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10488145 | Metal-dependent self-assembly of protein tubes from Escherichia coli glutamine synthetase. Cu(2+) EPR studies of the ligation and stoichiometry of intermolecular metal binding sites. | Escherichia coli glutamine synthetase (GS) is a dodecameric assembly of identical subunits arranged as two back-to-back hexagonal rings. In the presence of divalent metal ions, the dodecamers "stack" along their six-fold axis of symmetry to yield elongated tubes. This self-assembly process provides a useful model for p... |
10488140 | Apolipoprotein A-I stimulates secretion of apolipoprotein E by foam cell macrophages. | Apolipoprotein A-I (apoA-I) overexpression inhibits atherogenesis in mice, and apolipoprotein E (apoE) secreted by foam cell macrophages may exert antiatherogenic effects within the arterial wall. We hypothesized that interaction between apoA-I and apoE contributed to the antiatherogenic properties of apoA-I, and there... |
10488135 | Oligomerization of the UvrB nucleotide excision repair protein of Escherichia coli. | A combination of hydrodynamic and cross-linking studies were used to investigate self-assembly of the Escherichia coli DNA repair protein UvrB. Though the procession of steps leading to incision of DNA at sites flanking damage requires that UvrB engage in an ordered series of complexes, successively with UvrA, DNA, and... |
10486439 | Influence of cyclodextrins on the stability of the peptide salmon calcitonin in aqueous solution. | The influence of beta-cyclodextrin (betaCD), and various betaCD derivatives, on both the chemical and the physical stability of the polypeptide hormone salmon calcitonin (sCT) in aqueous solutions was investigated at elevated temperature (55 degrees C). Also, the influence of various betaCD derivatives on the enzymatic... |
10486436 | Synthesis and characterisation of palymitoyl propanolol hydrochloride auto-lymphotrophs for oral administration. | Self-associating supramolecular organisation of molecules above critical micellar concentrations (c.m.c.) offers enormous potentials in figuring distinguished behaviour both within formulations as well as in the bioenvironment. The present study deals with the enhancement of the oral bioavailability of propranolol HCl ... |
10487762 | NuA4, an essential transcription adaptor/histone H4 acetyltransferase complex containing Esa1p and the ATM-related cofactor Tra1p. | Post-translational acetylation of histone H4 N-terminal tail in chromatin has been associated with several nuclear processes including transcription. We report the purification and characterization of a native multisubunit complex (NuA4) from yeast that acetylates nucleosomal histone H4. NuA4 has an apparent molecular ... |
10487755 | Crystal structure of an IRF-DNA complex reveals novel DNA recognition and cooperative binding to a tandem repeat of core sequences. | There has been growing interest in the role of the IRF (interferon regulatory factor) family of transcription factors in the regulation of immune responses, cytokine signaling, and oncogenesis. These members are characterized by their well-conserved DNA binding domains at the N-terminal regions. Here we report the 2.2 ... |
10485884 | Site-directed disulfide bonding reveals an interaction site between energy-coupling protein TonB and BtuB, the outer membrane cobalamin transporter. | Transport of vitamin B(12) across the outer membrane of Escherichia coli, like that of iron-siderophore complexes, is an active transport process requiring a specific outer membrane transporter BtuB, the proton motive force, and the trans-periplasmic energy coupling protein TonB. Interaction between TonB and two of the... |
10485874 | A DNA pentaplex incorporating nucleobase quintets. | Supramolecular self-assembly is an integral step in the formation of many biological structures. Here we report a DNA pentaplex that derives from a metal-assisted, hydrogen bond-mediated self-assembly process. In particular, cesium ions are found to induce pentameric assembly of DNA bearing the nonstandard nucleobase i... |
10485872 | Padlock oligonucleotides for duplex DNA based on sequence-specific triple helix formation. | An oligonucleotide was circularized around double-stranded DNA thanks to triple helix formation. Short oligonucleotides are known to be able to form DNA triple helices by binding into the DNA major groove at an oligopurine.oligopyrimidine sequence. After sequence-specific recognition of a double-stranded DNA target thr... |
10484608 | Apolipoprotein E-dependent cholesterol efflux from macrophages: kinetic study and divergent mechanisms for endogenous versus exogenous apolipoprotein E. | In these studies, we have utilized a J774 macrophage model in order to compare phospholipid and cholesterol efflux kinetics in macrophage cells that do not express endogenous apoE to cells transfected to express physiologic levels of human apoE. This model was also used to compare the effect of exogenously added versus... |
10483357 | Control of photoinduced electron transfer from zinc-porphyrin to methyl viologen by supramolecular formation between monoclonal antibody and zinc-porphyrin. | Photoinduced electron transfer from tetrakis(4-carboxy-phenyl porphyrin)-zinc complex (Zn-TCPP) to an acceptor molecule (methyl viologen; MV2+) has been found to be controlled by the complex formation of monoclonal antibody 03-1 for the porphyrin (TCPP) and Zn-TCPP. Although there are no ground-state interactions betwe... |
10479359 | Solubilization of flavopiridol by pH control combined with cosolvents, surfactants, or complexants. | This study investigates the roles of both ionized and un-ionized species of flavopiridol in solubilization by complexation, micellization, and cosolvency. Control of pH was used in combination with surfactants (polysorbate 20 and polysorbate 80), cosolvents (ethanol and propylene glycol), as well as uncharged and anion... |
10479352 | Hydroxypropyl-beta-cyclodextrin inhibits spray-drying-induced inactivation of beta-galactosidase. | The single-step, fast spray-drying process may represent a valuable alternative to the multistep, time-consuming freeze-drying process in the area of formulation and processing of biopharmaceuticals. In this study, we tested the use of sucrose and hydroxypropyl-beta-cyclodextrin (HP-beta-CD) as stabilizing excipients i... |
10479350 | Improvement in solubility and dissolution rate of 1, 2-dithiole-3-thiones upon complexation with beta-cyclodextrin and its hydroxypropyl and sulfobutyl ether-7 derivatives. | Inclusion complexes between beta-cyclodextrin derivatives and 1, 2-dithione-3-thiones were studied in aqueous solution and in the solid state. Phase solubility study was used to evaluate the complexation in solution, at 37 degrees C, of three cyclodextrins, i. e., beta-cyclodextrin (betaCD), hydroxypropyl-beta-cyclodex... |
10480890 | Direct kinetic evidence for folding via a highly compact, misfolded state. | The 2 S seed storage protein, sunflower albumin 8 (SFA-8), contains an unusually high proportion of hydrophobic residues including 16 methionines (some of which may form a surface hydrophobic patch) in a disulfide cross-linked, alpha-helical structure. Circular dichroism and fluorescence spectroscopy show that SFA-8 is... |
10477314 | Role of alpha(v) integrins in adenovirus cell entry and gene delivery. | Adenoviruses (Ad) are a significant cause of acute infections in humans; however, replication-defective forms of this virus are currently under investigation for human gene therapy. Approximately 20 to 25% of all the gene therapy trials (phases I to III) conducted over the past 10 years involve the use of Ad gene deliv... |
10477284 | Editing of non-cognate aminoacyl adenylates by peptide synthetases. | Non-ribosomally formed peptides display both highly conserved and variable amino acid positions, the variations leading to a wide range of peptide families. Activation of the amino acid substrate proceeds in analogy to the ribosomal biosynthetic mechanism generating aminoacyl adenylate and acyl intermediates. To approa... |
10477271 | Characterization and polyanion-binding properties of purified recombinant prion protein. | Certain polysulphated polyanions have been shown to have prophylactic effects on the progression of transmissible spongiform encephalopathy disease, presumably because they bind to prion protein (PrP). Until now, the difficulty of obtaining large quantities of native PrP has precluded detailed studies of these interact... |
10471934 | Antibody recognition imaging by force microscopy. | We have developed a method that combines dynamic force microscopy with the simultaneous molecular recognition of an antigen by an antibody, during imaging. A magnetically oscillated atomic force microscopy tip carrying a tethered antibody was scanned over a surface to which lysozyme was bound. By oscillating the probe ... |
10471730 | Transfer RNA identity contributes to transition state stabilization during aminoacyl-tRNA synthesis. | Sequence-specific interactions between aminoacyl-tRNA synthetases and their cognate tRNAs ensure both accurate RNA recognition and the efficient catalysis of aminoacylation. The effects of tRNA(Trp)variants on the aminoacylation reaction catalyzed by wild-type Escherichia coli tryptophanyl-tRNA synthe-tase (TrpRS) have... |
10473583 | Crystal structure of a maltogenic amylase provides insights into a catalytic versatility. | Amylases catalyze the hydrolysis of starch material and play central roles in carbohydrate metabolism. Compared with many different amylases that are able to hydrolyze only alpha-D-(1,4)-glycosidic bonds, maltogenic amylases exhibit catalytic versatility: hydrolysis of alpha-D-(1,4)- and alpha-D-(1,6)-glycosidic bonds ... |
10471702 | Genetic study of interactions between the cytoskeletal assembly protein sla1 and prion-forming domain of the release factor Sup35 (eRF3) in Saccharomyces cerevisiae. | Striking similarities between cytoskeletal assembly and the "nucleated polymerization" model of prion propagation suggest that similar or overlapping sets of proteins may assist in both processes. We show that the C-terminal domain of the yeast cytoskeletal assembly protein Sla1 (Sla1C) specifically interacts with the ... |
10471821 | Chiral DNA packaging in DNA-cationic liposome assemblies. | Recent studies have indicated that the structural features of DNA-lipid assemblies, dictated by the lipid composition and cationic lipid-to-DNA ratio, critically affect the efficiency of these complexes in acting as vehicles for cellular delivery of genetic material. Using circular dichroism we find that upon binding D... |
10471678 | Aptamers: an emerging class of molecules that rival antibodies in diagnostics. | Antibodies, the most popular class of molecules providing molecular recognition needs for a wide range of applications, have been around for more than three decades. As a result, antibodies have made substantial contributions toward the advancement of diagnostic assays and have become indispensable in most diagnostic t... |
10473430 | Expression of the isoamylase gene of Flavobacterium odoratum KU in Escherichia coli and identification of essential residues of the enzyme by site-directed mutagenesis. | The isoamylase gene from Flavobacterium odoratum KU was cloned into and expressed in Escherichia coli JM109. The promoter of the gene was successful in E. coli, and the enzyme produced was excreted into the culture medium, depending on the amount of the enzyme expressed. The enzyme found in the culture medium showed al... |
10473427 | Enhanced (+)-catechin transglucosylating activity of Streptococcus mutans GS-5 glucosyltransferase-D due to fructose removal. | The (+)-catechin transglucosylating activities of several glucosyltransferases (GTFs) from the genus Streptococcus were compared. For this purpose, a mixture of four GTFs from Streptococcus sobrinus SL-1 and recombinant GTF-B and GTF-D from Streptococcus mutans GS-5 expressed in Escherichia coli were studied. It was sh... |
10471557 | Sulfonamide resistance in clinical isolates of Campylobacter jejuni: mutational changes in the chromosomal dihydropteroate synthase. | The characterization of the genetic basis of sulfonamide resistance in Campylobacter jejuni was attempted. The resistance determinant from a sulfonamide-resistant strain of C. jejuni was cloned and was found to show 42% identity with the folP gene (which codes for dihydropteroate synthase, the target of sulfonamides) o... |
10469727 | Localization of the K+ lock-In and the Ba2+ binding sites in a voltage-gated calcium-modulated channel. Implications for survival of K+ permeability. | Using Ba2+ as a probe, we performed a detailed characterization of an external K+ binding site located in the pore of a large conductance Ca2+-activated K+ (BKCa) channel from skeletal muscle incorporated into planar lipid bilayers. Internal Ba2+ blocks BKCa channels and decreasing external K+ using a K+ chelator, (+)-... |
10471335 | Fine structure of the developing avian corneal stroma as revealed by quick-freeze, deep-etch electron microscopy. | Corneal transparency depends on the precise organization of the stromal extracellular matrix. The morphology of the extracellular matrix of the embryonic and adult avian secondary posterior cornea was studied in glutaraldehyde-fixed, quick-frozen, deep-etched replicas with the electron microscope. Although the collagen... |
10469648 | Early nuclear events in plant defence signalling: rapid gene activation by WRKY transcription factors. | Parsley WRKY proteins comprise a family of plant-specific zinc-finger-type factors implicated in the regulation of genes associated with pathogen defence. In vitro, these proteins bind specifically to functionally defined TGAC-containing W box promoter elements within the Pathogenesis-Related Class10 (PR-10) genes. Her... |
10469642 | Phosphorylase recognition and phosphorolysis of its oligosaccharide substrate: answers to a long outstanding question. | Phosphorylases are key enzymes of carbohydrate metabolism. Structural studies have provided explanations for almost all features of control and substrate recognition of phosphorylase but one question remains unanswered. How does phosphorylase recognize and cleave an oligosaccharide substrate? To answer this question we... |
10467166 | Azide- and cyanide-binding to the Escherichia coli bd-type ubiquinol oxidase studied by visible absorption, EPR and FTIR spectroscopies. | Cytochrome bd-type ubiquinol oxidase contains two hemes b (b(558) and b(595)) and one heme d as the redox metal centers. To clarify the structure of the reaction center, we analyzed Escherichia coli cytochrome bd by visible absorption, EPR and FTIR spectroscopies using azide and cyanide as monitoring probes for the exo... |
10465779 | The second derivative electronic absorption spectrum of cytochrome c oxidase in the Soret region. | The electronic absorption spectrum of solubilized beef heart cytochrome c oxidase was analyzed in the 400-500 nm region to identify the origin of doublet features appearing in the second derivative spectrum associated with ferrocytochrome a. This doublet, centered near 22,600 cm(-1), was observed in the direct absorpti... |
10465770 | vpu transmembrane peptide structure obtained by site-specific fourier transform infrared dichroism and global molecular dynamics searching. | The recently developed method of site-directed Fourier transform infrared dichroism for obtaining orientational constraints of oriented polymers is applied here to the transmembrane domain of the vpu protein from the human immunodeficiency virus type 1 (HIV-1). The infrared spectra of the 31-residue-long vpu peptide re... |
10465760 | Comparison of the biophysical properties of racemic and d-erythro-N-acyl sphingomyelins. | In this study stereochemically pure d-erythro-sphingomyelins (SMs) with either 16:0 or 18:1(cisDelta9) as the N-linked acyl-chain were synthesized. Our purpose was to examine the properties of these sphingomyelins and acyl-chain matched racemic (d-erythro/l-threo) sphingomyelins in model membranes. Liquid-expanded d-er... |
10465756 | Polymer-cushioned bilayers. II. An investigation of interaction forces and fusion using the surface forces apparatus. | We have created phospholipid bilayers supported on soft polymer "cushions" which act as deformable substrates (see accompanying paper, Wong, J. Y., J. Majewski, M. Seitz, C. K. Park, J. N. Israelachvili, and G. S. Smith. 1999. Biophys. J. 77:1445-1457). In contrast to "solid-supported" membranes, such "soft-supported" ... |
10464206 | Direct probing of the surface ultrastructure and molecular interactions of dormant and germinating spores of Phanerochaete chrysosporium. | Atomic force microscopy (AFM) has been used to probe, under physiological conditions, the surface ultrastructure and molecular interactions of spores of the filamentous fungus Phanerochaete chrysosporium. High-resolution images revealed that the surface of dormant spores was uniformly covered with rodlets having a peri... |
10464196 | The Cpx envelope stress response is controlled by amplification and feedback inhibition. | In Escherichia coli, the Cpx two-component regulatory system activates expression of protein folding and degrading factors in response to misfolded proteins in the bacterial envelope (inner membrane, periplasm, and outer membrane). It is comprised of the histidine kinase CpxA and the response regulator CpxR. This respo... |
10460252 | Regulation of mitogen-activated protein kinases by sphingolipid products in oligodendrocytes. | Sphingolipid products such as ceramide (cer), sphingosine (sph), and sphingosine-1-phosphate (SPP) are implicated in the regulation of cell growth and apoptosis. We have recently shown that cer, sph, and SPP differentially modulate ionic events in cultured oligodendrocytes (OLGs). Cer but not sph or SPP inhibits the in... |
10456943 | Control of filament formation in Candida albicans by polyamine levels. | Candida albicans, the most common fungal pathogen, regulates its cellular morphology in response to environmental conditions. The ODC gene, which encodes ornithine decarboxylase, a key enzyme in polyamine biosynthesis, was isolated and disrupted. Homozygous null Candida mutants behaved as polyamine auxotrophs and grew ... |
10455032 | Characterization of a flavocytochrome that is induced during the anaerobic respiration of Fe3+ by Shewanella frigidimarina NCIMB400. | A 63.9 kDa periplasmic tetrahaem flavocytochrome c(3), designated Ifc(3), was found to be expressed in Shewanella frigidimarina NCIMB400 grown anaerobically with ferric citrate or ferric pyrophosphate as the sole terminal electron acceptor, but not in anaerobic cultures of the bacterium with other respiratory substrate... |
10455014 | Large-scale production and purification of functional recombinant bovine rhodopsin with the use of the baculovirus expression system. | Here we describe a generic procedure for the expression and purification of milligram quantities of functional recombinant eukaryotic integral membrane proteins, exemplified by hexahistidine-tagged bovine rhodopsin. These quantities were obtained with the recombinant baculovirus/Sf9 insect cell-based expression system ... |
10454533 | Dual role for Hsc70 in the biogenesis and regulation of the heme-regulated kinase of the alpha subunit of eukaryotic translation initiation factor 2. | The heme-regulated kinase of the alpha subunit of eukaryotic initiation factor 2 (HRI) is activated in rabbit reticulocyte lysate (RRL) in response to a number of environmental conditions, including heme deficiency, heat shock, and oxidative stress. Activation of HRI causes an arrest of initiation of protein synthesis.... |
10454496 | Comparative pharmacology of the nonpeptide neuromedin B receptor antagonist PD 168368. | The mammalian peptide neuromedin B (NMB) and its receptor are expressed in a variety of tissues; however, little is definitively established about its physiological actions because of the lack of potent, specific antagonists. Recently, the peptoid PD 168368 was found to be a potent human NMB receptor antagonist. Becaus... |
10446241 | A novel potent strategy for gene delivery using a single peptide vector as a carrier. | We have shown previously that a peptide, MPG, derived from the hydrophobic fusion peptide of HIV-1 gp41 and the hydrophilic nuclear localisation sequence of SV40 large T antigen, can be used as a powerful tool for the delivery of oligonucleotides into cultured cells. Now we extend the potential of MPG to the delivery o... |
10446235 | Isolation of altered specificity mutants of the single-chain 434 repressor that recognize asymmetric DNA sequences containing the TTAA and TTAC subsites. | A novel single-chain (sc) protein framework containing covalently dimerized DNA-binding domains (DBD) of the phage 434 repressor was used to construct combinatorial mutant libraries in order to isolate mutant DBDs with altered specificities. The library members contain one wild-type DBD and one mutant domain with rando... |
10438836 | Association of influenza virus matrix protein with ribonucleoproteins. | To characterize the sites and nature of binding of influenza A virus matrix protein (M1) to ribonucleoprotein (RNP), M1 of A/WSN/33 was altered by deletion or site-directed mutagenesis, expressed in vitro, and allowed to attach to RNP under a variety of conditions. Approximately 70% of the wild-type (Wt) M1 bound to RN... |
10438819 | Characterization of the oriI and oriII origins of replication in phage-plasmid P4. | In the Escherichia coli phage-plasmid P4, two partially overlapping replicons with bipartite ori sites coexist. The essential components of the oriI replicon are the alpha and cnr genes and the ori1 and crr sites; the oriII replicon is composed of the alpha gene, with the internal ori2 site, and the crr region. The P4 ... |
10438805 | Regulation of human papillomavirus type 31 polyadenylation during the differentiation-dependent life cycle. | The L1 and L2 capsid genes of human papillomavirus type 31 (HPV-31) are expressed late in the differentiation-dependent life cycle from a promoter located in the E7 open reading frame (ORF) of the early region. These late HPV genes are transcribed by RNA polymerase II which reads through the region containing early pol... |
35790094 | Acyl-Hydrazide Derivatives of a Xanthine Carboxylic Congener (XCC) as Selective Antagonists at Human A<sub>2B</sub> Adenosine Receptors. | The structure-activity relationships (SAR) of 8-phenyl-1,3-dipropylxanthine derivatives in binding to recombinant human A<sub>2B</sub> adenosine receptors were explored, in order to identify selective antagonists. Based on the finding of receptor selectivity in MRS 1204, containing an N-hydroxysuccinimide ester attache... |
25132724 | Feasibility of measuring antigen-antibody interaction forces using a scanning force microscope. | The molecular affinity scanning force microscopy (MASFM) described in this study was developed in an effort to test the possibility of antigen-antibody binding measurement using force-separation distance profiles. The MASFM configuration was comprised of a spherical glass bead as an MASFM probe, to which the fluorescei... |
21662903 | A Calixarene-Based Fluorogenic Reagent for Selective Mercury(II) Recognition. | The first calixarene-based fluorogenic Hg(II)-selective extractant, 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,27-bis(N-(5-dimethylaminonaphthalene-1-sulfonyl)carbamoylmethoxy)-26,28-dimethoxycalix[4]arene (2), is reported. In solvent extraction from aqueous acidic solutions (HNO(3)), 2 exhibits excellent selectivity fo... |
18967691 | Determination of the cyclodextrin inclusion constant with the constant current coulometric titration method. | With fluorometry this paper has proved that alpha-cyclodextrin (CD) and gamma-CD do not form inclusion complexes with procaine, while beta-CD and HP-beta-CD do. Their molar ratios are demonstrated both 1:1 with the equimolar variation method. The constant current coulometric titration method (CCCT) is first proposed an... |
10927400 | Crystal engineering using bisphenols and trisphenols. Complexes with 1,10-phenanthroline: hydrogen-bonded chains in adducts with 4,4'-biphenol (1/1) and 4,4'-sulfonyldiphenol (2/3), pi-pi stacked chains in the (1/2) adduct with 4,4'-thiodiphenol, and pairwise-interwoven nets in 1,1,1-tris(4-hydroxyphenyl)ethane-1,10-ph... | In 4,4'-biphenol-1,10-phenanthroline (1/1) [systematic name: 4,4'-biphenyldiol-1,10-phenanthroline (1/1)] the diphenol molecules lie across centres of inversion and the phenanthroline molecules lie across twofold rotation axes; the phenanthroline molecules act as chain-building units and the molecular components are li... |
10837761 | Application of membrane-active peptides for nonviral gene delivery. | A variety of membrane-modifying agents including pH-specific fusogenic or lytic peptides, bacterial proteins, lipids, glycerol, or inactivated virus particles have been evaluated for the enhancement of DNA-polycation complex-based gene transfer. The enhancement depends on the characteristics of both the cationic carrie... |
10458816 | Macrolide Analogues of the Novel Immunosuppressant Sanglifehrin: New Application of the Ring-Closing Metathesis Reaction. | Macrocycles containing a conjugated 1,3-diene moiety have been synthesized for the first time in good yields by the ring-closing metathesis reaction [Eq. (1)]. The new compounds represent cyclophilin-binding, simplified analogues of the macrocyclic core of sanglifehrin A, an immunosuppressant which binds with high affi... |
10458813 | Resolution of Racemic 1,2-Dibromohexafluoropropane through Halogen-Bonded Supramolecular Helices. | Halogen bonds, attractive intermolecular interactions between perfluoroalkyl bromides and bromide ions, are present in cocrystals of (-)-sparteinium hydrobromide (1) and (S)-1,2-dibromohexafluoropropane (2; shown schematically), and result in enantiopure and infinite supramolecular helices. The perfluorocarbon-hydrocar... |
10458802 | Self-Assembling Supramolecular Nanostructures from a C(60) Derivative: Nanorods and Vesicles. | Simple modification of solution conditions provides facile access to supramolecular fullerene nanostructures. The fullerene derivative shown self-assembles to give nanorods or vesicles. The nanorods have diameters of 10-250 nm, depending on the counterion, and lengths greater than 70 µm. If ultrasonication is used, no ... |
10458796 | Functionalizable Alkylidenes: Tungsten Complexes of Phosphanyl-, Amino-, Alkynyl-, and Tinalkylidenes and Their Dimetallic Derivatization. | The introduction of a heteroatom at the alkylidene carbon atom of calixarene complexes such as 1 results in an organometallic compound that shows properties of both Fischer carbenes and Schrock alkylidenes. Such modified alkylidenes allow access to dimetallic alkylidene complexes. For example, 1 reacts with [CuCOCl] to... |
10458792 | Supramolecular Sensors for the Detection of Alcohols. | Cooperativity between different noncovalent host-guest interactions is the key for the successful generation of selective supramolecular sensors. A new class of cavitands capable of synergistic CH small middle dot small middle dot small middle dotpi interactions and hydrogen bonding has been designed and exploited for ... |
10458787 | Self-Assembly of a Tetrahedral Lectin into Predesigned Diamondlike Protein Crystals. | Binding sites analogous to those of sp(3) carbon are presented by concanavalin A. This lectin has now been cross-linked with a bismannopyranoside which contains the C(2) spacer required to form the computer-modeled diamondlike three-dimensional protein lattice shown in the picture. |
10446047 | Controlling molecular self-organization: formation of nanometer-scale spheres and tubules | Amphiphilic polyhedron-shaped p-sulfonatocalix[4]arene building blocks, which have been previously shown to assemble into bilayers in an antiparallel fashion, have been assembled in a parallel alignment into spherical and helical tubular structures by the addition of pyridine N-oxide and lanthanide ions. Crystallograph... |
10425505 | Tuning of Magnetic Anisotropy in Hexairon(III) Rings by Host-Guest Interactions: An Investigation by High-Field Torque Magnetometry. | Full chemical control of magnetic anisotropy in hexairon(III) rings can be achieved by varying the size of the guest alkali metal ion. Dramatically different anisotropies characterize the Li(I) and Na(I) complexes of [Fe(6)(OMe)(12)(L)(6)] (L=1,3-propanedione derivatives; a schematic representation of the Li(I) complex... |
10425499 | Surface-Confined Metallodendrimers: Isolated Nanosize Molecules. | The incorporation of dialkyl sulfide side chains in metallodendrimers is a simple method for their insertion into a monolayer of decanethiol formed by self-assembly on a gold surface. The dendrimer binds through the sulfide group to a defect in the monolayer on the gold surface (see picture). The surface concentration ... |
10425490 | Supramolecular Complexation of Polynuclear Aqua Ions: A Crown Ether Adduct of a µ-Oxo-Bridged Iron(III) Aqua Dimer. | Hydrolysis and polymerization of [Fe(OH(2))(6)](3+) in aqueous solution leads, in the early stages, to the oxo-bridged binuclear aqua ion [(H(2)O)(5)Fe(µ-O)Fe(OH(2))(5)](4+), which could be obtained in crystalline form through the use of [18]crown-6. The complex exhibits an almost linear Fe-O-Fe moiety and antiferromag... |
10425476 | Supramolecular Structure of Precipitated Nanosize beta-Carotene Particles. | A combination of analytical methods and molecular modeling calculations has provided a detailed picture of the supramolecular and microscopic structure of precipitated lipophilic carotenoids. The nanoparticles have a core/shell structure (see schematic representation) in which the particle core (120 nm) consists of a v... |
10421730 | Hyperbranched Polymers and Aggregates: Distribution Kinetics of Dendrimer Growth. | We present an analytic solution for growth of branched aggregates or polymers with distributed cluster (dendrimer) size. Monomer addition to each branch follows first-order polymerization kinetics leading to a distribution of branch lengths. The rate constant for monomer addition is considered diffusion-dependent. Dete... |
10395773 | Role of Hydrophobic Effect on the Noncovalent Interactions Between Salicylic Acid and a Series of beta-Cyclodextrins. | The molecular complexation of salicylic acid (o-hydroxybenzoic acid) by beta-cyclodextrin (beta-CD) and/or two of its most used derivatives, 2,6-di-O-methyl-beta-cyclodextrin (DIMEB) and hydroxypropyl-beta-cyclodextrin (HPBCD), was studied from pH potentiometric measurements. The role of the hydrophobic effect was eval... |
15818975 | [Study on the determination of trace caesium in bittern by extraction separation graphite furnace atomic absorption spectrometry]. | The atomizatiom behavior of Cs in bittern and the mechanism were studied by graphite furnace atomic absorption spectrometry. Interferences of inorganic acid from the bittern on absorption signal of Cs were examined. It is shown that there are gaseous interferences and molecular absorption interferences and ionization i... |
15818960 | [Spectroscopic study on procaine hydrochloride and its cyclodextrins inclusion complexes]. | In this paper, by means of the ultraviolet spectrum of procaine, we showed the existence of two types of procaine (molecular and ion types) and determined their pH values. The variations of fluorescence intensity of the two types in the presence or absence beta-CD, HP-beta-CD and Methyl-beta-CD were studied. |
11969980 | Microscopic basis of free-volume concept as studied by quasielastic neutron scattering and positron annihilation lifetime spectroscopy. | We have reexamined the free-volume concept presented by Cohen and Turnbull on the basis of two microscopic quantities: the excess mean-square displacement <u(2)>(f) and the total free volume V(PA,t), of poly- butadiene evaluated from the quasielastic neutron scattering and the positron annihilation lifetime spectroscop... |
10822581 | Modular nucleic acid surrogates. Solid phase synthesis of alpha-helical peptide nucleic acids (alpha PNAs). | [formula: see text] The synthesis and characterization of prototype alpha-helical peptide nucleic acid (alpha PNA) modules 1-3 as well as disulfide dimers 4 and 5 are reported. These molecules combine an alpha-helical peptidyl scaffold with well-defined nucleobase molecular recognition patterns and could serve as a bas... |
10694940 | Alpha E beta 7. | alpha E beta 7 is a member of the integrin family and is expressed almost exclusively by cells of the T lymphocyte lineage in mucosal tissues. Expression is induced by transforming growth factor beta in the mucosal microenvironment. Genetic elements that control transcription are under investigation and may prove valua... |
10552622 | Structure elucidation, enantioselective analysis, and biogenesis of nerol oxide in Pelargonium species. | A novel enantioselective synthesis of nerol oxide (3, 6-dihydro-4-methyl-2-(2-methyl-1-propenyl)-2H-pyran) was used for the determination of the absolute configuration at C-2. The order of elution of the enantiomers on octakis-(2, 3-di-O-butyryl-6-O-tert-butyldimethylsilyl)-gamma-cyclodextrin in OV 1701-vi as the chira... |
10552607 | Biogenetic studies in Mentha x piperita. 1. deuterium-labeled monoterpene ketones: synthesis and stereoselective analysis. | Pulegone, menthone, and isomenthone isotopomers are synthesized as regioselectively deuterated d(5)- and d(8)-stereoisomers. Deuterium-labeled menthone and isomenthone enantiomers are analyzed using enantioselective multidimensional gas chromatography/mass spectrometry. The deuterated stereoisomers of menthone and isom... |
10518990 | Intermediate filament assembly: temperature sensitivity and polymorphism. | Intermediate filament (IF) proteins are encoded by a large multigene family and form polymers with a uniform diameter of approximately 10 nm. However, although the cytoplasmic representatives all confirm to a unit-type structural principle leading to the formation of extended coiled coils, it is becoming increasingly c... |
10510792 | Charged cyclodextrin-mediated sample stacking in micellar capillary electrophoresis. A simple method for enhancing the detection sensitivity of hydrophobic compounds. | The development of on-line sample stacking techniques for enhancing limits of detection of neutral analytes in micellar capillary electrophoresis (MCE) has recently gained much attention. Utilizing high-conductivity sample matrices to invoke sample stacking is promising, but requires the limited use of sample solubiliz... |
10510771 | Non-aqueous capillary electrophoresis chiral separations with sulfated beta-cyclodextrin. | This paper reports the application of an anionic cyclodextrin (CD), sulfated beta-cyclodextrin with a degree of substitution of four (beta-CD-(SO4-)4, in chiral separations of pharmaceutical enantiomers by non-aqueous capillary electrophoresis (NACE). Upon complexation with the anionic CD, electrophoretic mobilities of... |
10497879 | Binding and signalling properties of a growth hormone enhancing monoclonal antibody. | We have used a sequential, qualitative biosensor based assay to demonstrate that OA15, a monoclonal antibody which enhances in vivo the activity of bovine growth hormone (bGH) does not disrupt the interaction between bGH and its cognate receptor (as represented by recombinant bovine GH binding protein -rbGHBP). We have... |
10486754 | Separation of antipsychotic drugs (clozapine, loxapine) and their metabolites by capillary zone electrophoresis. | Two antipsychotic drugs (clozapine and loxapine) and six metabolites, N-demethylclozapine, clozapine N-oxide, N-demethylloxapine (amoxapine), 7-hydroxyloxapine, 8-hydroxyloxapine, 8-hydroxyamoxapine, were separated by capillary zone electrophoresis. Variation of pH and ionic strength of the acidic phosphate buffer (pH ... |
10486753 | Resolution of newly synthesized racemic dihydropyridines with different chiral selectors by means of capillary electrophoresis. | The racemates of newly synthesized 4-aryl-1,4-dihydropyridine derivatives attracting interest in the treatment of coronary insufficience were resolved via the formation of diastereomeric salts. In order to check the quality of the preparative resolution, capillary electrophoresis using neutral cyclodextrins (CDs) was d... |
10486751 | Cyclodextrin-mediated micellar electrokinetic chromatography and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for the enantiomer separation of racemorphan in human urine. | Micellar electrokinetic chromatography (MEKC) was successfully and conveniently applied to the chiral separation with the addition of cyclodextrins (CDs) as chiral selector to the running buffer. Chiral separation depended on the type of CD; in particular, beta-CD was effective for the chiral separation of racemorphan.... |
10486748 | Highly-sensitive micellar electrokinetic chromatographic analysis of dioxin-related compounds using on-line concentration. | An application study of an on-line concentration technique of neutral analytes for micellar electrokinetic chromatography (MEKC) was carried out in environmental analysis to enhance the UV detection sensitivity. Several dioxins and related compounds, such as dibenzofuran, dibenzo-p-dioxin, 2,3- and 2,7-dichlorodibenzo-... |
10486721 | Chiral separations by open tubular capillary electrokinetic chromatography. | The inner walls of 50 microns fused-silica capillaries are etched by ammonium hydrogendifluoride and then modified by the silanization/hydrosilation method with a chiral selector. Three different types of selectors were evaluated: lactone, beta-cyclodextrin and naphthylethylamine. Each of the bonded chiral stationary p... |
10483673 | Multiple organ failure and prognosis in adult patients with diabetic ketoacidosis. | <h4>Objective</h4>Evaluation of prognostic factors of patients presenting with diabetic ketoacidosis (DKA) at an emergency department.<h4>Design</h4>Retrospective cohort study.<h4>Setting</h4>The Emergency Department of the Vienna General Hospital, a 2000-bed tertiary care hospital.<h4>Patients and participants</h4>Pat... |
10479615 | Surface processes in the crystallization of turnip yellow mosaic virus visualized by atomic force microscopy. | In situ atomic force microscopy (AFM) was used to investigate surface evolution during the growth of single crystals of turnip yellow mosaic virus (TYMV). Growth of the (101) face of TYMV crystals proceeded by two-dimensional nucleation. The molecular structure of the step edges and adsorption of individual virus parti... |
10481989 | Alkyl nitrates as achiral and chiral solute probes in gas chromatography. Novel properties of a beta-cyclodextrin derivative and characterization of its enantioselective forces. | Achiral and chiral interactions of alkyl nitrates (R-O-NO2) with heptakis-(3-O-acetyl-2,6-di-O-pentyl)-beta-cyclodextrin (LIPODEX-D) in the gas phase were investigated chromatographically. Two major outcomes can be summarized. First, LIPODEX-D shows very fast temperature-dependent variations of the selectivity up to ch... |
10481979 | Isolation and characterization of cyclic alpha-(1-->4)-glucans having degrees of polymerization 9-31 and their quantitative analysis by high-performance anion-exchange chromatography with pulsed amperometric detection. | Cyclic alpha-(1-->4)-glucans with degrees of polymerization (DPs) 9-31 were isolated from a mixture of cyclization products formed in the early stage of the action of cyclodextrin glucanotransferase (CGTase) on synthetic amylose, and characterized by matrix-assisted laser desorption ionization time-of-flight MS, 13C-NM... |
10481915 | Epigenetic spreading of the Drosophila dosage compensation complex from roX RNA genes into flanking chromatin. | The multisubunit MSL dosage compensation complex binds to hundreds of sites along the Drosophila single male X chromosome, mediating its hypertranscription. The male X chromosome is also coated with noncoding roX RNAs. When either msl3, mle, or mof is mutant, a partial MSL complex is bound at only approximately 35 unus... |
10480338 | Galectins-1 and -3 and their ligands in tumor biology. Non-uniform properties in cell-surface presentation and modulation of adhesion to matrix glycoproteins for various tumor cell lines, in biodistribution of free and liposome-bound galectins and in their expression by breast and colorectal carcinomas with/without met... | Protein (lectin)-carbohydrate (cellular glycoconjugate) recognition is operative in biochemical information transfer. Galectins constitute a family of endogenous galactoside-binding lectins with conserved features in the binding site. The members of this lectin category are assumed to be involved in cell adhesion and g... |
10480241 | Affinity chromatography of human estrogen receptor-alpha expressed in Saccharomyces cerevisiae. Combination of heparin- and 17beta-estradiol-affinity chromatography. | Estrogen receptor-alpha is a member of the nuclear hormone receptor superfamily and is considered as a very important regulatory protein. Human estrogen receptor-alpha has been cloned into Saccharomyces cerevisiae as a fusion to ubiquitin and expression is controlled by a metallothionin promotor. Pilot scale quantities... |
10480226 | Retention behavior of very large biomolecules in ion-exchange chromatography. | Hepatitis B virus surface antigen (HBsAg) particles were efficiently adsorbed (retained) on a Sulfate-cellulose (S-C) bead column, and then desorbed with sodium chloride solutions (0.5-3.0 M). The HBsAg particles were not efficiently retained onto either sulfopropyl-agarose (SP-A) or quaternary amine-agarose (Q-A) at p... |
10475958 | Molecular recognition specificity of Bacillus anthracis spore antibodies. | The sensitivity and specificity of polyclonal and monoclonal antibodies raised against anthrax spore preparations has been assessed by Western blotting. None of the antibodies studied were completely specific in recognizing the anthrax spore surface. A polyclonal serum recognized a wide range of spore surface epitopes ... |
10467148 | Coagulation factor IXa: the relaxed conformation of Tyr99 blocks substrate binding. | <h4>Background</h4>Among the S1 family of serine proteinases, the blood coagulation factor IXa (fIXa) is uniquely inefficient against synthetic peptide substrates. Mutagenesis studies show that a loop of residues at the S2-S4 substrate-binding cleft (the 99-loop) contributes to the low efficiency. The crystal structure... |
10475560 | Autonomic neuropeptides in the interface membrane of aseptic loose hip prostheses. | We analyzed the presence of autonomic nerve fibers in the interface membranes (n = 9) surrounding aseptic loosened hip prostheses by immunohistochemistry. The study focused on the autonomic messengers neuropeptide Y (NPY), tyrosine hydroxylase (TH), the rate-limiting enzyme in the synthesis of noradrenaline (NA), and v... |
10469824 | Automated docking of peptides and proteins by using a genetic algorithm combined with a tabu search. | A genetic algorithm (GA) combined with a tabu search (TA) has been applied as a minimization method to rake the appropriate associated sites for some biomolecular systems. In our docking procedure, surface complementarity and energetic complementarity of a ligand with its receptor have been considered separately in a t... |
10468562 | Crystal structure of triosephosphate isomerase from Trypanosoma cruzi in hexane. | To gain insight into the mechanisms of enzyme catalysis in organic solvents, the x-ray structure of some monomeric enzymes in organic solvents was determined. However, it remained to be explored whether the structure of oligomeric proteins is also amenable to such analysis. The field acquired new perspectives when it w... |
10468561 | Mutational analysis of a higher plant antenna protein provides identification of chromophores bound into multiple sites. | The chromophore-binding properties of the higher plant light-harvesting protein CP29 have been studied by using site-directed mutagenesis of pigment-binding residues. Overexpression of the apoproteins in bacteria was followed by reconstitution in vitro with purified pigments, thus obtaining a family of mutant CP29 prot... |
10471033 | Different adhesion properties of highly and poorly metastatic HT-29 colon carcinoma cells with extracellular matrix components: role of integrin expression and cytoskeletal components. | Integrin-mediated tumour cell adhesion to extracellular matrix (ECM) components is an important step in the development of metastatic lesions. Thus, integrin expression and integrin-mediated adhesion of colon carcinoma cells to various ECM components was examined. Poorly (HT-29P) and highly (HT-29LMM) liver-metastatic ... |
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