiacyclohexadecane diol with potential for formulating bifunctional chelates. | 1,5,9,13-Tetrathiacyclohexane-3,11-diol (16S4-diol), a sulfur crown ether analog, was studied as a potential chelating agent to complex no-carrier-added (NCA) grade 105Rh(III) in high yield at low ligand concentrations. trans-[RhCl2(16S4-diol)]chi (chi = Cl, PF6) was prepared using nonradioactive RhCl3.3H2O and charact... |
8668684 | Pulmonary delivery of salmon calcitonin dry powders containing absorption enhancers in rats. | <h4>Purpose</h4>To evaluate the effects of absorption enhancers in dry powders and in liquids, pulmonary absorption of salmon calcitonin (sCT) in various formulations was measured.<h4>Methods</h4>The dry powder of sCT was prepared by a freeze-drying method with a jet mill. After intratracheal administration of sCT dry ... |
8634755 | Enantioselective determination of zopiclone and its metabolites in urine by capillary electrophoresis. | A method has been developed for the stereoselective determination of zopiclone and its main metabolites in urine. After the addition of the internal standard zolpidem the urine samples were extracted at pH 8 with chloroform-isopropanol (9:1). Analyses were carried out using capillary electrophoresis (CE) with beta-cycl... |
8637411 | Effects of topical anandamides on intraocular pressure in normotensive rabbits. | A series of anandamide-type compounds were synthesized and studied for their effect on the intraocular pressure (IOP) of normotensive pigmented rabbits. Each test compound was dissolved in an aqueous 2-hydroxypropyl-beta-cyclodextrin solution and administered (31.25 - 62.5 micrograms) unilaterally to the eye. The most ... |
8616908 | Comparison of several antiangiogenic regimens alone and with cytotoxic therapies in the Lewis lung carcinoma. | The efficacy of several potential antiangiogenic agents, TNP-470, minocycline, suramin, genistein, interferon delta 4, 14(sulfated)-beta-cyclodextrin and tetrahydrocortisol, alone and in combination with cytotoxic therapies was examined against primary and metastatic Lewis lung carcinoma. The antiangiogenic agents when... |
8631346 | Synthesis of stereoisomers and isoforms of a tryptic heptapeptide fragment of human growth hormone and analysis by reverse-phase HPLC and capillary electrophoresis. | The amino acid sequence Asn-Gly has at pH 7 a tendency to induce deamidation of asparagine to aspartic acid via the formation of a cyclic imide. This imide opens up to yield Asp-Gly or the isoaspartic acid (isoAsp) form, isoAsp-Gly. Both isomers may be found in their L-form or D-form. Like Asn-Gly, the sequence Asp-Gly... |
8611942 | Quantitative structure-activity relationships studies with micellar electrokinetic chromatography. Influence of surfactant type and mixed micelles on estimation of hydrophobicity and bioavailability. | Applications of micellar electrokinetic chromatography (MEKC) in quantitative structure-activity relationships (QSAR) were studied. First, quantitative structure-retention relationships (QSRR), which describe the correlation between logarithm of capacity factor (log k') in MEKC and logarithm of distribution coefficient... |
8611612 | Cyclodextrins: a new tool for the controlled lipid depletion of thylakoid membranes. | Cyclodextrins (CDs) have been used in controlled lipid depletion of thylakoid membranes avoiding the use of either detergents or lipolytic enzymes. Spinach thylakoid membranes were first treated with different CDs under various conditions. After removal of the CDs by washing, the amounts of mono-- and digalactosyldiacy... |
8624133 | Structure, microtubule interactions, and phosphorylation of tau protein. | This paper summarizes recent structural and functional studies on tau protein, its interactions with microtubules, its self-assembly into paired helical filaments (PHF)-like fibers, and its modification by phosphorylation. The structure of tau in solution resembles that of a random coil. Both tau and Alzheimer PHFs hav... |
8602110 | Hydroxypropyl-beta-cyclodextrin increases aqueous solubility and stability of anandamide. | Anandamide (arachidonylethanolamide; AEA) is an endogenous ligand for the cannabinoid receptor and its pharmacological effects are under intensive study. However, AEA has a low aqueous solubility and stability which may restrict its use and may eventually endanger the reliability of the obtained results. In the present... |
8617211 | Genetic analysis of glucose regulation in saccharomyces cerevisiae: control of transcription versus mRNA turnover. | A major determinant of the steady-state level of the mRNA encoding the iron protein (Ip) subunit of succinate dehydrogenase of yeast is its rate of turnover. This mRNA is significantly more stable in glycerol than in glucose media. Many other genes, for example, SUC2, that are repressed in the presence of glucose are b... |
8617204 | A novel vascular endothelial growth factor, VEGF-C, is a ligand for the Flt4 (VEGFR-3) and KDR (VEGFR-2) receptor tyrosine kinases. | Angiogenesis, the sprouting of new blood vessels from pre-existing ones, and the permeability of blood vessels are regulated by vascular endothelial growth factor (VEGF) via its two known receptors Flt1 (VEGFR-1) and KDR/Flk-1 (VEGFR-2). The Flt4 receptor tyrosine kinase is related to the VEGF receptors, but does not b... |
8594590 | MHCPEP--a database of MHC-binding peptides: update 1995. | MHCPEP is a curated database comprising over 6000 peptide sequences known to bind MHC molecules. Entries are compiled from published reports as well as from direct submissions of experimental data. Each entry contains peptide sequence, MHC specificity and when available, experimental method, observed activity, binding ... |
8601188 | High-performance liquid chromatographic separation of carbohydrates on graphitized carbon columns. | Graphitized carbon columns (GCC) for high-performance liquid chromatography are relatively new and have a unique ability to resolve isomeric and closely related compounds. The retention mechanism of carbohydrates on GCC is mainly based on adsorption and the flat surface of GCC packings brings about unique selectivity, ... |
8579605 | Sequences in the myosin II tail required for self-association. | The assembly of myosin II molecules into a filament requires the electrostatic interaction of a domain localized toward the carboxyl-terminus of the myosin II tail. However, the precise sequences involved in this interaction are not known. Here we show that the smallest Dictyostelium myosin II fragment that is necessar... |
8592435 | Serum phospholipase A2 in patients with multiple organ failure. | Multiple organ failure (MOF) is the most common cause of death in the surgical intensive care unit. We studied the relation of MOF to changes in the concentration of group II phospholipase A2 (PLA2) in serum. Altogether, 215 surgical intensive care patients with multiple injuries, diffuse peritonitis, or sepsis and con... |
8560261 | Reversible encapsulation of disc-shaped guests by a synthetic, self-assembled host. | Here, the synthesis of a bowl-shaped molecule is described and evidence of its reversible dimerization by means of hydrogen bonds is presented. The dimer features a flattened spherical cavity of peculiar symmetry and acts as a host for the encapsulation of guest molecules of complementary shape. Encapsulation of aromat... |
8567720 | A nontetrameric species is the major soluble form of keratin in Xenopus oocytes and rabbit reticulocyte lysates. | Inside the interphase cell, approximately 5% of the total intermediate filament protein exists in a soluble form. Past studies using velocity gradient sedimentation (VGS) indicate that soluble intermediate filament protein exists as an approximately 7 S tetrameric species. While studying intermediate filament assembly ... |
8565593 | Cytotoxicity and membrane damage in vitro by inclusion complexes between gamma-cyclodextrin and siloxanes. | Inclusion complexes of gamma-cyclodextrin and octamethylcyclotetrasiloxane (D4), decamethyltetrasiloxane (M10TS), and 1,3,5,7-tetramethyltetravinylcyclotetra - siloxane (TMTV-D4) were prepared to compare the cytotoxic effects of siloxanes in vitro. In these preparations, the hydrophobic siloxanes are surrounded by a hy... |
8554982 | Hexadecafluorinated zinc phthalocyanine: photodynamic properties against the EMT-6 tumour in mice and pharmacokinetics using 65Zn as a radiotracer. | Hexadecafluorinated zinc phthalocyanine (ZnPcF16), an analogue of zinc phthalocyanine (ZnPc) in which all hydrogen atoms have been substituted by fluorine, was prepared as a single isomeric product via the condensation of tetrafluorophthalonitrile with zinc acetate. Fluorination renders the ZnPc soluble in most common ... |
8547270 | Deletions in the interdomain hinge region of flavocytochrome b2: effects on intraprotein electron transfer. | The two distinct domains of flavocytochrome b2 (L-lactate:cytochrome c oxidoreductase, EC 1.1.2.3) are connected by a typical hinge peptide. To probe the importance of the structural integrity of the hinge region for efficient intraprotein electron transfer, three mutant enzymes have been constructed: H delta 3 [Sharp,... |
8558508 | Tetrahydrobenzothiophenone derivatives as a novel class of adenosine receptor antagonists. | A novel class of non-nitrogen-containing heterocycles, the tetrahydrobenzothiophenones, was found to bind to adenosine receptors as antagonists in the micromolar range. Affinity was determined in radioligand-binding assays at rat brain A1 and A2a receptors. A structure-activity analysis indicated that a 3-thioether gro... |
8593638 | Migration of secondary tert-butyldimethylsilyl groups in cyclomalto-heptaose and -octaose derivatives. | When 2,6-di-O-tert-butyldimethylsilylated cyclomalto-oligosaccharides (cyclodextrins) are treated with allyl or methyl iodide and NaH in dry tetrahydrofuran, O-2-->O-3 migration of the secondary 2-O-tert-butyldimethylsilyl groups occurs, leading to 2-O-alk(en)yl-3,6-di-O-tert-butyldimethylsilyl-cyclodextrin derivatives... |
8538794 | A bipolar kinesin. | Chromosome segregation during mitosis depends on the action of the mitotic spindle, a self-organizing, bipolar protein machine which uses microtubules (MTs) and their associated motors. Members of the BimC subfamily of kinesin-related MT-motor proteins are believed to be essential for the formation and functioning of a... |
8552597 | Evidence that two present-day components needed for the genetic code appeared after nucleated cells separated from eubacteria. | The trinucleotide/amino acid relationships of the present-day genetic code are established by the amino-acylation reactions of tRNA synthetases, whereby each of 20 specific amino acids is attached to its cognate tRNAs, which bear anticodon trinucleotides. Because of its universality, the appearance of the modern geneti... |
8552675 | A mean field model of ligand-protein interactions: implications for the structural assessment of human immunodeficiency virus type 1 protease complexes and receptor-specific binding. | We propose a general mean field model of ligand-protein interactions to determine the thermodynamic equilibrium of a system at finite temperature. The method is employed in structural assessments of two human immuno-deficiency virus type 1 protease complexes where the gross effects of protein flexibility are incorporat... |
8552589 | Principles of protein-protein interactions. | This review examines protein complexes in the Brookhaven Protein Databank to gain a better understanding of the principles governing the interactions involved in protein-protein recognition. The factors that influence the formation of protein-protein complexes are explored in four different types of protein-protein com... |
8552582 | Binding in the growth hormone receptor complex. | Binding reactions between human growth hormone (hGH) and its receptor provide a detailed account of how a polypeptide hormone activates its receptor and more generally how proteins interact. Through high-resolution structural and functional studies it is seen that hGH uses two different sites (site 1 and site 2) to bin... |
8551337 | Microtubule assembly and turnover in growing axons. | We have shown previously that axonal microtubules (MTs) are composite, consisting of two distinct domains that differ in their content of tyrosinated alpha-tubulin (tyr-tub). One domain is poor in tyr-tub and is situated at the minus end of the MT. The other domain is rich in tyr-tub and extends from the plus end of th... |
8557636 | Further characterization of proteins associated with elastic fiber microfibrils including the molecular cloning of MAGP-2 (MP25) | Together with the 31-kDa microfibril-associated glycoprotein (MAGP), four polypeptides designated MP340 (340 kDa), MP78 (78 kDa), MP70 (70 kDa), and MP25 (25 kDa) have previously been identified in tissue extracts designed specifically to solubilize the microfibrillar component of elastic fibers. In the present study, ... |
8541446 | Flexibility in peptide molecules and restraints imposed by hydrogen bonds, the Aib residue, and core inserts. | The first segments of this article review some of the early crystal structure determinations of beta-bends, gamma-bends, large conformational changes in cyclic peptides upon complexation with metal ions, and both the stability and drastic change in conformation as a function of the solvent used for growing crystals. Mo... |
8546704 | Biosynthesis of vitamin B12: the preparative multi-enzyme synthesis of precorrin-3A and 20-methylsirohydrochlorin (a 2,7,20-trimethylisobacteriochlorin). | The Bacillus subtilis genes hemB, hemC and hemD, encoding respectively the enzymes porphobilinogen synthase, hydroxymethylbilane synthase and uroporphyrinogen III synthase, have been expressed in Escherichia coli using a single plasmid construct. An enzyme preparation from this source converts 5-aminolaevulinic acid (A... |
8546675 | Rapid identification of compounds with enhanced antimicrobial activity by using conformationally defined combinatorial libraries. | We have combined the strength of our synthetic combinatorial library approach for the rapid identification of highly active compounds with prior knowledge of the relationship between the antimicrobial activities of individual peptides with specific induced conformations in order to identify new peptides with enhanced a... |
8550412 | Naturally occurring peptidoglycan variants of Streptococcus pneumoniae. | Analysis by high-performance liquid chromatography of the stem peptide composition of cell walls purified from a large number of pneumococcal strains indicates that these bacteria produce a highly conserved species-specific peptidoglycan independent of serotype, isolation date, and geographic origin. Characteristic fea... |
8523545 | The human papillomavirus type 16 E7 protein complements adenovirus type 5 E1A amino-terminus-dependent transactivation of adenovirus type 5 early genes and increases ATF and Oct-1 DNA binding activity. | We have previously shown that conserved region 1 (CR1) of the adenovirus type 5 (Ad5) E1A protein synergizes with CR3 in the transactivation of Ad5 early genes (H.K. Wong and E. B. Ziff, J. Virol. 68:4910-4920, 1994). CR1 lies within the E1A amino terminus and binds host regulatory proteins such as the RB protein, p107... |
8523525 | The promoter activity of long terminal repeats of the HERV-H family of human retrovirus-like elements is critically dependent on Sp1 family proteins interacting with a GC/GT box located immediately 3' to the TATA box. | The HERV-H family of endogenous retrovirus-like elements is widely distributed in the human genome, with about 1,000 full-length elements and a similar number of solitary long terminal repeats (LTRs). HERV-H LTRs have been shown to direct the transcription of both HERV-H-encoded and adjacent cellular genes. Transcripts... |
8523515 | E2 represses the late gene promoter of human papillomavirus type 8 at high concentrations by interfering with cellular factors. | The late gene promoter P7535 of the epidermodysplasia verruciformis-associated human papillomavirus type 8 (HPV8) is regulated by the viral E2 protein. Transfection experiments performed with the human skin keratinocyte cell line RTS3b and P7535 reporter plasmids revealed transactivation at low amounts and a repression... |
8523569 | Complete inhibition of virion assembly in vivo with mutant procapsid RNA essential for phage phi 29 DNA packaging. | A highly efficient method for the inhibition of bacteriophage phi 29 assembly was developed with the use of mutant forms of the viral procapsid (or packaging) RNA (pRNA) indispensable for phi 29 DNA packaging. Phage phi 29 assembly was severely reduced in vitro in the presence of mutant pRNA and completely blocked in v... |
8523550 | Directed integration of viral DNA mediated by fusion proteins consisting of human immunodeficiency virus type 1 integrase and Escherichia coli LexA protein. | We tested whether the selection of target sites can be manipulated by fusing retroviral integrase with a sequence-specific DNA-binding protein. A hybrid protein that has the Escherichia coli LexA protein fused to the C terminus of the human immunodeficiency virus type 1 integrase was constructed. The fusion protein, IN... |
25147430 | NEW BASE-ALTERED ADENOSINE ANALOGUES: SYNTHESIS AND AFFINITY AT ADENOSINE A<sub>1</sub> and A<sub>2A</sub> RECEPTORS. | N<sup>6</sup>-Substituted adenosine analogues containing cyclic hydrazines or chiral hydroxy (ar)alkyl groups, designed to interact with the S2 and S3 receptor subregions, have been synthesized and their binding to the adenosine A<sub>1</sub> and A<sub>2A</sub> receptors have been investigated. Examples of both types o... |
23345662 | Influence of Medium and Long Range Interactions in (α/β)(8) Barrel Proteins. | The residue-residue contacts and the role of medium and long rangeinteractions in 36 (α/β)(8) barrel proteins have beenanalysed. The influence of long range contacts in the formation ofphysico-chemically similar clusters, and the preference of amino acidresidues towards long range contacts have also been studied. There... |
18982260 | Solubility and stability of melatonin in propylene glycol and 2-hydroxypropyl-beta-cyclodextrin vehicles. | The physicochemical properties of melatonin (MT) in propylene glycol (PG) and 2-hydroxypropyl-beta-cyclodextrin (2-HPbetaCD) vehicles were characterized. MT was endothermally decomposed as determined by differential scanning calorimetry (DSC). Melting point and heat of fusion obtained were 116.9+/-0.24 degrees C and 72... |
18967007 | Enhancement of fluorescence of terbium/trimesic acid/cyclodextrin system by zirconate and its application to the determination of terbium. | A new approach of fluorescence enhancement for the determination of terbium based on the formation of a new fluorescence system of Tb-TMA-beta-CD (benzene-1,3,5-tricarboxylic acid (TMA), beta-cyclodextrin (beta-CD)) in an aqueous medium of pH 5.0 provided by a HAc-NaAc buffer in the presence of an oxy-acid of transitio... |
18966968 | Fluorimetric properties of a 2-hydroxypropyl-beta-cyclodextrin: 9-methyl-benzo[a]phenothiazine inclusion complex in aqueous media. Analytical usefulness. | The formation of an inclusion complex between 9-methyl-12H-benzo[a]phenothiazine (MeBPHT) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD) was investigated in aqueous medium. A 12-fold fluorescence emission intensity enhancement was found for the complexed relative to the free analyte. MeBPHT forms a 1:1 stoichiometr... |
16844613 | Energy expenditure in patients with multiple organ failure. | We measured the level of resting energy expenditure (BEE) and its evolution in patients with multiple organ failure (MOF). We studied 30 patients requiring mechanical ventilation and sedation. REE was measured by means of a closed circuit method on days 1-5, 7, 10 and 14 after initiating the protocol. REE values betwee... |
9391168 | Phloem sap proteins from Cucurbita maxima and Ricinus communis have the capacity to traffic cell to cell through plasmodesmata. | In angiosperms, the functional enucleate sieve tube system of the phloem appears to be maintained by the surrounding companion cells. In this study, we tested the hypothesis that polypeptides present within the phloem sap traffic cell to cell from the companion cells, where they are synthesized, into the sieve tube via... |
9391069 | Relationship between the oxidation potential and electron spin density of the primary electron donor in reaction centers from Rhodobacter sphaeroides. | The primary electron donor in bacterial reaction centers is a dimer of bacteriochlorophyll a molecules, labeled L or M based on their proximity to the symmetry-related protein subunits. The electronic structure of the bacteriochlorophyll dimer was probed by introducing small systematic variations in the bacteriochlorop... |
11670248 | Stepwise Approach to Bimetalic Porphyrin Hosts: Spatially Enforced Coordination of a Nickel(II) Porphyrin. | The synthesis of the Zn(3) 1,1,2-trimer Zn(3)()3 and the NiZn(2) 1,1,2-trimer NiZn(2)()3 by a stepwise convergent route is described. A large affinity for Py(3)()T by both cyclic 1,1,2-trimers, Zn(3)()3 or NiZn(2)()3, with respect to the linear trimers, provides a thermodynamic driving force for the templated cyclizati... |
11670247 | Synthesis and Structural Characterization of Nonplanar Tetraphenylporphyrins and Their Metal Complexes with Graded Degrees of beta-Ethyl Substitution. | Different porphyrin conformations are believed to play a role in controlling the cofactor properties in natural tetrapyrrole-protein complexes. In order to study the correlation between macrocycle nonplanarity and physicochemical properties in detail, a series of six porphyrins with graded degrees of macrocycle distort... |
11670243 | Tsalen- and Tsalpn-Based Nickel Complexes with Two Aldehyde Functionalities as Potential Synthons for Thiophenolate-Containing Di- and Polynucleating Acyclic and Macrocyclic Ligands. | Tsalen- and tsalpn-based nickel complexes with aldehyde functionalities have been prepared (tsalen = N,N'-ethylenebis(thiosalicylideneaminato)(2-) and tsalpn = N,N'-propane-1,3-diyl(thiosalicylideneaminato)(2-)). One of the complexes has been structurally characterized: Ni(pftp) (pftp = N,N-ethylene(6-formyl-4-methyl-2... |
11670211 | New Ionophoric Calix[4]diquinones: Coordination Chemistry, Electrochemistry, and X-ray Crystal Structures. | A new library of ionophoric p-tert-butylcalix[4]diquinones containing ester (1), primary, secondary, and tertiary amide (2-4), and crown ether (5) substituents has been synthesized by treatment of the respective 1,3-bis-substituted p-tert-butylcalix[4]arene with Tl(OCOCF(3))(3) in trifluoroacetic acid. The structures o... |
11670192 | The Coordination Chemistry of Fluorocarbons: Difluoro-m-cyclophane-Based Fluorocryptands and Their Group I and II Metal Ion Complexes. | The reactions of 1,3-bis(bromomethyl)-2-fluorobenzene with the bis(trifluoroacetamides) of 1,3-bis(aminomethyl)-2-fluorobenzene and 1,3-bis(aminomethyl)benzene yield the respective 1+1-condensed [3.3]-m-cyclophanes, respectively termed F(2)-phane (yield 39%) and HF-phane (yield 48%) without trifluoroacetamide groups. T... |
9507370 | In vitro expression analysis of collagen biosynthesis and assembly. | While the generalised pathway of collagen biosynthesis is well understood, the specific molecular interactions that drive chain recognition and assembly and the formation of tissue-specific extracellular supramolecular structures have not been elucidated. This review focuses on the use of in vitro collagen expression s... |
9504901 | Determination of hepatic acyl-coenzyme A-cholesterol acyltransferase activity in LPN hamsters: a model for cholesterol gallstone formation. | Acyl-coenzyme A-cholesterol acyltransferase (ACAT) catalyses the esterification of cholesterol with long-chain fatty acyl-coenzyme A derivatives and has been implicated in the development of cholesterol gallstones. In this study we have examined several key components of the hepatic ACAT assay in order to develop a rel... |
9476114 | Controlling the complement system in inflammation. | Inappropriate or excessive activation of the complement system can lead to harmful, potentially life-threatening consequences due to severe inflammatory tissue destruction. These consequences are clinically manifested in various disorders, including septic shock, multiple organ failure and hyperacute graft rejection. G... |
9470411 | The formation of hyphae of Candida albicans induced by cyclodextrins. | Hyphal growth of Candida albicans was observed when yeast was cultured at 27 degrees C in liquid media containing 1% Tripcasine and 1.8% cyclodextrins (alpha, beta, and gamma respectively). Tripcasine as the sole nitrogen source did not induce the formation of hyphae of C. albicans, but cyclodextrins, especially CD-bet... |
9463912 | Achiral selectivity in cyclodextrin-modified capillary electrophoresis. | Torus-shaped, circular, and hydrophilic cyclodextrins (CD) have been frequently used in capillary electrophoresis (CE) as buffer modifiers to effect chiral separation of enantiomers of drugs and specialty chemicals. Although less common, both neutral and charged cyclodextrins have also been exploited in CE to optimize ... |
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