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29710997 | Synthesis and Characterization of a Unimolecular Capsule. | There is more than one way to assemble the two halves of a tethered, urea-substituted calix[4]arene dimer (shown schematically): formation of unimolecular capsules (far left), dimers, or oligomers. By combination of NMR spectroscopy and electrospray mass spectrometry, a hexamethylene spacer was shown to be exactly righ... |
29710989 | Total Synthesis of (-)-Bafilomycin A<sub>1</sub> : Application of Diastereoselective Crotylboration and Methyl Ketone Aldol Reactions. | A careful orchestration of protecting groups is an essential requirement for the total synthesis of the macrolide antibiotic bafilomycin A<sub>1</sub> (1). Key steps were the Suzuki cross-coupling reaction of two advanced, suitably protected intermediates prior to closure of the macrocycle, as well as a highly stereose... |
29710987 | Photoswitchable Hydrogen-Bonding in Self-Organized Cylindrical Peptide Systems. | The new photochromic supramolecular system 1 is based on the E→Z isomerization of an azobenzene substituted with cyclic peptides with alternating D- and L-α-amino acids. This system allows reversible switching between inter- and intramolecularly assembled cylindrical β-sheet structures in solution as well as in thin fi... |
29710986 | Triple Helicate-Tetrahedral Cluster Interconversion Controlled by Host-Guest Interactions. | A unique ligand design allows the formation of both an M<sub>2</sub> L<sub>3</sub> triple helicate and an M<sub>4</sub> L<sub>6</sub> tetrahedron (M=Ti, Ga; L=ligand based on 2,6-diaminoanthracene). Although the tetrahedron is entropically disfavored, a strong host-guest interaction with Me<sub>4</sub> N<sup>+</sup> is... |
29710985 | Asymmetric Phase-Transfer Catalysis. | Both in the laboratory and industrially, phase-transfer catalysis offers the potential to induce asymmetry into reactions with anionic intermediates. Equation (a) provides an example (conditions: a) 10 mol % phase-transfer catalyst, BnBr, CsOH⋅H<sub>2</sub> O, PhMe, 15-24 h, -78°C). |
29710976 | Self-Assembly of Quinodimethanes through Covalent Bonds: A Novel Principle for the Synthesis of Functional Macrocycles. | A multiplication of functional units was accomplished in a simple fashion by the tetramerization of a quinodimethane. This principle is demonstrated by the convergent construction of a macrocyclic molecule with 16 ferrocenes and a macrocyclic molecule with 16 dendritic units at the periphery of the molecule (see scheme... |
27518049 | Electrospray ionization mass spectrometric analysis of self-assembled 1,1'-ferrocenedicarboxylic acid. | Self-assembly of 1,1'-ferrocenedicarboxylic acid in solution was detected by electrospray mass spectrometry (ESI-MS). The ESI mass spectra showed the acid was self-assembled as a cyclic tetramer in methanol and acetonitrile, and the tetramer was found to complex more strongly with the sodium ion than with any other alk... |
27518044 | Fragmentation of molecules sliding along surfaces in the speed range above thermal and below Bohr velocity. | A theoretical model and experimental time-of-flight mass spectrometric data for the fragmentation of molecules grazing along surfaces at velocities v = 10(5)-10(6) cm/s are presented. The effect of enhanced surface-induced dissociation at grazing incidence (GI-SID) is shown for hexadecylpyridine ions. The velocity depe... |
23345701 | Molecular dynamics investigation of bond ordering of unsaturated lipids in monolayers. | Molecular dynamics simulations of three model lipid monolayers of 2,3-diacyl-D-glycerolipids, that contained stearoyl (18:0) in the position 3 and oleoyl (18:ω9cis), linoleoyl (18:2ω6cis), or linolenoyl (18:3ω3cis) in the position 2, have been carried out. The simulation systems consisted of 24 lipid molecules arranged... |
21662750 | Artificial receptor-facilitated solid-phase microextraction of barbiturates. | A receptor for barbiturates, N,N'-Bis-[6-(2-ethylhexanoylamino)-pyridin-2-yl]-isophthalamide, was designed to dissolve in plasticizers of poly(vinyl chloride) (PVC). Microextractions using receptor-doped films of PVC were carried out as a function of receptor concentration. The effect of the concentration of the recept... |
18505540 | Interaction of Fragrance Materials With 2-Hydroxypropyl-beta-Cyclodextrin by Static and Dynamic Head-space Methods. | The stability constants for the inclusion of fragrance materials with 2-hydroxypropyl-beta-cyclodextrin (2HP-beta-C yD) in aqueous solution have been determined by the static head-space method. The 1:1 stability constants obtained by this method were in reasonable agreement with the corresponding values in the literatu... |
10927382 | Crystal structures of | The crystal structures of [18]aneN(6)H(2)K[Co(CN)(6)].4H(2)O [potassium dihydrogen hexacyanocobaltate-1,4,7,10,13,16-hexaazacyclooctadecane-water (1/1/4)], [16]aneN(4)H(2)K[Co(CN)(6)] [potassium dihydrogen hexacyanocobaltate-1,5,9,13-tetraazacyclohexadecane (1/1)] and [12]aneN(4)H(3)[Co(CN)(6)].2H(2)O [trihydrogen hexa... |
10407282 | Formation of macrocyclic oligoferrocenes: a matrix-assisted laser desorption/ionization mass spectrometric study. | Oligomeric ferrocenes were investigated simultaneously by matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOFMS). The oligomers were obtained by the reaction of tetrahydro-4,4,8,8-tetramethyl-4,8-disila-s-indacene-3a,7a-diyldilithium (Li(2)L) with FeCl(2).1.5 THF (THF = tetrahydrofur... |
10393259 | Xanthophyll pigments in light-harvesting complex II in monomolecular layers: localisation, energy transfer and orientation | Monomolecular layers of the largest light-harvesting pigment-protein complex of Photosystem II (LHCII) were formed at the argon-water interface. The molecular area of the LHCII monomer in monomolecular layers determined from the isotherms of compression is found to be close to 14 nm2, which corresponds well to the mole... |
10359753 | Self-assembly of chlorophenols in water. | In saturated solutions of some di- and trichlorophenols, structures with complex morphologies, consisting of thin, transparent sheets often coiling into helices and ultimately twisting into filaments, were observed under the optical microscope. Freeze-fracture electron microscopy, x-ray diffraction, phase diagrams, and... |
11674554 | Ring-Closing Metathesis in the Synthesis of Large and Medium-Sized Oxacycles. Application to the Synthesis of Polyoxygenated Macrocycles. | Ring-closing olefin metathesis (RCM) catalyzed by Grubbs's ruthenium benzylidene complex 1 is applied to the synthesis of unsaturated rings ranging in size from seven to thirteen members in trans-fused polyether systems. Reaction occurs with great efficiency in the cyclization of oxepene and oxocene rings, but as ring ... |
11671048 | Unusual Ligand Isomerization Dictated by Coordination Requirements of the Metal Ion: A Double-Bond Shift in Cu(II)-Assisted Template Condensation between Diacetylpyridine and a Tripodal Tetramine. | This paper reports a new effect in template-directed Schiff base condensation, a "fine-tuning" of the macrocyclic structure in accordance with the precise coordination requirements of the metal ion. The nature of the metal template determines the outcome of Schiff base condensation between a difunctional carbonyl compo... |
11671046 | Structure-Reactivity Studies in Copper(II)-Catalyzed Phosphodiester Hydrolysis. | We have investigated the ability of a series of three related copper complexes Cu([9-11]aneN(3))X(2) to hydrolyze the activated phosphodiesters bis(4-nitrophenyl) phosphate (BNPP) and ethyl 4-nitrophenyl phosphate (ENPP). The compound Cu([10]aneN(3))Br(2) crystallizes in the monoclinic space group C2/c, a = 20.693(4) Å... |
11671037 | Synthesis, X-ray Structure, and Solution NMR Studies of Ln(III) Complexes with a Macrocyclic Asymmetric Compartmental Schiff Base. Preference of the Ln(III) Ions for a Crown-Like Coordination Site. | The compartmental ligand H(2)L(A), containing an N(3)O(2) Schiff base and an O(2)O(3) crown like coordination site, has been prepared by reaction of 3,3'-(3-oxapentane-1,5-diyldioxy)bis(2-hydroxybenzaldehyde) with 1,5-diamino-3-azamethylpentane. The formation of a [1+1] macrocycle was inferred by IR, NMR, and mass spec... |
11671036 | Ultraviolet Photochemistry of Co(III)L(H(2)O)SO(3)(+) [L = Me(6)[14]dieneN(4), [14]aneN(4)] Complexes. Quandaries about the Linkage Isomerization to O-Bonded Sulfite and the Photogeneration of Cobalt(I) in Sequential Biphotonic Photolysis. | Two new macrocyclic complexes with S-bonded sulfite, Co(Me(6)[14]diene N(4))(H(2)O)SO(3)(+) and Co([14]ane N(4))(H(2)O)SO(3)(+), were prepared. The type of the SO(3)(2)(-) linkage in [Co(Me(6)[14]dieneN(4))(H(2)O)SO(3)]ClO(4) was established by means of the X-ray structure (crystal system, orthorhombic; space group, P2... |
12779825 | The guest-induced oscillation of a monolayer composed of polypeptide containing beta-cyclodextrin at the terminal. | We prepared a rod-like amphiphile with a molecular recognition end group, alpha-helical and hydrophobic poly(gamma-methyl L-glutamate) (PMG) containing hydrophilic beta-cyclodextrin (CyD) as an active end group (PMG-CyD), and formed its monolayer at the n-hexane/water interface. The interfacial pressure (pi)-area (A) i... |
14634282 | Adenosine-induced cell death: evidence for receptor-mediated signalling. | Adenosine modulates the proliferation, survival and apoptosis of many different cell types, ranging from epithelial, endothelial and smooth muscle cells, to cells of the immune and neural lineages. In this review, we critically discuss the available in vitro and in vivo data which support a role for adenosine in both d... |
12575070 | [A fluorimetric study of the interactions of hydrochloridum berberini with vinylpyrrolidone and beta-cyclodextrin]. | The interactions of hydrochloridum berberini with 1-vinyl-2-pyrrolidone and beta-cyclodextrin in aqueous solution were studied by spectrofluorimetric method. The spectral changes were quantitatively investigated. Results showed that the complexation with beta-cyclodextrin resulted in an enhancement of the fluorescence ... |
10704021 | Separation of morphine and its oxidation products by capillary zone electrophoresis. | Separation of morphine and its oxidation products (10-S-hydroxymorphine, pseudomorphine and morphine N-oxide) by capillary zone electrophoresis in Tris-borate buffer in the presence of cyclodextrins was studied. Pyridoxine was used as an internal standard. |
10636700 | Analytical study of penicillamine in pharmaceuticals by capillary zone electrophoresis. | The ability of capillary zone electrophoresis in the development of analytical methods devoted to the quality control of the thiol drug penicillamine is shown. Using 50 mM phosphate running buffer (pH 2.5), good quantitations of underivatized penicillamine and its disulfide were achieved; detection at 200 nm allowed ch... |
10559881 | Dominant-negative caveolin inhibits H-Ras function by disrupting cholesterol-rich plasma membrane domains. | The plasma membrane pits known as caveolae have been implicated both in cholesterol homeostasis and in signal transduction. CavDGV and CavKSY, two dominant-negative amino-terminal truncation mutants of caveolin, the major structural protein of caveolae, significantly inhibited caveola-mediated SV40 infection, and were ... |
10503237 | Reconstitution of fibroblast growth factor receptor interactions in the yeast two hybrid system. | Fibroblast growth factors (FGF) activate their receptors through the formation of trimolecular complexes, composed of a ligand, a receptor, and a heparan sulfate oligosaccharide, all of which are members of particularly large families capable of multiple interactions in a combinatorial fashion. Understanding this large... |
10484291 | Immunoaffinity isolation of native membrane glucocorticoid receptor from S-49++ lymphoma cells: biochemical characterization and interaction with Hsp 70 and Hsp 90. | The membrane glucocorticoid receptor (mGR), previously correlated with glucocorticoid-induced lymphocytolytic competency, was purified under nondenaturing conditions from mGR-enriched mouse S-49 T lymphoma cells. Proteins were immunoaffinity batch adsorbed to BUGR-2 monoclonal antibody-coupled protein A Sepharose 4B be... |
10474256 | Uptake and intracellular distribution of oligonucleotides vectorized by a PAMAM dendrimer. | We studied the uptake and intracellular distribution of an FITC labelled phosphodiester oligodeoxynucleotide (ODN) vectorized by a dendrimeric structure in cell culture. |
10437670 | Simultaneous determination of the urinary metabolites of toluene, xylene and styrene using high-performance capillary electrophoresis. Comparison with high-performance liquid chromatography. | A simple and rapid method using high-performance capillary electrophoresis (HPCE) for the simultaneous determination of the urinary metabolites of toluene, xylene and styrene, plus creatinine and uric acid in human urine specimens and standard solutions is described. The compounds were well separated from each other on... |
10437666 | Determination of the D- and L-enantiomers of modafinil in human plasma utilizing liquid-liquid extraction and high-performance liquid chromatography. | Modafinil, DL-2-[(diphenylmethyl)sulfinyl]acetamide (Provigil), which is chiral at its sulfur atom, is a novel wake-promoting agent currently being developed as the racemate in the United States by Cephalon, Inc. In order to characterize the pharmacokinetic properties of each enantiomer, a stereospecific high-performan... |
10434300 | Properties of polyglutamine expansion in vitro and in a cellular model for Huntington's disease. | Eight neurodegenerative diseases have been shown to be caused by the expansion of a polyglutamine stretch in specific target proteins that lead to a gain in toxic property. Most of these diseases have some features in common. A pathological threshold of 35-40 glutamine residues is observed in five of the diseases. The ... |
10434297 | Aggregation of truncated GST-HD exon 1 fusion proteins containing normal range and expanded glutamine repeats. | We have shown previously by electron microscopy that the purified glutathione S-transferase (GST)-Huntington's disease (HD) exon 1 fusion protein with 51 glutamine residues (GST-HD51) is an oligomer, and that site-specific proteolytic cleavage of this fusion protein results in the formation of insoluble more highly ord... |
10431867 | The European experience of Novacor left ventricular assist (LVAS) therapy as a bridge to transplant: a retrospective multi-centre study. | <h4>Objective</h4>Artificial heart devices have suffered from a negative press based on the early Jarvik experience of the 1980s. This is in stark contrast to realities of current left ventricular assist (LVAS) therapy. The Novacor N100 PC wearable left ventricular assist system (LVAS) was introduced in Europe in late ... |
10427742 | Refinement of the structure of protein-RNA complexes by residual dipolar coupling analysis. | The main limitation in NMR-determined structures of nucleic acids and their complexes with proteins derives from the elongated, non-globular nature of physiologically important DNA and RNA molecules. Since it is generally not possible to obtain long-range distance constraints between distinct regions of the structure, ... |
10428385 | Self-aggregates of a synthetic cadmium chlorin in solid film as a photosynthetic antenna model. | Self-aggregates of a synthetic cadmium chlorin possessing 3(1)-hydroxyl and 13-carbonyl groups were prepared in dried thin film. The solid film was characterized by visible and infrared absorption spectroscopies at both transmission and reflection modes. The spectra given by the two different modes were essentially the... |
10428382 | Silver and thallium(I) complexation with dibenzo-16-crown-4. | Dibenzo-16-crown-4 (1) indicates high silver and thallium(I) ion selectivity over sodium, potassium, and rubidium ion evaluated from the solvent extraction of metal picrates, while its cation-binding ability is lower than those of dibenzo-18-crown-6 (2) and dibenzo-22-crown-6 (3). Taking account of the highest thallium... |
10424480 | Enantioseparation of tropa alkaloids by means of anionic cyclodextrin-modified capillary electrophoresis. | Anionic cyclodextrins (CDs), i.e., sulfated CD, sulfobutylether beta-CD (SBE-beta-CD) and heptakis(2,3-di-O-acetyl-6-sulfato)-beta-CD (HDAS-beta-CD), were used to separate the isomers of atropine, homatropine, ipratropium, scopolamine and butylscopolamine. Variations in the pH value and the concentration of the various... |
10424479 | Separation of resin acids using cyclodextrin-modified capillary electrophoresis. | A cyclodextrin-modified capillary electrophoretic method has been developed for the analysis of eleven common resin acids using a pH 4.5, 20 mM sodium acetate buffer containing 10% acetonitrile, 20 mM methyl-beta-cyclodextrin (MECD) and 30 mM sulfobutylether-beta-cyclodextrin (SBCD) as buffer modifiers. At pH below the... |
10424478 | Enantiomeric separation of amino acids derivatized with fluoresceine isothiocyanate isomer I by micellar electrokinetic chromatography using beta- and gamma-cyclodextrins as chiral selectors. | Enantiomeric separation of 21 amino acids derivatized with fluoresceine isothiocyanate isomer I (FITC) has been studied by micellar electrokinetic chromatography using beta- and gamma-cyclodextrin (CD) as chiral selectors. Chiral resolution of 21 FITC derivatives of amino acids was achieved with both beta- and gamma-CD... |
10422220 | Extremophiles as a source of novel enzymes for industrial application. | Extremophilic microorganisms are adapted to survive in ecological niches such as at high temperatures, extremes of pH, high salt concentrations and high pressure. These microorganisms produce unique biocatalysts that function under extreme conditions comparable to those prevailing in various industrial processes. Some ... |
10420615 | Trace analysis of haloperidol and its chiral metabolite in plasma by capillary electrophoresis. | Capillary zone electrophoresis was developed for the simultaneous determination of haloperidol (HP) and its chiral metabolites [(+)- and (-)- reduced haloperidol, (+)- and (-)-RHP] in human plasma. The method involved the presence of an internal standard and liquid-liquid extraction from plasma. After concentration, th... |
10420614 | Simultaneous stereoselective analysis by capillary electrophoresis of tramadol enantiomers and their main phase I metabolites in urine. | Capillary zone electrophoresis was successfully applied to the enantiomeric resolution of racemic tramadol and its six phase I metabolites using carboxymethylated beta-cyclodextrin (CMB) added to the background electrolyte (BGE). Baseline resolution of tramadol and its metabolites was obtained in less than 30 min using... |
10420600 | High-performance liquid chromatographic separation of novel atropic alpha,alpha-disubstituted-beta-amino acids, either on different beta-cyclodextrin-bonded phases or as their 1-fluoro-2,4-dinitrophenyl-5-L-alanine amide derivatives. | The high-performance liquid chromatographic enantioresolution of free and N- and/or C-protected derivatives of (R,S)-2',1':1,2;1",2":3,4-dinaphthcyclohepta-1,3-diene-6-aminometh yl-6- carboxylic acid (beta 2-Bin) by direct and indirect methods is reported. The direct separation was carried out on native and different d... |
10416675 | Polymers of malic acid and 3-alkylmalic acid as synthetic PHAs in the design of biocompatible hydrolyzable devices. | Poly(beta-malic acid) and poly(beta-3-alkylmalic acid) derivatives, as synthetic polyhydroxyalkanoates (PHAs), present several advantages as macromolecular materials for temporary biomedical applications. Indeed, such polymers, which can be synthesized through different chemical and biological routes, have cleavable es... |
10412374 | Enteropathogenic Escherichia coli: a pathogen that inserts its own receptor into host cells. | Enteropathogenic Escherichia coli (EPEC) is a major cause of infant diarrhea, killing hundreds of thousands of children per year worldwide. Intimate attachment to the host cell leading to the formation of actin-rich pedestals beneath the adhering bacteria is an essential feature of EPEC pathogenesis. EPEC attaches to h... |
10410931 | Direct determination of methamphetamine enantiomers in urine by liquid chromatography with a strong cation-exchange precolumn and phenyl-beta-cyclodextrin-bonded semi-microcolumn. | Methamphetamine enantiomers in drug abusers' urine were clearly separated by semi-microcolumn liquid chromatography using a column-switching system. The system consists of two separation processes: firstly, a strong cation-exchange precolumn removes neutral and anionic substances in urine, and then methamphetamine enan... |
10410925 | Achiral and chiral determination of ciprofibrate and its glucuronide in human urine by capillary electrophoresis. | A method for achiral separation of the racemic hypolipidaemic agent ciprofibrate and its main metabolite ciprofibrate glucuronide by capillary electrophoresis (CE) was developed. The glucuronide was isolated from urine by chromatographic procedures and characterized by alkaline as well as enzymatic hydrolysis and mass ... |
10408090 | Chiral recognition between host and guest: a binaphthyl-18-crown-6 host with D-phenylglycinium methyl ester perchlorate guest. A difficult structure solved with CRUNCH. | The complex between (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,- 10,13,16]hexaoxa[2,5,8,11,14,17,19]cycloicosaheptene {Chemical Abstracts name: (R)-4,5,7,8,10,11,13,14,16,17-decahydro-2,19- diphenyldinaphtho[2,1-q:1',2'-s][1,4,7,-10,13,16]hexaoxacycloic osin} and D-2-phenylglyc... |
10408086 | (C2H10N2)[Co(H2O)6](HPO4)2: a supramolecular three-dimensional hydrogen-bonding network. | The title compound, ethylenediammonium hexaaquacobalt bis(hydrogenphosphate), consists of [Co(H2O)6]2+ and [enH2]2+ cations (en is ethylenediamine), and [HPO4]2- anions interconnected by an extensive intermolecular three-dimensional hydrogen-bonding network. The [enH2]2+ cations play an important role in the templating... |
10405165 | Design of generic biosensors based on green fluorescent proteins with allosteric sites by directed evolution. | Protein-engineering techniques have been adapted for the molecular design of biosensors that combine a molecular-recognition site with a signal-transduction function. The optical signal-transduction mechanism of green fluorescent protein (GFP) is most attractive, but hard to combine with a ligand-binding site. Here we ... |
10401565 | Serotonin reuptake inhibitor, fluoxetine, dilates isolated skeletal muscle arterioles. Possible role of altered Ca2+ sensitivity. | 1. Inhibitors of serotonin reuptake in the central nervous system, such as fluoxetine, may also affect the function of vascular tissues. Thus, we investigated the effect of fluoxetine on the vasomotor responses of isolated, pressurized arterioles of rat gracilis muscle (98 +/- 4 microns in diameter at 80 mmHg perfusion... |
10401559 | Protective effects of a superoxide dismutase mimetic and peroxynitrite decomposition catalysts in endotoxin-induced intestinal damage. | 1. The relative contributions of superoxide anion (O2-) and peroxynitrite (PN) were evaluated in the pathogenesis of intestinal microvascular damage caused by the intravenous injection of E. coli lipopolysaccharide (LPS) in rats. The superoxide dismutase mimetic (SODm) SC-55858 and the active peroxynitrite decompositio... |
10401553 | Comparative effects of cyclo-oxygenase and nitric oxide synthase inhibition on the development and reversal of spinal opioid tolerance. | 1. This study examined the effects of the COX inhibitors, ketorolac and ibuprofen, and the NOS inhibitor L-NAME for their potential to both inhibit the development and reverse tolerance to the antinociceptive action of morphine. 2. Repeated administration of intrathecal morphine (15 micrograms), once daily, resulted in... |
10399836 | Topology effect for DNA structure of cisplatin: topological transformation of cisplatin-closed circular DNA adducts by DNA topoisomerase I. | The reaction of cis-Pt(NH3)2Cl2(cis-DDP)-closed circular DNA adducts with DNA topoisomerse I(topo I) were studied by electron microscopy. We identified unique topoisomers such as a singly-linked catenane (2(1)2), trefoil (3(1), and dimetric catenane (2(1)2), etc., by analysis with electron micrographs. These unique rec... |
10399341 | Interaction of some steroid drugs with beta-cyclodextrin polymer. | The interaction of 15 steroidal drugs with a water-soluble beta-cyclodextrin polymer was studied by reversed-phase thin-layer chromatography in the absence and in the presence of 0.1 M sodium chloride. The relative strength of interaction was calculated and the relationship between the hydrophobicity parameters of the ... |
10397974 | Hydrophilic acrylic biomaterials derived from vitamin E with antioxidant properties. | Hydrogels based on polymeric derivatives of vitamin E for biomedical purposes have been prepared by copolymerization reaction of the alpha-tocopheryl methacrylate (V) with 2-hydroxyethyl methacrylate (H) in a range of composition between 5-20 wt % of V. The swelling behavior of the hydrogels in water, alkaline, and aci... |
10395563 | Histone H1: location and role. | Recent experiments have shown directly that, in bulk chromatin, the globular domain of histone H1 is positioned close to the dyad axis and is asymmetrically disposed, consistent with a polar arrangement of H1 molecules along the nucleosome filament. In addition to a structural role, H1 may also have gene-specific effec... |
10397605 | Cyclodextrins as diethylstilbestrol carrier system: characterization of diethylstilbestrol-cyclodextrins complexes. | <h4>Purpose</h4>The in vitro formation of DES-cyclodextrins inclusion complexes was characterized using lipoxygenase as enzymatic system.<h4>Methods</h4>DES-cyclodextrins complexes were obtained in aqueous solution.<h4>Results</h4>The addition of cyclodextrins to the reaction medium had an inhibitory effect on DES oxid... |
10394813 | Present and future options in continuous renal replacement therapies of sepsis and MOF. | Conventional continuous extracorporeal treatments such as hemofiltration and hemodiafiltration have not achieved significant reduction in cytokine plasma levels, in spite of their increasing popularity mainly related to the unnecessary fluid restriction thereby rendering adequate caloric intake possible (Actualités Nep... |
10388846 | A general method for relieving substrate inhibition in lactate dehydrogenases. | The mutation S163L in human heart lactate dehydrogenase removes substrate inhibition while only modestly reducing the turnover rate for pyruvate. Since this is the third enzyme to show this behaviour, we suggest that the S163L mutation is a general method for the removal of substrate inhibition in L-LDH enzymes. Engine... |
10387022 | Role of the distal phenylalanine 54 on the structure, stability, and ligand binding of Coprinus cinereus peroxidase. | Resonance Raman and electronic absorption spectra obtained at various pH values for the Fe3+ form of distal F54 mutants of Coprinus cinereus peroxidase are reported, together with the Fe2+ form and fluoride and imidazole adducts at pH 6.0, 5.0, and 10.5, respectively. The distal phenylalanine residue has been replaced ... |
10385528 | Direct involvement of ezrin/radixin/moesin (ERM)-binding membrane proteins in the organization of microvilli in collaboration with activated ERM proteins. | Ezrin/radixin/moesin (ERM) proteins have been thought to play a central role in the organization of cortical actin-based cytoskeletons including microvillar formation through cross-linking actin filaments and integral membrane proteins such as CD43, CD44, and ICAM-2. To examine the functions of these ERM-binding membra... |
10385520 | Chromosomal influence on meiotic spindle assembly: abnormal meiosis I in female Mlh1 mutant mice. | In mouse oocytes, the first meiotic spindle is formed through the action of multiple microtubule organizing centers rather than a pair of centrosomes. Although the chromosomes are thought to play a major role in organizing the meiotic spindle, it remains unclear how a stable bipolar spindle is established. We have stud... |
10385516 | Large-scale chromatin unfolding and remodeling induced by VP16 acidic activation domain. | Analysis of the relationship between transcriptional activators and chromatin organization has focused largely on lower levels of chromatin structure. Here we describe striking remodeling of large-scale chromatin structure induced by a strong transcriptional activator. A VP16-lac repressor fusion protein targeted the V... |
10387084 | X-ray structure of Novamyl, the five-domain "maltogenic" alpha-amylase from Bacillus stearothermophilus: maltose and acarbose complexes at 1.7A resolution. | The three-dimensional structure of the Bacillus stearothermophilus "maltogenic" alpha-amylase, Novamyl, has been determined by X-ray crystallography at a resolution of 1.7 A. Unlike conventional alpha-amylases from glycoside hydrolase family 13, Novamyl exhibits the five-domain structure more usually associated with cy... |
10387070 | Water-soluble beta-sheet models which self-assemble into fibrillar structures. | Self-assembly of beta-sheet domains resulting in the formation of pathogenic, fibrillar protein aggregates (amyloids) is a characteristic feature of various medical disorders. These include neurodegenerative diseases, such as Alzheimer's, Huntington's, and Creutzfeldt-Jacob's. A significant problem in studying such agg... |
10387041 | Molecular recognition of macrocyclic peptidomimetic inhibitors by HIV-1 protease. | High-resolution crystal structures are described for seven macrocycles complexed with HIV-1 protease (HIVPR). The macrocycles possess two amides and an aromatic group within 15-17 membered rings designed to replace N- or C-terminal tripeptides from peptidic inhibitors of HIVPR. Appended to each macrocycle is a transiti... |
10387040 | Crystal structures of thrombin complexed to a novel series of synthetic inhibitors containing a 5,5-trans-lactone template. | The binding modes of four active site-directed, acylating inhibitors of human alpha-thrombin have been determined using X-ray crystallography. These inhibitors (GR157368, GR166081, GR167088, and GR179849) are representatives of a series utilizing a novel 5, 5-trans-lactone template to specifically acylate Ser195 of thr... |
10387039 | Electrostatic and aromatic microdomains within the binding-site crevice of the D2 receptor: contributions of the second membrane-spanning segment. | The binding-site of the dopamine D2 receptor, like that of other homologous G protein-coupled receptors, is contained within a water-accessible crevice formed among its seven membrane-spanning segments. Using the substituted cysteine accessibility method (SCAM), we previously mapped the residues in the third, fifth, si... |
10386882 | Autonomous folding of a peptide corresponding to the N-terminal beta-hairpin from ubiquitin. | The N-terminal 17 residues of ubiquitin have been shown by 1H NMR to fold autonomously into a beta-hairpin structure in aqueous solution. This structure has a specific, native-like register, though side-chain contacts differ in detail from those observed in the intact protein. An autonomously folding hairpin has previo... |
10381357 | Activation of caspase-3 apoptotic pathways in skeletal muscle fibers in laminin alpha2-deficient mice. | dy/dy mice, which carry an unidentified mutation in the Lama2 gene, show dystrophic pathologies similar to those of human congenital muscular dystrophy. Laminin alpha2 deficiency induces apoptosis with DNA fragmentation. Caspases, which are involved in various types of cell death, are sequentially activated through a p... |
10377443 | Constitutive cell surface association between CD4 and CCR5. | HIV-1 entry into cells involves formation of a complex between gp120 of the viral envelope glycoprotein (Env), a receptor (CD4), and a coreceptor. For most strains of HIV, this coreceptor is CCR5. Here, we provide evidence that CD4 is specifically associated with CCR5 in the absence of gp120 or any other receptor-speci... |
10377398 | cDNA cloning of cholesterol 24-hydroxylase, a mediator of cholesterol homeostasis in the brain. | The turnover of cholesterol in the brain is thought to occur via conversion of excess cholesterol into 24S-hydroxycholesterol, an oxysterol that is readily secreted from the central nervous system into the plasma. To gain molecular insight into this pathway of cholesterol metabolism, we used expression cloning to isola... |
10377396 | Purification of the yeast U4/U6.U5 small nuclear ribonucleoprotein particle and identification of its proteins. | The yeast U4/U6.U5 pre-mRNA splicing small nuclear ribonucleoprotein (snRNP) is a 25S small nuclear ribonucleoprotein particle similar in size, composition, and morphology to its counterpart in human cells. The yeast U4/U6.U5 snRNP complex has been purified to near homogeneity by affinity chromatography and preparative... |
10377383 | mRNA cap recognition: dominant role of enhanced stacking interactions between methylated bases and protein aromatic side chains. | We have determined, by high resolution x-ray analysis, 10 structures comprising the mRNA cap-specific methyltransferase VP39 or specific mutants thereof in the presence of methylated nucleobase analogs (N1-methyladenine, N3-methyladenine, N1-methylcytosine, N3-methylcytosine) and their unmethylated counterparts, or nuc... |
10377232 | 2,4-Diphenyl furan diamidines as novel anti-Pneumocystis carinii pneumonia agents. | Dicationic 2,4-bis(4-amidinophenyl)furans 5-10 and 2, 4-bis(4-amidinophenyl)-3,5-dimethylfurans 14 and 15 have been synthesized. Thermal melting studies revealed high binding affinity of the compounds to poly(dA-dT) and to the duplex oligomer d(CGCGAATTCGCG)2. All of the new compounds were effective against Pneumocysti... |
10379705 | Acquired skin disease of hemidesmosomes. | The hemidesmosome is a membrane-associated supramolecular dermal epidermal complex linking the cytoskeleton of the basal keratinocyte to structures within the papillary dermis. Different components of this complex have been identified as autoantigens in autoimmune bullous skin diseases. Some of the autoantigens have be... |
10360956 | Rhodocetin, a novel platelet aggregation inhibitor from the venom of Calloselasma rhodostoma (Malayan pit viper): synergistic and noncovalent interaction between its subunits. | A novel platelet aggregation inhibitor, rhodocetin, was purified from the crude venom of Calloselasma rhodostoma. It inhibited collagen-induced platelet aggregation in a dose-dependent manner, with an IC50 of 41 nM. Rhodocetin has a heterodimeric structure with alpha and beta subunits, which could be separated on a non... |
10373373 | Crystal structure of a ternary complex between human chorionic gonadotropin (hCG) and two Fv fragments specific for the alpha and beta-subunits. | Human chorionic gonadotropin (hCG), is a placental hormone which exerts its major effect by stimulating progesterone production, crucially sustaining the early weeks of pregnancy. Detection of hCG with specific monoclonal antibodies (mAbs) has become the chosen means for pregnancy diagnosis. We have used antibody Fv fr... |
10373363 | Topological selectivity of a hybrid site-specific recombination system with elements from Tn3 res/resolvase and bacteriophage P1 loxP/Cre. | In order to investigate the functions of the parts of the Tn 3 recombination site res, we created hybrid recombination sites by placing the loxP site for Cre recombinase adjacent to the "accessory" resolvase-binding sites II and III of res. The efficiency and product topology of in vitro recombination by Cre between tw... |
10376881 | Efficient reconstitution of functional Escherichia coli 30S ribosomal subunits from a complete set of recombinant small subunit ribosomal proteins. | Previous studies have shown that the 30S ribosomal subunit of Escherichia coli can be reconstituted in vitro from individually purified ribosomal proteins and 16S ribosomal RNA, which were isolated from natural 30S subunits. We have developed a 30S subunit reconstitution system that uses only recombinant ribosomal prot... |
10376878 | Mutations in the MOF2/SUI1 gene affect both translation and nonsense-mediated mRNA decay. | Recent studies have demonstrated that cells have evolved elaborate mechanisms to rid themselves of aberrant proteins and transcripts. The nonsense-mediated mRNA decay pathway (NMD) is an example of a pathway that eliminates aberrant mRNAs. In yeast, a transcript is recognized as aberrant and is rapidly degraded if a sp... |
10376873 | A potential mechanism for selective control of cap-independent translation by a viral RNA sequence in cis and in trans. | Highly efficient cap-independent translation initiation at the 5'-proximal AUG is facilitated by the 3' translation enhancer sequence (3'TE) located near the 3' end of barley yellow dwarf virus (BYDV) genomic RNA. The role of the 3'TE in regulating viral translation was examined. The 3'TE is required for translation an... |
10376596 | Tuning bilayer twist using chiral counterions. | From seashells to DNA, chirality is expressed at every level of biological structures. In self-assembled structures it may emerge cooperatively from chirality at the molecular scale. Amphiphilic molecules, for example, can form a variety of aggregates and mesophases that express the chirality of their constituent molec... |
10369775 | Conformational dynamics and molecular recognition: backbone dynamics of the estrogen receptor DNA-binding domain. | We examined the internal mobility of the estrogen receptor DNA-binding domain (ER DBD) using NMR15N relaxation measurements and compared it to that of the glucocorticoid receptor DNA-binding domain (GR DBD). The studied protein fragments consist of residues Arg183-His267 of the human ER and residues Lys438-Gln520 of th... |
10369768 | Topology of Xer recombination on catenanes produced by lambda integrase. | Xer site-specific recombination at the psi site from plasmid pSC101 displays topological selectivity, such that recombination normally occurs only between directly repeated sites on the same circular DNA molecule. This intramolecular selectivity is important for the biological role of psi, and is imposed by accessory p... |
10368423 | Sweet taste responses of mouse chorda tympani neurons: existence of gurmarin-sensitive and -insensitive receptor components. | Inhibitory effects of gurmarin (gur) on responses to sucrose and other sweeteners of single fibers of the chorda tympani nerve in C57BL mice were examined. Of 30 single fibers that strongly responded to 0. 5 M sucrose but were not or to lesser extent responsive to 0.1 M NaCl, 0.01 M HCl, and 0.02 M quinine HCl (sucrose... |
10369683 | Promoter upstream bent DNA activates the transcription of the Clostridium perfringens phospholipase C gene in a low temperature-dependent manner. | The phospholipase C gene (plc) of Clostridium perfringens possesses three phased A-tracts forming bent DNA upstream of the promoter. An in vitro transcription assay involving C.perfringens RNA polymerase (RNAP) showed that the phased A-tracts have a stimulatory effect on the plc promoter, and that the effect is proport... |
10366631 | Positionally selective growth of embryonic spinal cord neurites on muscle membranes. | Motor neurons from distinct positions along the rostrocaudal axis generally innervate muscles or muscle fibers from corresponding axial levels. These topographic maps of connectivity are partially restored after denervation or transplantation under conditions in which factors of timing and proximity are eliminated. It ... |
10366863 | Bacterial S-layers. | S-layers are produced by the self assembly of proteinaceous subunits on the surfaces of prokaryotes, so that planar, monomolecular-thick crystalline lattices are formed. Some archaeal and eubacterial S-layer proteins are glycosylated. These lattices typically have center-to-center spacings of less than 25 nm, which mak... |
10366728 | Bacillus thuringiensis insecticidal Cry1Aa toxin binds to a highly conserved region of aminopeptidase N in the host insect leading to its evolutionary success. | Bacillus thuringiensis insecticidal protein, Cry1Aa toxin, binds to a specific receptor in insect midguts and has insecticidal activity. Therefore, the structure of the receptor molecule is probably a key factor in determining the binding affinity of the toxin and insect susceptibility. The cDNA fragment (PX frg1) enco... |
10361154 | Distribution of a lipidic 2.5 nm diameter dendrimer carrier after oral administration. | The biodistribution of a lipidic peptide dendrimer has been studied after oral administration to female Sprague-Dawley rats (180 g, 9 weeks old). Uptake by gut epithelial tissue of the radiolabelled dendrimer molecule (mol. wt. 6300; diameter 2.5 nm; log P=1.24) was studied in rats after a single oral dose by gavage (1... |
10361088 | Oligonucleotide aptamers that recognize small molecules. | Nucleic acid receptors ('aptamers'), which recognize a large variety of organic molecules of low molecular weight, have been isolated from combinatorial nucleic acid libraries by in vitro selection methods. Structural studies of nucleic acid-small molecule complexes provide insight into both the principles of molecular... |
10359712 | Host-guest chemistry: combinatorial receptors. | A combinatorial approach to receptor design provides an expedient method to discover the most effective host-guest complexes from within a library. Recent advances focus on generation of larger libraries, facile detection, combinatorial catalysis and the formation of dynamic receptor libraries. |
10359788 | Acute cholesterol depletion inhibits clathrin-coated pit budding. | Many biologically important macromolecules are internalized into cells by clathrin-coated pit endocytosis. The mechanism of clathrin-coated pit budding has been investigated intensively, and considerable progress has been made in characterizing the proteins involved in internalization. Membrane lipid composition and th... |
10358081 | Structural insight into a quinolone-topoisomerase II-DNA complex. Further evidence for a 2:2 quinobenzoxazine-mg2+ self-assembly model formed in the presence of topoisomerase ii. | Quinobenzoxazine A-62176, developed from the antibacterial fluoroquinolones, is active in vitro and in vivo against murine and human tumors. It has been previously claimed that A-62176 is a catalytic inhibitor of mammalian topoisomerase II that does not stabilize the cleaved complex. However, at low drug concentrations... |
10348846 | Maltose metabolism in the hyperthermophilic archaeon Thermococcus litoralis: purification and characterization of key enzymes. | Maltose metabolism was investigated in the hyperthermophilic archaeon Thermococcus litoralis. Maltose was degraded by the concerted action of 4-alpha-glucanotransferase and maltodextrin phosphorylase (MalP). The first enzyme produced glucose and a series of maltodextrins that could be acted upon by MalP when the chain ... |
10359614 | Direct visualization of a protein nuclear architecture. | Whether the cell nucleus is organized by an underlying architecture analagous to the cytoskeleton has been a highly contentious issue since the original isolation of a nuclease and salt-resistant nuclear matrix. Despite electron microscopy studies that show that a nuclear architecture can be visualized after fractionat... |
10359609 | The PDZ domain of the LIM protein enigma binds to beta-tropomyosin. | PDZ and LIM domains are modular protein interaction motifs present in proteins with diverse functions. Enigma is representative of a family of proteins composed of a series of conserved PDZ and LIM domains. The LIM domains of Enigma and its most related family member, Enigma homology protein, bind to protein kinases, w... |
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