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10466786 | Evidence for the role of His-142 of protein 1C in the acid-induced disassembly of foot-and-mouth disease virus capsids. | Foot-and-mouth disease virus (FMDV) capsids are inherently labile under mildly acidic conditions, dissociating to pentamers at pH values in the region of 6.5, with the release of protein 1A and the viral RNA. This acid-induced disassembly is thought to be required for the entry of the virus genome into the host cell. P... |
10459018 | Analysis of CD44-containing lipid rafts: Recruitment of annexin II and stabilization by the actin cytoskeleton. | CD44, the major cell surface receptor for hyaluronic acid (HA), was shown to localize to detergent-resistant cholesterol-rich microdomains, called lipid rafts, in fibroblasts and blood cells. Here, we have investigated the molecular environment of CD44 within the plane of the basolateral membrane of polarized mammary e... |
10460167 | Conformation of bacteriochlorophyll molecules in photosynthetic proteins from purple bacteria. | Fourier transform near-infrared resonance Raman spectroscopy can be used to obtain information on the bacteriochlorophyll a (BChl a) molecules responsible for the redmost absorption band in photosynthetic complexes from purple bacteria. This technique is able to distinguish distortions of the bacteriochlorin macrocycle... |
10461749 | Synthesis and cytostatic activities of didemnin derivatives. | The highly cytostatic didemnins contain a 23-membered cyclopeptolide with a side chain attached to the backbone through the amine group of threonine. Thirty-six derivatives varying the side chain were prepared, but only compounds with D-MeLeu attached to threonine show remarkable biological activities. To protect the m... |
10455198 | Properties of a cyclodextrin-specific, unusual porin from Klebsiella oxytoca. | The function of CymA, 1 of the 10 gene products involved in cyclodextrin uptake and metabolism by Klebsiella oxytoca, was characterized. CymA is essential for growth on cyclodextrins, but it can also complement the deficiency of a lamB (maltoporin) mutant of Escherichia coli for growth on linear maltodextrins, indicati... |
10455323 | Spontaneously hypertensive rats cholinergic hyper-responsiveness: central and peripheral pharmacological mechanisms. | 1. The mechanisms and the subtypes of muscarinic receptors implicated in the cardiovascular effects of physostigmine were investigated in conscious normotensive and spontaneously hypertensive rats. 2. Intravenous (i.v.) physostigmine (50 microg kg-1) induced in both strains a long pressor response, accompanied by a bra... |
10455884 | Neutrophils are primed for cytotoxicity and resist apoptosis in injured patients at risk for multiple organ failure. | <h4>Background</h4>Postinjury multiple organ failure (MOF) is the result of a dysregulated systemic inflammatory response in which primed neutrophils (PMNs) are sequestered in tissues, vulnerable to activation through secondary insults. Apoptosis is critical to the normal clearance of these sequestered PMNs. Conversely... |
10454640 | Conservation, localization and expression of HopZ, a protein involved in adhesion of Helicobacter pylori. | From a sarkosyl-insoluble outer membrane fraction prepared from the Helicobacter pylori strain ATCC 43504, 19 proteins could be sequenced N-terminally by Edman degradation. Oligonucleotides were deduced and used for screening of a genomic library. From the isolated genes, five code for different members of a H.pylori o... |
10454608 | Isolation and characterisation of the cDNA encoding a glycosylated accessory protein of pea chloroplast DNA polymerase. | The cDNA encoding p43, a DNA binding protein from pea chloroplasts (ct) that binds to cognate DNA polymerase and stimulates the polymerase activity, has been cloned and characterised. The characteristic sequence motifs of hydroxyproline-rich glyco-proteins (HRGP) are present in the cDNA corres-ponding to the N-terminal... |
10454606 | Direct identification of NH...N hydrogen bonds in non-canonical base pairs of RNA by NMR spectroscopy. | It is shown that the recently developed quantitative J(NN)HNN-COSY experiment can be used for the direct identification of hydrogen bonds in non-canonical base pairs in RNA. Scalar(2h)J(NN)couplings across NH.N hydrogen bonds are observed in imino hydrogen bonded GA base pairs of the hpGA RNA molecule, which contains a... |
10454597 | Oligonucleotide dendrimers: stable nano-structures. | DNA dendrimers with two, three, six, nine or 27 arms were reassociated as complementary pairs in solution or with an array of complementary oligonucleotides on a solid support. In all cases, duplex stabilities were greater than those of unbranched molecules of equal length. A theoretical treatment for the process of di... |
10452892 | Mutational analysis of the thermostable arginine repressor from Bacillus stearothermophilus: dissecting residues involved in DNA binding properties. | Recently the crystal structure of the DNA-unbound form of the full-length hexameric Bacillus stearothermophilus arginine repressor (ArgR) has been resolved, providing a possible explanation for the mechanism of arginine-mediated repressor-operator DNA recognition. In this study we tested some of these functional predic... |
10449780 | A molecular sensor that allows a gut commensal to control its nutrient foundation in a competitive ecosystem. | Little is known about how members of the indigenous microflora interact with their mammalian hosts to establish mutually beneficial relationships. We have used a gnotobiotic mouse model to show that Bacteroides thetaiotaomicron, a component of the intestinal microflora of mice and humans, uses a repressor, FucR, as a m... |
10449742 | Protein design is a key factor for subunit-subunit association. | Fundamental questions about role of the quaternary structures are addressed by using a statistical mechanics off-lattice model of a dimer protein. The model, in spite of its simplicity, captures key features of the monomer-monomer interactions revealed by atomic force experiments. Force curves during association and di... |
10449737 | Redox-linked transient deprotonation at the binuclear site in the aa(3)-type quinol oxidase from Acidianus ambivalens: implications for proton translocation. | The hyperthermophilic archaeon Acidianus ambivalens expresses a membrane-bound aa(3)-type quinol oxidase, when grown aerobically, that we have studied by resonance Raman spectroscopy. The purified aa(3) oxidase, which does not contain bound quinol, undergoes a reversible slow conformational change at heme a(3) upon red... |
10449726 | The accessory subunit of mtDNA polymerase shares structural homology with aminoacyl-tRNA synthetases: implications for a dual role as a primer recognition factor and processivity clamp. | The accessory subunit of the heterodimeric mtDNA polymerase (polgamma) from Drosophila embryos is required to maintain the structural integrity or catalytic efficiency of the holoenzyme. cDNAs for the accessory subunit from Drosophila, man, mouse, and rat have been identified, and comparative sequence alignment reveals... |
10449722 | Phosphorylated tau can promote tubulin assembly. | Phosphorylation can affect the function of microtubule-associated protein tau. Here, the human brain tau with 441 amino acids was phosphorylated by cyclic-AMP-dependent protein kinase (PKA) or glycogen synthase kinase-3beta. PKA-phosphorylated tau (2.7 mol phosphates/mol) does not promote tubulin assembly as judged by ... |
10449715 | Aeolotopic interactions of globular proteins. | Protein crystallization, aggregation, liquid-liquid phase separation, and self-assembly are important in protein structure determination in the industrial processing of proteins and in the inhibition of protein condensation diseases. To fully describe such phase transformations in globular protein solutions, it is nece... |
10447950 | Molecular recognition in nicotinic acetylcholine receptors: the importance of pi-cation interactions. | We explore the significance of pi-cation interactions in the binding of ligands to nicotinic acetylcholine receptors. Specifically, the Austin method of semiempirical molecular orbital theory is utilized to estimate the interaction of aromatic amino acid side chains with the cation-containing heterocyclic ring fragment... |
10447949 | Chiral resolution and stereospecificity of 6-phenyl-4-phenylethynyl- 1,4-dihydropyridines as selective A(3) adenosine receptor antagonists. | Racemic 6-phenyl-4-phenylethynyl-1,4-dihydropyridine derivatives have been shown to be highly selective A(3) adenosine receptor antagonists (Jiang et al. J. Med. Chem. 1997, 40, 2596-2608). Methods for resolving the optical isomers at the C4 position, involving selective crystallization or chromatographic separation of... |
10449417 | X-ray structure of aminopeptidase A from Escherichia coli and a model for the nucleoprotein complex in Xer site-specific recombination. | The structure of aminopeptidase A (PepA), which functions as a DNA-binding protein in Xer site-specific recombination and in transcriptional control of the carAB operon in Escherichia coli, has been determined at 2.5 A resolution. In Xer recombination at cer, PepA and the arginine repressor (ArgR) serve as accessory pr... |
10452613 | Denaturant mediated unfolding of both native and molten globule states of maltose binding protein are accompanied by large deltaCp's. | Maltose binding protein (MBP) is a large, monomeric two domain protein containing 370 amino acids. In the absence of denaturant at neutral pH, the protein is in the native state, while at pH 3.0 it forms a molten globule. The molten globule lacks a tertiary circular dichroism signal but has secondary structure similar ... |
10452604 | The disulfide-coupled folding pathway of apamin as derived from diselenide-quenched analogs and intermediates. | The sequence of apamin, an 18 residue bee venom toxin, encloses all the information required for the correct disulfide-coupled folding into the cystine-stabilized alpha-helical motif. Three apamin analogs, each containing a pair of selenocysteine residues replacing the related cysteines, were synthesized to mimic the t... |
10450162 | Fragmentation reactions in the mass spectrometry analysis of neutral oligosaccharides. | A method is described to obtain multicollision dissociation threshold (MCDT) values. These values provide relative reaction thresholds for dissociation in the three major gas-phase fragmentation reactions of oligosaccharides complexed to alkali metal ions. The quasimolecular ions are produced using matrix-assisted lase... |
10450159 | Electrostatic immobilization of glucose oxidase in a weak acid, polyelectrolyte hyperbranched ultrathin film on gold: fabrication, characterization, and enzymatic activity. | In this paper we show that hyperbranched polymers can be used as a host matrix for electrostatic entrapment of enzymes. Specifically, amine-functionalized glucose oxidase (GOx+) and horseradish peroxidase, as well as poly(amidoamine) dendrimer-modified horseradish peroxidase, reversibly sorb into polyanionic, hyperbran... |
10450152 | Effective use of molecular recognition in gas sensing: results from acoustic wave and in situ FT-IR measurements. | To probe directly the analyte/film interactions that characterize molecular recognition in gas sensors, we recorded changes to the in situ surface vibrational spectra of specifically functionalized surface acoustic wave (SAW) devices concurrently with analyte exposure and SAW measurement of the extent of sorption. Four... |
10447880 | Resistance mutations reveal the atovaquone-binding domain of cytochrome b in malaria parasites. | Atovaquone represents a class of antimicrobial agents with a broad-spectrum activity against various parasitic infections, including malaria, toxoplasmosis and Pneumocystis pneumonia. In malaria parasites, atovaquone inhibits mitochondrial electron transport at the level of the cytochrome bc1 complex and collapses mito... |
10444074 | Role of cholesterol in formation and function of a signaling complex involving alphavbeta3, integrin-associated protein (CD47), and heterotrimeric G proteins. | Integrin-associated protein (CD47) is a multiply membrane spanning member of the immunoglobulin superfamily that regulates some adhesion-dependent cell functions through formation of a complex with alphavbeta3 integrin and trimeric G proteins. Cholesterol is critical for the association of the three protein components ... |
10441473 | The 90-kDa junctional sarcoplasmic reticulum protein forms an integral part of a supramolecular triad complex in skeletal muscle. | Although it is well established that voltage-sensing of the alpha(1)-dihydropyridine receptor triggers Ca(2+)-release via the ryanodine receptor during excitation-contraction coupling in skeletal muscle fibers, it remains to be determined which junctional components are responsible for the assembly, maintenance, and st... |
10445876 | Mutations in the highly conserved GGQ motif of class 1 polypeptide release factors abolish ability of human eRF1 to trigger peptidyl-tRNA hydrolysis. | Although the primary structures of class 1 polypeptide release factors (RF1 and RF2 in prokaryotes, eRF1 in eukaryotes) are known, the molecular basis by which they function in translational termination remains obscure. Because all class 1 RFs promote a stop-codon-dependent and ribosome-dependent hydrolysis of peptidyl... |
10438774 | In Thermoanaerobacterium thermosulfurigenes EM1 S-layer homology domains do not attach to peptidoglycan. | Three exocellular enzymes of Thermoanaerobacterium thermosulfurigenes EM1 possess a C-terminal triplicated sequence related to a domain of bacterial cell surface proteins (S-layer proteins). At least one copy of this sequence, named the SLH (for S-layer homology) domain, is also present at the N terminus of the S-layer... |
10436075 | Rat hippocampal neurons are critically involved in physiological improvement of memory processes induced by cholecystokinin-B receptor stimulation. | The involvement in memory processes of the neuropeptide cholecystokinin (CCK) through its interaction with the CCK-B receptors was studied. The two-trial recognition memory task was used. Control animals showed recognition memory after a 2 hr time interval but not after a 6 hr time interval between the two trials. The ... |
10436004 | Allosteric voltage gating of potassium channels II. Mslo channel gating charge movement in the absence of Ca(2+). | Large-conductance Ca(2+)-activated K(+) channels can be activated by membrane voltage in the absence of Ca(2+) binding, indicating that these channels contain an intrinsic voltage sensor. The properties of this voltage sensor and its relationship to channel activation were examined by studying gating charge movement fr... |
10434139 | Interaction of cyclomaltononaose (delta-CD) with several drugs. | The effects of delta-cyclodextrin (delta-CD; cyclomaltononaose) on solubility of 14 drugs that are slightly soluble or insoluble in water were studied and compared with those of conventional cyclodextrins (CDs) such as alpha-cyclodextrin (alpha-CD), beta-cyclodextrin (beta-CD), and gamma-cyclodextrin (gamma-CD). In gen... |
10434135 | Self-assembling nanospheres of hydrophobized pullulans in water. | In this report, we have prepared self-assembling nanospheres of hydrophobized pullulans. Pullulan acetate as a hydrophobized pullulan was synthesized by acetylation of pullulan and characterized by Fourier transform infrared (FTIR) measurement. From the results of photon correlation spectroscopy (PCS), hydrophobized pu... |
10434131 | The influence of beta-cyclodextrin on the solubility of chlorthalidone and its enantiomers. | The solubility of chlorthalidone in 16 solvent systems was determined in the absence and presence of different amounts of beta-cyclodextrin (beta-CD). Chlorthalidone (CT) was shown to be more soluble in hydrophilic organic solvents, with the highest solubility in ethylacetate (EtOAc) saturated with water. The solubilit... |
10430897 | Intrinsic beta-sheet propensities result from van der Waals interactions between side chains and the local backbone. | The intrinsic secondary structure-forming propensities of the naturally occurring amino acids have been measured both experimentally in host-guest studies and statistically by examination of the protein structure databank. There has been significant progress in understanding the origins of intrinsic alpha-helical prope... |
10430870 | An unusual structural motif of antimicrobial peptides containing end-to-end macrocycle and cystine-knot disulfides. | Four macrocyclic cystine-knot peptides of 29-31 residues, kalata, circulin A and B (CirA and CirB), and cyclopsychotride, have been isolated from coffee plants but have undetermined physiological functions. These macrocycles and 10 of their analogs prepared by chemical synthesis were tested against nine strains of micr... |
10430538 | Ultraviolet spectroscopic estimation of microenvironments and bitter tastes of oxyphenonium bromide in cyclodextrin solutions. | The UV absorbance and bitter taste of oxyphenonium bromide (OB), an antiacetylcholine drug, in cyclodextrin (CD) solutions are measured, and the local environment of the binding site and the reduction of the bitter taste intensity are quantitatively estimated from the UV data. The UV spectrum of OB is changed with the ... |
10428984 | Comparison of the capacity of beta-cyclodextrin derivatives and cyclophanes to shuttle cholesterol between cells and serum lipoproteins. | Previous studies from this laboratory have demonstrated that low concentrations of cyclodextrins (<1.0 mm), when added to serum, act catalytically as cholesterol shuttles to accelerate the exchange of free cholesterol between cells and serum lipoproteins. As cholesterol shuttles, cyclodextrins have the potential to ser... |
10428976 | N-terminal domain of apolipoprotein B has structural homology to lipovitellin and microsomal triglyceride transfer protein: a "lipid pocket" model for self-assembly of apob-containing lipoprotein particles. | The process of assembly of apolipoprotein (apo) B-containing lipoprotein particles occurs co-translationally after disulfide-dependent folding of the N-terminal domain of apoB but the mechanism is not understood. During a recent database search for protein sequences that contained similar amphipathic beta strands to ap... |
10428963 | Kinetics and peptide dependency of the binding of the inhibitory NK receptor CD94/NKG2-A and the activating receptor CD94/NKG2-C to HLA-E. | The lytic function of human natural killer (NK) cells is markedly influenced by recognition of class I major histocompatibility complex (MHC) molecules, a process mediated by several types of activating and inhibitory receptors expressed on the NK cell. One of the most important of these mechanisms of regulation is the... |
10428957 | Interaction of the yeast gamma-tubulin complex-binding protein Spc72p with Kar1p is essential for microtubule function during karyogamy. | The spindle pole body component Kar1p has a function in nuclear fusion during conjugation, a process known as karyogamy. The molecular role of Kar1p during this process is poorly understood. Here we show that the yeast gamma-tubulin complex-binding protein Spc72p interacts directly with the N-terminal domain of Kar1p, ... |
10428838 | Intracellular phosphotyrosine induction by major histocompatibility complex class II requires co-aggregation with membrane rafts. | Cross-linking MHC class II molecules human leukocyte antigen (HLA-DR) on the surface of THP-1 cells was found to induce their entry into the glycolipid-enriched membrane fraction of the plasma membrane. At the cellular level, this resulted in the synergistic co-aggregation of class II with cholera toxin, a marker of me... |
10427625 | In vitro cell culture systems as the basis for an extracorporeal blood purification strategy in multiorgan failure treatment. | Multiorgan failure (MOF) based on septic processes is very common but prognostically an extremely severe disease that has to be treated exclusively under intensive care conditions. Extracorporeal blood purification (ECBP) using specific and efficient systems such as the microspheres based detoxification system (MDS) (A... |
10425377 | Solid state studies of drug-cyclodextrin inclusion complexes in PEG 6000 prepared by a new method. | The melting method was investigated as a possible method for producing drug-cyclodextrin (CD) inclusion compounds in a carrier. Various solid dispersions of alpha-, beta- and gamma-CD in polyethylene glycol (PEG) 6000 with and without the addition of 5% w/w indomethacin or griseofulvin were prepared using the original ... |
10425336 | Factors affecting membrane-controlled drug release for an osmotic pump tablet (OPT) utilizing (SBE)(7m)-beta-CD as both a solubilizer and osmotic agent. | <h4>Purpose</h4>The purpose of this study was to define membrane controlling factors responsible for drug release from a controlled-porosity osmotic pump tablet (OPT) that utilizes a sulfobutyl ether-beta-cyclodextrin, (SBE)(7m)-beta-CD, as both a solubilizing and osmotic agent.<h4>Method</h4>The OPT was spray coated w... |
10423359 | Consequences of (129)Xe-(1)H cross relaxation in aqueous solutions. | We have investigated the transfer of polarization from (129)Xe to solute protons in aqueous solutions to determine the feasibility of using hyperpolarized xenon to enhance (1)H sensitivity in aqueous systems at or near room temperatures. Several solutes, each of different molecular weight, were dissolved in deuterium o... |
10425023 | Determination of aspartic acid enantiomers in bio-samples by capillary electrophoresis. | Enantiomeric separation and detection of D,L-aspartic acid (Asp) derivatized with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F) by capillary electrophoresis (CE) using modified cyclodextrins as chiral selectors was studied. Heptakis(2,3, 6-tri-O-methyl)-beta-cyclodextrin(TM-beta-CD) was most effective for enantiomeric ... |
10423448 | Connection between the taxonomic substates and protonation of histidines 64 and 97 in carbonmonoxy myoglobin. | Infrared spectra of heme-bound CO in sperm whale carbonmonoxy myoglobin and two mutants (H64L and H97F) were studied in the pH range from 4.2 to 9.5. Comparison of the native protein with the mutants shows that the observed pH effects can be traced to protonations of two histidine residues, H64 and H97, near the active... |
10423445 | Kinetics processivity and the direction of motion of Ncd. | The kinetic mechanism of the nonclaret disjunctional protein (Ncd) motor was investigated using the dimer termed MC1 (residues 209-700), which has been shown to exhibit negative-end directed motility (Chandra et al., 1993). The kinetic properties are similar to those of the monomeric Ncd motor domain (Pechatnikova and ... |
10423436 | Phase diagram, stability, and overcharging of lamellar cationic lipid-DNA self-assembled complexes. | Cationic lipid-DNA (CL-DNA) complexes comprise a promising new class of synthetic nonviral gene delivery systems. When positively charged, they attach to the anionic cell surface and transfer DNA into the cell cytoplasm. We report a comprehensive x-ray diffraction study of the lamellar CL-DNA self-assemblies as a funct... |
10423435 | Effect of hydrophobic surfactant peptides SP-B and SP-C on binary phospholipid monolayers. I. Fluorescence and dark-field microscopy. | The influence of the hydrophobic proteins SP-B and SP-C, isolated from pulmonary surfactant, on the morphology of binary monomolecular lipid films containing phosphocholine and phosphoglycerol (DPPC and DPPG) at the air-water interface has been studied using epifluorescence and dark-field microscopy. In contrast to pre... |
10423429 | Ultrastructural characterization of peptide-induced membrane fusion and peptide self-assembly in the lipid bilayer. | The peptide sequence B18, derived from the membrane-associated sea urchin sperm protein bindin, triggers fusion between lipid vesicles. It exhibits many similarities to viral fusion peptides and may have a corresponding function in fertilization. The lipid-peptide and peptide-peptide interactions of B18 are investigate... |
10423414 | Conformational equilibria of alkanes in aqueous solution: relationship to water structure near hydrophobic solutes. | Conformational free energies of butane, pentane, and hexane in water are calculated from molecular simulations with explicit waters and from a simple molecular theory in which the local hydration structure is estimated based on a proximity approximation. This proximity approximation uses only the two nearest carbon ato... |
10423859 | Binding affinities of gallotannin analogs with bovine serum albumin: ramifications for polyphenol-protein molecular recognition. | A series of gallotannin analogs were prepared by chemical synthesis, and their affinity for the test-case protein bovine serum albumin was measured by equilibrium dialysis. The structure/activity data obtained suggest that the naturally occurring gallotannins, in fact, do not represent the optimal protein recognition a... |
10421775 | Characterization of potential endocrine-related health effects at low-dose levels of exposure to PCBs. | This article addresses issues related to the characterization of endocrine-related health effects resulting from low-level exposures to polychlorinated biphenyls (PCBs). It is not intended to be a comprehensive review of the literature but reflects workshop discussions. "The Characterizing the Effects of Endocrine Disr... |
10419977 | Involvement of the RNA polymerase alpha-subunit C-terminal domain in LuxR-dependent activation of the Vibrio fischeri luminescence genes. | LuxR is a sigma(70) RNA polymerase (RNAP)-dependent transcriptional activator that controls expression of the Vibrio fischeri lux operon in response to an acylhomoserine lactone-cell density signal. We have investigated whether the alpha-subunit C-terminal domain (alphaCTD) of RNAP is required for LuxR activity. A puri... |
10419973 | Amino acid residues involved in the functional integrity of Escherichia coli methionine aminopeptidase. | Amino acid residues in the metal-binding and putative substrate-binding sites of Escherichia coli methionine aminopeptidase (MAP) were mutated, and their effects on the function of the enzyme were investigated. Substitution of any amino acid residue at the metal-binding site resulted in complete loss of the two cobalt ... |
10417506 | Serum concentrations of tramadol enantiomers during patient-controlled analgesia. | <h4>Aims</h4>Tramadol, a centrally acting analgesic, is used as a racemate containing 50% of a (+)- and 50% of a (-)-enantiomer. This paper presents the pharmacokinetic results of postoperative patient-controlled analgesia using (+)-tramadol, (-)-tramadol or the racemate.<h4>Methods</h4>Ninety-eight patients recovering... |
10417146 | The cysteine-rich region of the Entamoeba histolytica adherence lectin (170-kilodalton subunit) is sufficient for high-affinity Gal/GalNAc-specific binding in vitro. | Adherence of Entamoeba histolytica trophozoites to colonic mucin, epithelium, and other target cells is mediated by the amebic Gal/GalNAc lectin. We constructed in vitro expression vectors containing full-length (residues 1 to 1280), cysteine-poor (1 to 353 and 1 to 480), and cysteine-rich (356 to 1143 and 480 to 900) ... |
10409733 | Differentiation-induced internal translation of c-sis mRNA: analysis of the cis elements and their differentiation-linked binding to the hnRNP C protein. | In previous reports we showed that the long 5' untranslated region (5' UTR) of c-sis, the gene encoding the B chain of platelet-derived growth factor, has translational modulating activity due to its differentiation-activated internal ribosomal entry site (D-IRES). Here we show that the 5' UTR contains three regions wi... |
10400721 | The furin protease cleavage recognition sequence of Sindbis virus PE2 can mediate virion attachment to cell surface heparan sulfate. | Cell culture-adapted Sindbis virus strains attach to heparan sulfate (HS) receptors during infection of cultured cells (W. B. Klimstra, K. D. Ryman, and R. E. Johnston, J. Virol. 72:7357-7366, 1998). At least three E2 glycoprotein mutations (E2 Arg 1, E2 Lys 70, and E2 Arg 114) can independently confer HS attachment in... |
10400720 | Second-site reversion of a human immunodeficiency virus type 1 reverse transcriptase mutant that restores enzyme function and replication capacity. | Nonconservative substitutions for Tyr-115 in the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1) lead to enzymes displaying lower affinity for deoxynucleoside triphosphates (dNTPs) (A. M. Martín-Hernández, E. Domingo, and L. Menéndez-Arias, EMBO J. 15:4434-4442, 1996). Several mutations at thi... |
10400719 | The gag domains required for avian retroviral RNA encapsidation determined by using two independent assays. | The Rous sarcoma virus (RSV) Gag precursor polyprotein is the only viral protein which is necessary for specific packaging of genomic RNA. To map domains within Gag which are important for packaging, we constructed a series of Gag mutations in conjunction with a protease (PR) active-site point mutation in a full-length... |
34237853 | Cation-Templated Self-Assembly of a Lipophilic Deoxyguanosine: Solution Structure of a K<sup>+</sup>-dG<sub>8</sub> Octamer. | The lipophilic nucleoside 3',5'-didecanoyl-2'-deoxyguanosine, dG <b>1</b>, extracts potassium salts from water into organic solvents. The K<sup>+</sup> extraction drives the self-association of dG <b>1</b> to give G-quartet structures. A series of <sup>1</sup>H NMR experiments indicates that the identity of the assembl... |
34182708 | Template-Mediated Synthesis of a Polymeric Receptor Specific to Amino Acid Sequences. | Polymeric receptors prepared by a combination of covalent and noncovalent imprinting show high selectivity for the amino acid sequence of the template (see schematic representation of the binding of the tripeptide Lys-Trp-Asp). |
34182707 | A Giant Carceplex Permanently Entraps Three Organic Molecules. | Capping a trimer of cavitands at the top and bottom creates a large carceplex which contains three permanently entrapped N,N-dimethylformamide (DMF) molecules (shown schematically). Room-temperature NMR spectra and CPK models indicate that the DMF molecules are free to move within the carceplex cavity and thus create a... |
34182693 | N-Oxidation of Epothilone A-C and O-Acyl Rearrangement to C-19- and C-21-Substituted Epothilones. | A bothersome side reaction in the last step of a total synthesis of epothilone led to the formation of the thiazol-N-oxide 1. Obtained from epothilones prepared by fermentation, these biologically active N-oxides allow the extremely short synthesis of the highly active epothilones 2 with modified side chains by an O-ac... |
34182692 | Chelated Bisphosphites with a Calix[4]arene Backbone: New Ligands for Rhodium-Catalyzed Low-Pressure Hydroformylation with Controlled Regioselectivity. | Extremely high regioselectivities were achieved in the rhodium-catalyzed low-pressure hydroformylation of 1-octene to n-nonanal with chelate bisphosphites that contain a p-tert-butylcalix[4]arene backbone (shown in the picture). It was possible to tailor the structures and ultimately the catalytic properties of these c... |
34182686 | Interaction of a PDZ Protein Domain with a Synthetic Library of All Human Protein C Termini. | New interaction partners of a PDZ protein domain were identified through use of a library made up of all known human protein C-terminal peptides ("P" in the schematic representation). The library was displayed on a cellulose membrane by positional resolution of inverted peptides. |
34182684 | Dendritically Cross-Linking Chiral Ligands: High Stability of a Polystyrene-Bound Ti-TADDOLate Catalyst with Diffusion Control. | A new type of heterogeneous, polystyrene-bound catalyst is introduced: A cross-linking, dendritic ligand, the TADDOL 1, is copolymerized with styrene, loaded with titanate, and used for the enantioselective catalysis of the addition of Et<sub>2</sub>Zn to PhCHO. The polymer-bound catalyst has an unprecedented efficienc... |
34182676 | S-Cylindrophanes: From Metal Tweezers to Metal Sandwiches. | Inclusion of Ag<sup>I</sup> and Cu<sup>I</sup> ions by the preorganized cylindrophane cage compound 1 provides the first examples of bis(η<sup>6</sup>) sandwich complexes of these metals. Locked in a trigonal-planar heteroatom ligand field, the guest ions are shown by NMR spectroscopy to withdraw electron density from ... |
34182667 | A Polymer Guest Transforms Clathrate Cages into Channels: The Single-Crystal X-Ray Structure of Tetra-n-butylammonium Polyacrylate Hydrate, nBu<sub>4</sub>NPA⋅40 H<sub>2</sub>O. | The stacking of hydrate cages into channels is effected by the incorporation of polyacrylic acid together with tetra-n-butylammonium hydroxide into a hydrate lattice. The polymer chain (shown in the diagram as large circles) lies in the channel in such a way that some of the carboxy groups displace water molecules from... |
34182658 | Expanded Radialenes: Modular Synthesis and Characterization of Cross-Conjugated Enyne Macrocycles. | Stepwise palladium-catalyzed cross-coupling between terminal alkynes and vinyl triflates afforded the first cross-conjugated enyne macrocycles constructed of 3-alkylidene-1-propynyl [-C≡C-C(=CR<sub>2</sub>)-] building blocks, namely, the expanded radialene 1 and the hybrid radialene 2. |
23015251 | Tetrapyrrolic Glycosylated Macrocycles for an Application in PDT. | The synthesis and characterization of amphiphilic glycoconjugated porphyrins, benzochlorin, and azaporphyrins were reported. Among these molecules, several were found to be efficient photosensitizers in an in vitro assay using the human tumoral cell line HT29. Moreover, glycosylated benzochlorin and azaporphyrins, whos... |
22346390 | Gene therapy for HIV infections: Intracellular immunization. | Despite significant advances in the treatment of human immunodeficiency virus (HIV) infection in the past 10 years, it remains an incurable disease. The inability of traditional drug-based therapies to inhibit HIV replication effectively for extended periods of time has stimulated intense research to develop novel appr... |
21662799 | Quantification of the Interaction between Charged Guest Molecules and Chemisorbed Monothiolated β-Cyclodextrins. | The quantification of small molecules in aqueous solution by surface bound supramolecular host molecules is an important goal in the research field of chemo- and biosensor development. In this paper we present an attempt to quantify the interaction of different charged guest molecules with chemisorbed monothiolated β-c... |
18967654 | Extraction equilibria of various metal picrates with 19-crown-6 between benzene and water. Effect of the extra methylene group on extraction ability and selectivity. | The overall extraction equilibrium constants (K(ex)) of picrates of Li(+), Na(+), K(+), Rb(+), Cs(+), Ag(+), Tl(+), and Sr(2+)with 19-crown-6 (19C6) were determined between benzene and water at 25 degrees C. The K(ex) values were analyzed into the constituent equilibrium constants, i.e. the extraction constant of picri... |
18967649 | Synthesis, complexation, and fluorescence behavior of armed crown ethers carrying naphthyl group. | Armed crown ethers (1-4) bonding through an amine, amide, ether, or ester linkage to naphthyl group were found to display unique photophysical properties in the presence of guest salts. Complexation of PET fluoroionophores (1a and 1b) with Zn(2+) increased the fluorescence intensities of the host by a factor of 2.4 and... |
18967644 | Synchronous-derivative phosphorimetric determination of 1- and 2-naphthol in irrigation water by employing beta-cyclodextrin. | A room-temperature phosphorimetric (RTP) study of the inclusion process between 1- and 2-naphthol, beta-cyclodextrin (beta-CD) and 3-bromo-1-propanol as heavy atom pertuber has been performed. Experimental conditions were optimized for the formation of trimolecular complexes with lifetimes of 10.82 and 9.41 ms for 1- a... |
18967633 | Influence of the guests, the type and degree of substitution on inclusion complex formation of substituted beta-cyclodextrins. | The stability of inclusion complexes (i.e. the measure of molecular recognition between a guest and (beta-cyclodextrin, CD) is highly influenced by the fit of the guest into the cavity of the host and by secondary bonds among the functional groups getting in close connection. The guests themselves influence these inter... |
18967628 | Spectrophotometric study of the reaction of iodine and bromine with two new macrocycle diamides and di-ortho methoxybenzoyl thiourea in chloroform solution. | The complex formation reactions of iodine and bromine with two new macrocycle diamides (1 and 2) and di-ortho methoxybenzoyl thiourea (DOMBT) (3) have been studied spectrophotometrically at various temperatures in chloroform solution. In all cases the resulting 1:2 (macrocycle to halogen) or (DOMBT to halogen) molecula... |
18967623 | Spectrophotometric study on the supramolecular interactions of nile blue sulphate with nucleic acids. | The supramolecular interaction of nile blue sulphate (NBS) with nucleic acids was studied by investigating the characteristics of the interaction absorption spectra on the basis of the drug binding process in organic system in which small amount of drug interacting with large amount of biological macromolecules involve... |
10411498 | Electronically configurable molecular-based logic gates | Logic gates were fabricated from an array of configurable switches, each consisting of a monolayer of redox-active rotaxanes sandwiched between metal electrodes. The switches were read by monitoring current flow at reducing voltages. In the "closed" state, current flow was dominated by resonant tunneling through the el... |
10362479 | Structure Formation in Polymer-Modified Liquid Crystals. | The objective is the investigation of the influence of two different polymers in a lamellar liquid crystalline sodium dodecyl sulfate (SDS)/decanol/water system. The polymers are, on the one hand, uncharged poly(ethylene glycol) (PEG), whose molecular weight is varied, and, on the other hand, a polycation with differin... |
11674632 | in- and out-Cyclophanes Bearing Non-Hydrogen Bridgehead Substituents. | The syntheses of several cyclophanes containing a triaryl(element) "top" poised above a trisubstituted benzene "base" were carried out to install a non-hydrogen atom as a substituent on a bridgehead with an inwardly directed geometry. Most significantly, the tribenzo 6-fluoro-6-sila-2,10,19-trithia[5(6,14)][11]metacycl... |
11674608 | Synthesis of Catenane Structures via Ring-Closing Metathesis. | This study presents a detailed description of a synthetic strategy to obtain catenane architectures through ring-closing metathesis. The approach is based on phenanthroline-based ligands containing terminal olefinic units that were designed to coordinate in a tetrahedral arrangement around a copper atom. Treatment of t... |
11674593 | Manganese Tetraphenylporphyrin-Catalyzed Stereoselective Epoxidation of Thymidine Nucleosides. | Manganese 2,6-disubstituted tetraphenylporphyrins, bearing halogen atoms on the beta-positions, have been used as catalysts for the first described stereoselective epoxidation of thymidine nucleosides. The oxidations were carried out using dimethyldioxirane (DMDO) as the oxygen atom donor. The diastereoisomeric ratio o... |
11671092 | A Supramolecular Synthon for H-Bonded Transition Metal Arrays. | The heterocycle melamine appended to a 14-membered polyazamacrocyclic copper(II) complex ring exhibits a strong propensity for ordered arrays driven by H-bonding forces. In this work, the X-ray crystal structures of three distinctly different arrays based on the same macrocyclic complex are reported, comprising cocryst... |
11671080 | Molecular Shape and Solvation of the Lacunar, Saddle-Shaped, and Planar Metal Cyclidene Complexes: Molecular Dynamics Studies. | Molecular dynamics simulations have been used to study the three-dimensional distribution of methanol solvent molecules around three cobalt(II) cyclidene complexes differing in details of their ligand structures. The ligands are a planar unbridged 14-membered macrocycle in Co([14]Cyc), a saddle-shaped unbridged 16-memb... |
12552866 | [Determination of enantiomeric purity for epinephrine by high performance liquid chromatography]. | A procedure for the resolution of D,L-epinephrine and the determination of D-isomer ratio in a pharmaceutical formulation is described. The optical isomers of epinephrine were resolved by RP-HPLC with heptakis(2,6-di-O-methyl-beta-cyclodextrin) as a chiral mobile phase additives. The results showed that a correction fa... |
12552851 | [Chiral separation of thioglycidyl ether and glycidylselenide on cyclodextrin bonded stationary phase via high performance liquid chromatography]. | beta- Cyclodextrin bonded chiral stationary phases (CD-CSP) were prepared after the method of Armstrong (CD-CSP I) and of Huang Tianbao (CD-CSP II). With the separation of o-, m- p-nitroaniline, it was found that the chromatographic properties of CD-CSP II was superior to that of CD-CSP I. Three racemes of thioglycidyl... |
10527890 | Direct visualization of gram-negative bacterial lipopolysaccharide self-assembly. | Bacterial lipopolysaccharides (LPS) are outer cell wall components of gram-negative bacteria that may cause septic shock in mammals. The exact morphology of LPS when interacting with macromolecular complexes of the septic shock pathway in blood is still uncertain. Here, the geometry and morphology of hydrated bacterial... |
10822547 | Solid-phase SN2 macrocyclization reactions to form beta-turn mimics. | [formula: see text] Efficient solid-phase SN2 macrocyclization reactions were sought to facilitate preparations of focused libraries of beta-turn mimetics. A very efficient, but undesired, cyclization reaction to give five-membered ring lactams 4 was identified in attempts to use O-nucleophiles. Subsequent studies focu... |
10822531 | Unique "cradled barbell" complex between a secondary diammonium ion and bis(m-phenylene)-32-crown-10. | [formula: see text] The complexation between N,N'-dibenzyl(m-xylylene)diammonium bis(hexafluorophosphate) (2) and bis(m-phenylene)-32-crown-10 (5) was shown to occur in solution by nuclear magnetic resonance with 1:1 stoichiometry and a Ka value of 189 +/- 19 M-1. A crystal structure of 2:5 revealed a unique 1:1 "exo" ... |
10760033 | Role of the specific T-cell response for clearance and control of hepatitis C virus. | T cells are believed to be the main players in antiviral defence. To investigate the role of the specific CD4+ T cell response for clearance and control of the hepatitis C virus we studied patients with acute hepatitis C (AHC) during the phase of spontaneous viral clearance and during follow up after elimination of the... |
10736860 | Enhanced microdialysis recovery of some tricyclic antidepressants and structurally related drugs by cyclodextrin-mediated transport. | The enhanced microdialysis relative recovery (RR) of some hydrophobic tricyclic drugs (imipramine, desipramine, amitriptyline, carbamazepine and promethazine) is discussed. Enhanced RR was achieved by including a binding agent [beta-cyclodextrin (beta-CD) or 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CD)] in the microd... |
10724524 | Immunolocalization of elastin, collagen type I and type III, fibronectin, and vitronectin in extracellular matrix components of normal and myxomatous mitral heart valve chordae tendineae. | The identification, distribution, and localization of matrix proteins and the proteins associated with normal and degenerated elastic fibers and collagen fibrils of myxomatous chordae tendineae were studied with immunoelectron microscopy. Ultrathin sections of L R White-embedded tissue were processed by indirect immuno... |
10695097 | A comparison of nimesulide beta cyclodextrin and nimesulide in postoperative dental pain. | The aim of this study was to assess the efficacy and tolerability of single doses of nimesulide beta cyclodextrin compared with nimesulide in patients with dental pain following surgical procedures. This was a randomised, double-blind, between-patient, multicentre study involving 148 outpatients suffering from moderate... |
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