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11467546 | Advantages of external accumulation for electron capture dissociation in Fourier transform mass spectrometry. | A combination of external accumulation (XA) with electron capture dissociation (ECD) improves the electron capture efficiency, shortens the analysis time, and allows for rapid integration of multiple scans in Fourier transform mass spectrometry. This improves the signal-to-noise ratio and increases the number of detect... |
11466049 | Metallocyclodextrins as building blocks in noncovalent assemblies of photoactive units for the study of photoinduced intercomponent processes. | Cyclodextrin cups have been employed to build supramolecular systems consisting of metal and organic photoactive/redox-active components; the photoinduced communication between redox-active units assembled in water via noncovalent interactions is established. The functionalization of a beta-cyclodextrin with a terpyrid... |
11463296 | MacDonald [2 + 2]-type condensation with vicinal diketones: synthesis and properties of novel spiro-tricyclic porphodimethenes. | [structure: see text] Acid-catalyzed [2 + 2] condensation reactions of polycyclic aromatic vicinal diketones including aceanthrenequinone, phenathrenequinone, and pyrene-4,5-dione with 5-mesityldipyrromethanes are outlined, and this methodology provides a flexible entry to spiro-tricyclic porphodimethenes. The porphodi... |
11463261 | Transmembrane ion channels constructed of cholic acid derivatives. | A new class of supramolecular transmembrane ion channels was prepared by linking two amphiphilic cholic acid methyl ethers through biscarbamate bonds to afford bis(7,12-dimethyl-24-carboxy-3-cholanyl)-N,N'-xylylene dicarbamate 2 and bis[7,12-dimethyl-24-(N,N,N-trimethylethanaminium-2-carboxylate)-3-cholanyl]-N,N'-xylyl... |
11463245 | Supramolecular assemblies between macrocyclic porphyrin hexamers and star-shaped porphyrin arrays. | The syntheses of eight new star-shaped D(3)-symmetric arrays in which three 15-(pyrid-4-yl)porphyrin subunits are attached to the 1, 3, and 5 positions of a benzene core through linkers consisting of collinear repetitive phenylethynyl units have been carried out using Pd(0)-catalyzed coupling reactions. By the same pro... |
11463741 | Structure--function relationships in HIV-1 Nef. | The accessory Nef protein of HIV and SIV is essential for viral pathogenesis, yet it is perplexing in its multitude of molecular functions. In this review we analyse the structure-function relationships of motifs recently proposed to play roles in aspects of Nef modification, signalling and trafficking, and thereby to ... |
11461088 | Growing vascular endothelial cells express somatostatin subtype 2 receptors. | We hypothesized that non-proliferating (quiescent) human vascular endothelial cells would not express somatostatin receptor subtype 2 (sst 2) and that this receptor would be expressed when the endothelial cells begin to grow. To test this hypothesis, placental veins were harvested from 6 human placentas and 2 mm vein d... |
11459969 | Bacteriophage T4 gene 41 helicase and gene 59 helicase-loading protein: a versatile couple with roles in replication and recombination. | Bacteriophage T4 uses two modes of replication initiation: origin-dependent replication early in infection and recombination-dependent replication at later times. The same relatively simple complex of T4 replication proteins is responsible for both modes of DNA synthesis. Thus the mechanism for loading the T4 41 helica... |
11459956 | Topological challenges to DNA replication: conformations at the fork. | The unwinding of the parental DNA duplex during replication causes a positive linking number difference, or superhelical strain, to build up around the elongating replication fork. The branching at the fork and this strain bring about different conformations from that of (-) supercoiled DNA that is not being replicated... |
11459496 | Strong supramolecular-based magnetic exchange in pi-stacked radicals. Structure and magnetism of a hydrogen-bonded verdazyl radical:hydroquinone molecular solid. | The X-ray crystal structure and magnetic properties of a molecular crystal consisting of 1,5-dimethyl-3-(2-pyridyl)-6-oxoverdazyl radical and hydroquinone (pyvd:hq) are presented. The structure contains a two-dimensional network of hydrogen bonds involving the hydroquinones and the pyridine ring of the pyvd radical. Th... |
11459474 | Self-encapsulation of poly-2,7-fluorenes in a dendrimer matrix. | The synthesis and characterization of complex dendritic, rigid rod poly-2,7-fluorene homopolymers and copolymers via a macromonomer approach is reported. Several 2,7-dibromofluorene monomers containing benzyl ether dendrons (generations 1, 2, and 3) in the 9,9'-position of the fluorene ring were prepared and employed i... |
11459654 | Macrocyclization in the design of a conformationally constrained Grb2 SH2 domain inhibitor. | Grubbs' olefin metathesis reaction was utilized to prepare a macrocyclic variant of a linear Grb2 SH2 domain antagonist in an attempt to induce a beta-bend conformation known to be required for high affinity binding. In extracellular Grb2 SH2 domain binding assays, the macrocyclic analogue exhibited an approximate 100-... |
11459464 | Avidin-dendrimer-(1B4M-Gd)(254): a tumor-targeting therapeutic agent for gadolinium neutron capture therapy of intraperitoneal disseminated tumor which can be monitored by MRI. | Peritoneal carcinomatosis is a late stage in cancer progress, for which no effective therapeutic modality exists. Targeting therapeutic agents to disseminated lesions may be a promising modality for treating peritoneal carcinomatosis. Gadolinium ((157,155)Gd) is known to generate Auger and internal conversion electrons... |
11459450 | Enhancement of gene expression by polyamidoamine dendrimer conjugates with alpha-, beta-, and gamma-cyclodextrins. | To improve the transfection efficiency of nonviral vector, we synthesized the starburst polyamidoamine dendrimer conjugates with alpha-, beta-, and gamma-cyclodextrins (CDE conjugates), expecting the synergistic effect of dendrimer and cyclodextrins (CyDs). The (1)H NMR spectroscopic data indicated that alpha-, beta-, ... |
11458330 | Controlled and complete release of a model poorly water-soluble drug, prednisolone, from hydroxypropyl methylcellulose matrix tablets using (SBE)(7m)-beta-cyclodextrin as a solubilizing agent. | Sustained-release formulations such as hydroxypropyl methylcellulose (HPMC)-based hydrophilic matrix tablets of poorly water-soluble drugs often result in incomplete release because of the poor solubility and dissolution rate of the drug in the hydrophilic matrix. Sulfobutylether-beta-cyclodextrins ((SBE)(7M)-beta-CDs)... |
11456473 | Photoisomerization by hula-twist: a fundamental supramolecular photochemical reaction. | The volume-conserving hula-twist cis/trans isomerization process has been incorporated in a general scheme for photoisomerization of polyenes, applicable to small organic molecules as well as to protein-bound polyene chromophores. The main theme is that in solution the conventional one-bond-flip mechanism dominates, wh... |
11456085 | The inclusion compound of a new ionizable derivative of beta-cyclodextrin with ferrocenium drug. | A new beta-cyclodextrin (beta-CD) derivative, mono[6-deoxy-6-(2-butenedinitrile-2,3-dimercapto sodium salt)]-beta-CD (6-mnt-beta-CD), and its inclusion compound with a ferrocenium drug, have been prepared and characterized by IR, UV, 13C-NMR spectroscopy, and mass spectrometry, elemental analysis, thermogravimetry, and... |
11454338 | Synthesis and anticancer activity of novel chiral D-glucose derived bis-imidazoles and their analogs. | A series of novel D-glucose derived bis-imidazoles and their analogs, which possess potential in bioorganic and supramolecular chemistry, were designed and synthesized from methyl alpha-D-glucoside through protection, bis-bromination, N-alkylation and deprotection. All new compounds were characterized by HRMS, 1H, 13C ... |
11453661 | Association of MUC-1 and SPGL-1 with low-density microdomain in T-lymphocytes: a preliminary note. | Two mucin-type glycoproteins, MUC-1 and P-selectin glycoprotein ligand-1 (PSGL-1), and glycosphingolipids (GSLs), expressed in human T-cell line HUT78, were highly enriched in low-density buoyant fraction (termed "GEM"), together with CD45, Yes, Fyn, and lck(56). Enrichment of MUC-1, PSGL-1 and GSLs, together with thes... |
11452031 | Characterisation of the structure of ocr, the gene 0.3 protein of bacteriophage T7. | The product of gene 0.3 of bacteriophage T7, ocr, is a potent inhibitor of type I DNA restriction and modification enzymes. We have used biophysical methods to examine the mass, stability, shape and surface charge distribution of ocr. Ocr is a dimeric protein with hydrodynamic behaviour equivalent to a prolate ellipsoi... |
11452022 | Solution structure of a DNA duplex with a chiral alkyl phosphonate moiety. | The solution structures of two DNA decamers of sequence d(CCACCpxGGAAC).(GTTCCGGTGG) with a chiral alkyl phosphonate moiety (px) have been determined using NMR and restrained molecular dynamics simulations and compared with the solution structure of the unmodified duplex. The (1)H NMR spectra of two samples with pure s... |
11452008 | Alanine-scanning mutagenesis of Aspergillus gamma-tubulin yields diverse and novel phenotypes. | We have created 41 clustered charged-to-alanine scanning mutations of the mipA, gamma-tubulin, gene of Aspergillus nidulans and have created strains carrying these mutations by two-step gene replacement and by a new procedure, heterokaryon gene replacement. Most mutant alleles confer a wild-type phenotype, but others a... |
11451666 | RFI-641 inhibits entry of respiratory syncytial virus via interactions with fusion protein. | <h4>Background</h4>RFI-641, a small dendrimer-like compound, is a potent and selective inhibitor of respiratory syncytial virus (RSV), which is currently a clinical candidate for the treatment of upper and lower respiratory tract infections caused by RSV. RFI-641 inhibits RSV growth with an IC(50) value of 50 nM and pr... |
11448161 | The porcine endogenous retrovirus long terminal repeat contains a single nucleotide polymorphism that confers distinct differences in estrogen receptor binding affinity between PERV A and PERV B/C subtypes. | Porcine endogenous retroviruses (PERV) have been shown to have zoonotic potential, both in vitro and in vivo. Once integrated into the host cell genome activation of the proviral genes is ultimately dependent upon transactivation of the long terminal repeat (LTR). Currently there is no direct evidence of host cell tran... |
11448998 | The LD4 motif of paxillin regulates cell spreading and motility through an interaction with paxillin kinase linker (PKL). | The small GTPases of the Rho family are intimately involved in integrin-mediated changes in the actin cytoskeleton that accompany cell spreading and motility. The exact means by which the Rho family members elicit these changes is unclear. Here, we demonstrate that the interaction of paxillin via its LD4 motif with the... |
11448994 | Human Vam6p promotes lysosome clustering and fusion in vivo. | Regulated fusion of mammalian lysosomes is critical to their ability to acquire both internalized and biosynthetic materials. Here, we report the identification of a novel human protein, hVam6p, that promotes lysosome clustering and fusion in vivo. Although hVam6p exhibits homology to the Saccharomyces cerevisiae vacuo... |
11448991 | Nuclear pore complexes form immobile networks and have a very low turnover in live mammalian cells. | The nuclear pore complex (NPC) and its relationship to the nuclear envelope (NE) was characterized in living cells using POM121-green fluorescent protein (GFP) and GFP-Nup153, and GFP-lamin B1. No independent movement of single pore complexes was found within the plane of the NE in interphase. Only large arrays of NPCs... |
11448985 | Nuclear pore complexes: dynamics in unexpected places. | In vivo studies on the dynamics of the nuclear pore complex (NPC) in yeast suggested that NPCs are highly mobile in the nuclear envelope. However, new evidence indicates that in mammalian cells NPCs are stably attached to a flexible lamina framework, but a peripheral component can exchange rapidly with an intranuclear ... |
11448183 | Hierarchical self-assembly of chiral complementary hydrogen-bond networks in water: reconstitution of supramolecular membranes. | Spontaneous formation of complementary hydrogen-bond pairs and their hierarchical self-assembly (reconstitution) into chiral supramolecular membranes are achieved in water by mixing amphiphilic pairs of glutamate-derived melamine 6 and ammonium-derivatized azobenzene cyanuric acid 4. Electron microscopy is used to obse... |
11448687 | X-ray structure of beta-cyclodextrin-2,7-dihydroxy-naphthalene.4.6 H(2)O: an unusually distorted macrocycle. | The inclusion complex beta-cyclodextrin.2,7-dihydroxynaphthalene.4.6 H(2)O crystallized in the monoclinic space group P2(1), with a=14.082(3), b=19.079(4), c=12.417(3) A, beta=109.28(3) degrees, V=3149.0(11) A(3), and Z=2. An X-ray study performed at room temperature shows that the crystal packing is of the herringbone... |
11448675 | The crystal structure of the 1:1 inclusion complex of beta-cyclodextrin with squaric acid. | The crystal and molecular structure of the 1:1 inclusion complex of beta-cyclodextrin (cyclomaltoheptaose) with squaric acid (3,4-dihydroxycyclobutene-1,2-dione) was determined by X-ray diffraction. The complex crystallizes in the monoclinic P2(1) space group and belongs to the monomeric cage-type, characterized by a h... |
11448673 | Chemoenzymatic synthesis of 2-chloro-4-nitrophenyl beta-maltoheptaoside acceptor-products using glycogen phosphorylase b. | In the present work, we aimed at developing a chemoenzymatic procedure for the synthesis of beta-maltooligosaccharide glycosides. The primer in the enzymatic reaction was 2-chloro-4-nitrophenyl beta-maltoheptaoside (G(7)-CNP), synthesised from beta-cyclodextrin using a convenient chemical method. CNP-maltooligosacchari... |
11447108 | Adenylyl cyclase Rv1625c of Mycobacterium tuberculosis: a progenitor of mammalian adenylyl cyclases. | The gene Rv1625c from Mycobacterium tuberculosis encodes a membrane-anchored adenylyl cyclase corresponding to exactly one-half of a mammalian adenylyl cyclase. An engineered, soluble form of Rv1625c was expressed in Escherichia coli. It formed a homodimeric cyclase with two catalytic centers. Amino acid mutations pred... |
11447103 | State transitions reveal the dynamics and flexibility of the photosynthetic apparatus. | The chloroplast-based photosynthetic apparatus of plants and algae associates various redox cofactors and pigments with approximately 70 polypeptides to form five major transmembrane protein complexes. Among these are two photosystems that have distinct light absorption properties but work in series to produce reducing... |
11442407 | Synthesis of a polymerizable metal-ion-chelating lipid for fluid bilayers. | Hydrated lipid structures, such as liposomes, that display tethered metal-ion-chelating groups have proven useful in peptide and protein binding, as well as 2D protein crystallization through molecular recognition of accessible histidine sites in proteins and peptides. Polymerizable metal-ion-chelating lipids bearing a... |
11442399 | Bis-8-hydroxyquinoline-armed diazatrithia-15-crown-5 and diazatrithia-16-crown-5 ligands: possible fluorophoric metal ion sensors. | The synthesis and preliminary photophysical properties of a series of diazatrithia-15-crown-5 and diazatrithia-16-crown-5 ligands containing two 8-hydroxyquinoline sidearms are reported. The ligands were prepared by a two-step process. First, diazatrithiacrown ethers 11 and 12 were prepared by treating bis(alpha-chloro... |
11440852 | Enzyme catalysis: a new definition accounting for noncovalent substrate- and product-like states. | Biological catalysis frequently causes changes in noncovalent bonding. By building on Pauling's assertion that any long-lived, chemically distinct interaction is a chemical bond, this article redefines enzyme catalysis as the facilitated making and/or breaking of chemical bonds, not just of covalent bonds. It is also a... |
11440567 | Thiadiazole-derived expanded heteroazaporphyrinoids. | [structure: see text] Heteroannulenes 1 and 3 containing three subunits of isoindole or pyrrole, respectively, three 1,3,4-thiadiazole moieties, and six aza-bridges have been synthesized by reaction of the corresponding diiminoisoindoline or diiminopyrroline with 2,5-diamino-1,3,4-thiadiazole. These conjugated nonaroma... |
11439053 | Formation of a phosphorus-phosphorus bond by successive one-electron reductions of a two-phosphinines-containing macrocycle: crystal structures, EPR, and DFT investigations. | Chemical and electrochemical reductions of the macrocycle 1 lead to the formation of a radical monoanion anion [1](*)(-) whose structure has been studied by EPR in liquid and frozen solutions. In accord with experimental (31)P hyperfine tensors, DFT calculations indicate that, in this species, the unpaired electron is ... |
11439043 | Molecular structures and magnetic resonance spectroscopic investigations of highly distorted six-coordinate low-spin iron(III) porphyrinate complexes. | Three bis-axially ligated complexes of iron(III) octaethyltetraphenylporphyrin, (OETPP)Fe(III), have been prepared, which are low-spin complexes, each with two axial nitrogen-donor ligands (N-methylimidazole (N-MeIm), 4-(dimethylamino)pyridine (4-NMe(2)Py), and 2-methylimidazole (2-MeImH)). The crystal and molecular st... |
11439099 | Polyamines regulate gap junction communication in connexin 43-expressing cells. | The control of cell-cell communication through gap junctions is thought to be crucial in normal tissue function and during various stages of tumorigenesis. However, few natural regulators of gap junctions have been found. We show here that increasing the activity of ornithine decarboxylase, or adding polyamines to the ... |
11438425 | Complexation of phenytoin with some hydrophilic cyclodextrins: effect on aqueous solubility, dissolution rate, and anticonvulsant activity in mice. | The main objective of this study was to evaluate the influence of hydroxypropylated beta- and gamma-cyclodextrins and Me-beta-cyclodextrin (HP-beta-CD, HP-gamma-CD, and Me-beta-CD, respectively) on the dissolution rate and bioavailability of the antiepileptic agent, phenytoin (DPH). The corresponding solid complexes we... |
11437357 | Molecular recognition in the p450cam monooxygenase system: direct monitoring of protein-protein interactions by using optical biosensor. | A real-time optical biosensor study on the interactions between putidaredoxin reductase (PdR), putidaredoxin (Pd), and cytochrome P450cam (P450cam) within the P450cam system was conducted. The binary Pd/P450cam and Pd/PdR complexes were revealed and kinetically characterized. The dominant role of electrostatic interact... |
11435171 | Molecular recognition in thylakoid structure and function. | In photosynthesis, light-harvesting chlorophyll molecules are shunted between photosystems by phosphorylation of the protein to which they are bound. An anchor for the phosphorylated chlorophyll-protein complex has now been identified in the reaction centre of chloroplast photosystem I. This finding supports the idea t... |
11434766 | Solution structure of the squash trypsin inhibitor MCoTI-II. A new family for cyclic knottins. | The "knottin" fold is a stable cysteine-rich scaffold, in which one disulfide crosses the macrocycle made by two other disulfides and the connecting backbone segments. This scaffold is found in several protein families with no evolutionary relationships. In the past few years, several homologous peptides from the Rubia... |
11433211 | Why Congo red binding is specific for amyloid proteins - model studies and a computer analysis approach. | <h4>Background</h4>The complexing of Congo red in two different ligand forms - unimolecular and supramolecular (seven molecules in a micelle) - with eight deca-peptides organized in a b-sheet was tested by computational analysis to identify its dye-binding preferences. Polyphenylananine and polylysine peptides were sel... |
11432993 | Effects of membrane cholesterol manipulation on excitation-contraction coupling in skeletal muscle of the toad. | 1. Single mechanically skinned fibres and intact bundles of fibres from the twitch region of the iliofibularis muscle of cane toads were used to investigate the effects of membrane cholesterol manipulation on excitation-contraction (E-C) coupling. The cholesterol content of membranes was manipulated with methyl-beta-cy... |
11432962 | Disruption of one intra-chain disulphide bond in the carboxyl-terminal propeptide of the proalpha1(I) chain of type I procollagen permits slow assembly and secretion of overmodified, but stable procollagen trimers and results in mild osteogenesis imperfecta. | Type I procollagen is a heterotrimer comprised of two proalpha1(I) chains and one proalpha2(I) chain. Chain recognition, association, and alignment of proalpha chains into correct registration are thought to occur through interactions between the C-terminal propeptide domains of the three chains. The C-propeptide of ea... |
11432824 | Lysine 188 substitutions convert the pattern of proteasome activation by REGgamma to that of REGs alpha and beta. | 11S REGs (PA28s) are multimeric rings that bind proteasomes and stimulate peptide hydrolysis. Whereas REGalpha activates proteasomal hydrolysis of peptides with hydrophobic, acidic or basic residues in the P1 position, REGgamma only activates cleavage after basic residues. We have isolated REGgamma mutants capable of a... |
11432815 | Listeria pathogenesis and molecular virulence determinants. | The gram-positive bacterium Listeria monocytogenes is the causative agent of listeriosis, a highly fatal opportunistic foodborne infection. Pregnant women, neonates, the elderly, and debilitated or immunocompromised patients in general are predominantly affected, although the disease can also develop in normal individu... |
11432808 | Biology of Giardia lamblia. | Giardia lamblia is a common cause of diarrhea in humans and other mammals throughout the world. It can be distinguished from other Giardia species by light or electron microscopy. The two major genotypes of G. lamblia that infect humans are so different genetically and biologically that they may warrant separate specie... |
11431325 | Dynamic micro-magnetic resonance imaging of liver micrometastasis in mice with a novel liver macromolecular magnetic resonance contrast agent DAB-Am64-(1B4M-Gd)(64). | DAB-Am64-(1B4M-Gd)(64) is a newly synthesized macromolecular liver magnetic resonance imaging (MRI) contrast agent with a polypropylenimine diaminobutane (DAB) dendrimer conjugated with a bifunctional diethylenetriaminepentaacetic acid (DTPA) derivative for complexing Gd(III) atoms. The characteristics of DAB-Am64-(1B4... |
11429419 | ACP Best Practice No 165: front line tests for the investigation of suspected porphyria. | The porphyrias are uncommon disorders of haem biosynthesis and their effective management requires prompt and accurate diagnosis. This article describes methods for the determination of urinary porphobilinogen, urinary and faecal total porphyrins, and total porphyrins in erythrocytes and plasma that are suitable for us... |
11428676 | Preparation and in vivo evaluation of parenteral metoclopramide-loaded poly(alkylcyanoacrylate) nanospheres in rats. | Metoclopramide-loaded poly(alkylcyanoacrylate) (PACA) nanospheres were prepared by emulsifier-free polymerization in aqueous media at ambient conditions. The optimum polymerization conditions for metoclopramide sorption on PACA nanospheres in the presence of dextran (DEX) or hydroxypropyl-beta-cyclodextran (HPCD) in th... |
11427271 | Three double-blind, randomized trials evaluating the safety and tolerance of different formulations of the saponin adjuvant QS-21. | The effects of the adjuvant QS-21 in various formulations on immediate pain on injection after intramuscular injection were evaluated in three Phase I clinical trials in healthy adults. Each trial was designed as a double-blind, randomized, four-way or five-way cross-over study with each subject acting as his/her own c... |
11427065 | Chemistry on surface-confined molecules: an approach to anchor isolated functional units to surfaces. | The synthesis of surface-confined, nanometer-sized dendrimers and Au nanoparticles was performed starting from single Pd(II) pincer adsorbate molecules (10) embedded as isolated species into 11-mercapto-1-undecanol and decanethiol self-assembled monolayers (SAMs) on gold. The coordination of monolayer-protected Au nano... |
11427049 | An enthalpic component in cooperativity: the relationship between enthalpy, entropy, and noncovalent structure in weak associations. | Attempts to quantify binding interactions of noncovalent complexes in aqueous solution have been stymied by complications arising from enthalpy-entropy compensation and cooperativity. We have extended work detailing the relationship between noncovalent structure and free energy of binding to include the roles of enthal... |
11427048 | Computing handedness: quantized and superposed switch and dynamic memory of helical polysilylene. | Two new conjugating helical polymers comprising a rodlike silicon backbone and enantiopure chiral pendants, poly[(R)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-1) and its diastereomeric poly[(S)-3,7-dimethyloctyl-(S)-3-methylpentylsilylene] (PS-2), were prepared. Molecular mechanics calculations of PS-1 and PS-2... |
11427410 | Celiac disease-associated autoimmune endocrinopathies. | Celiac disease (CD) is an autoimmune disorder induced by gluten intake in genetically susceptible individuals. It is characterized by the presence of serum antibodies to endomysium, reticulin, gliadin, and tissue transglutaminase. The incidence of CD in various autoimmune disorders is increased 10- to 30-fold in compar... |
11425829 | Embryotoxicity of magainin-2-amide and its enhancement by cyclodextrin, albumin, hydrogen peroxide and acidification. | <h4>Background</h4>The channel-forming antimicrobial peptide, magainin-2-amide, interacts preferentially with negatively charged, non cholesterol-containing membranes, including those of sperm, oocytes and cells of pre-implantation embryos. Cyclodextrin and albumin remove membrane cholesterol and together with hydrogen... |
11425548 | Synthesis and nuclease stability of trilysyl dendrimer-oligodeoxyribonucleotide hybrids. | Hybrids of oligonucleotides and trilysyl-dendrimers with terminal acyl groups were prepared via solid-phase synthesis, including a DNA hexamer bearing an additional 3'-appendage. These were shown to be degraded more slowly by nuclease S1 than control strands, particularly at low pH, and, in one case, to form a duplex w... |
11424215 | Isolation and characterization of sea urchin egg lipid rafts and their possible function during fertilization. | Specialized membrane microdomains called rafts are thought to play a role in many types of cell-cell interactions and signaling. We have investigated the possibility that sea urchin eggs contain these specialized membrane microdomains and if they play a role in signal transduction at fertilization. A low density, TX-10... |
11421643 | Possible role of juxtaglomerular apparatus in low cardiac output syndrome and multiple organ failure: modulation by high sodium load. | Sympathetic overdrive in acute low cardiac output syndrome, diverts blood from cutaneous and visceral circulation centripetally. Microcirculation in general, and renal circulation in particular, deteriorates during these circulatory adjustments leading to multi-organ failure (MOF). Decreased afferent glomerular arterio... |
11421704 | Syntheses, structures, and physicochemical properties of diruthenium compounds of tetrachlorocatecholate with metal-metal bonded Ru(3+)(mu-OR)(2)Ru(3+) and Ru(3.5+)(mu-OR)(2)Ru(3.5+) cores (R = CH(3) and C(2)H(5)). | Metal-metal bonded Ru(3+)(mu-OR)(2)Ru(3+) and Ru(3.5+)(mu-OR)(2)Ru(3.5+) (R = CH(3) and CH(3)CH(2)) compounds with tetrachlorocatecholate (Cl(4)Cat) have been synthesized in the corresponding alcohol, MeOH and EtOH, from a nonbridged Ru(2+)-Ru(3+) compound, Na(3)[Ru(2)(Cl(4)Cat)(4)(THF)].3H(2)O.7THF (1). In alcohol sol... |
11421698 | Metal-capped alpha-cyclodextrins: squaring the circle. | This report describes the four-step synthesis of 6A,6D-diamino-6A,6D-dideoxy-2(A),2(B),2(C),2(D),2(E),2(F),3(A),3(B),3(C),3(D),3(E),3(F), 6(B),6(C),6(E),6(F)-hexadeca-O-methylcyclomaltohexaose (5), a methylated alpha-CD that bears two -CH(2)NH(2) ligands located on diametrically opposed glucopyranose rings. Reaction of... |
11421685 | Self-assembly of a porphyrin array via the molecular recognition approach: synthesis and properties of a cyclic zinc(II) porphyrin trimer based on coordination and hydrogen bonding. | Self-assembly of [5-(pyrazol-4-yl)-10,20-bis(p-tolyl)-15- (2-ethoxycarbonylphenyl)porphyrinato]-zinc(II) (1), designed to have both a coordination site and a hydrogen bonding site, leads to a stable cyclic trimer array where coordination of the pyrazole nitrogen to the zinc(II) ion as well as hydrogen bonding between c... |
11421684 | Coordination trends in alkali metal crown ether uranyl halide complexes: the series [A(crown)]2[UO(2)X(4)] where A=Li, Na, K and X=Cl, Br. | UO(2)(C(2)H(3)O(2))(2).2H(2)O reacts with AX or A(C(2)H(3)O(2) or ClO(4)) (where A = Li, Na, K; X = Cl, Br) and crown ethers in HCl or HBr aqueous solutions to give the sandwich-type compounds [K(18-crown-6)](2)[UO(2)Cl(4)] (1), [K(18-crown-6)](2)[UO(2)Br(4)] (2), [Na(15-crown-5)](2)[UO(2)Cl(4)] (3), [Na(15-crown-5)](2... |
11423440 | HIV-1 capsid protein forms spherical (immature-like) and tubular (mature-like) particles in vitro: structure switching by pH-induced conformational changes. | The viral genome and replicative enzymes of the human immunodeficiency virus are encased in a shell consisting of assembled mature capsid protein (CA). The core shell is a stable, effective protective barrier, but is also poised for dissolution on cue to allow transmission of the viral genome into its new host. In this... |
11423436 | Domain formation in models of the renal brush border membrane outer leaflet. | The plasma membrane outer leaflet plays a key role in determining the existence of rafts and detergent-resistant membrane domains. Monolayers with lipid composition mimicking that of the outer leaflet of renal brush border membranes (BBM) have been deposited on mica and studied by atomic force microscopy. Sphingomyelin... |
11423435 | Fluorescence lifetime heterogeneity in aggregates of LHCII revealed by time-resolved microscopy. | Two-photon excitation, time-resolved fluorescence microscopy was used to investigate the fluorescence quenching mechanisms in aggregates of light-harvesting chlorophyll a/b pigment protein complexes of photosystem II from green plants (LHCII). Time-gated microscopy images show the presence of large heterogeneity in flu... |
11423431 | Structure and hydration of the DNA-human topoisomerase I covalent complex. | The structure and hydration of reconstituted human topoisomerase I comprising the core and the carboxyl-terminal domains in covalent complex with 22-basepair DNA duplex has been investigated by molecular dynamics simulation. The structure and the intermolecular interactions were found to be well maintained over the sim... |
11423420 | Conformations of an adenine bulge in a DNA octamer and its influence on DNA structure from molecular dynamics simulations. | Molecular dynamics simulations have been applied to the DNA octamer d(GCGCA-GAAC). d(GTTCGCGC), which has an adenine bulge at the center to determine the pathway for interconversion between the stacked and extended forms. These forms are known to be important in the molecular recognition of bulges. From a total of ~35 ... |
11423412 | Reconstituted syntaxin1a/SNAP25 interacts with negatively charged lipids as measured by lateral diffusion in planar supported bilayers. | According to the soluble N-ethylmaleimide-sensitive factor (NSF)-attachment protein (SNAP) receptor hypothesis (SNARE hypothesis), interactions between target SNAREs and vesicle SNAREs (t- and v-SNAREs) are required for membrane fusion in intracellular vesicle transport and exocytosis. The precise role of the SNAREs in... |
11423403 | Interaction of lung surfactant proteins with anionic phospholipids. | Langmuir isotherms, fluorescence microscopy, and atomic force microscopy were used to study lung surfactant specific proteins SP-B and SP-C in monolayers of dipalmitoylphosphatidylglycerol (DPPG) and palmitoyloleoylphosphatidylglycerol (POPG), which are representative of the anionic lipids in native and replacement lun... |
11423396 | Interaction of SNX482 with domains III and IV inhibits activation gating of alpha(1E) (Ca(V)2.3) calcium channels. | We have investigated the action of SNX482, a toxin isolated from the venom of the tarantula Hysterocrates gigas, on voltage-dependent calcium channels expressed in tsa-201 cells. Upon application of 200 nM SNX482, R-type alpha(1E) calcium channels underwent rapid and complete inhibition, which was only poorly reversibl... |
11420447 | Increasing protein stability using a rational approach combining sequence homology and structural alignment: Stabilizing the WW domain. | This study shows that a combination of sequence homology and structural information can be used to increase the stability of the WW domain by 2.5 kcal mol(-1) and increase the T(m) by 28 degrees C. Previous homology-based protein design efforts typically investigate positions with low sequence identity, whereas this st... |
11420439 | Mass spectrometric study of the Escherichia coli repressor proteins, Ic1R and Gc1R, and their complexes with DNA. | In Escherichia coli, the IclR protein regulates both the aceBAK operon and its own synthesis. Database homology searches have identified many IclR-like proteins, now known as the IclR family, which can be identified by a conserved C-terminal region. We have cloned and purified one of these proteins, which we have named... |
11418569 | The Bordetella bhu locus is required for heme iron utilization. | Bordetella pertussis and Bordetella bronchiseptica are capable of obtaining iron from hemin and hemoglobin. Genes encoding a putative bacterial heme iron acquisition system (bhu, for Bordetella heme utilization) were identified in a B. pertussis genomic sequence database, and the corresponding DNA was isolated from a v... |
11418515 | In vitro comparison of the antimycotic activity of a miconazole-HP-beta-cyclodextrin solution with a miconazole surfactant solution. | The antimycotic activity of a new parenteral solution containing miconazole was compared with that of a marketed solution (Daktarin IV solution). This solution has been withdrawn from the Belgian market, probably because of toxic effects related to the presence of polyoxyl 35 castor oil. We propose a new formulation co... |
11416127 | PLIP, a novel splice variant of Tip60, interacts with group IV cytosolic phospholipase A(2), induces apoptosis, and potentiates prostaglandin production. | The group IV cytosolic phospholipase A(2) (cPLA(2)) has been localized to the nucleus (M. R. Sierra-Honigmann, J. R. Bradley, and J. S. Pober, Lab. Investig. 74:684-695, 1996) and is known to translocate from the cytosolic compartment to the nuclear membrane (S. Glover, M. S. de Carvalho, T. Bayburt, M. Jonas, E. Chi, ... |
11415464 | Haem disorder in recombinant- and reticulocyte-derived haemoglobins: evidence for stereoselective haem insertion in eukaryotes. | We have used NMR spectroscopy to measure haem disorder in adult human haemoglobin (HbA) obtained from mature erythrocyte cells and from yeast expressing recombinant HbA. Reticulocyte-derived HbA contained much higher levels of haem disorder (11% alpha- and 28% beta-subunit disorder) than observed for HbA from mature er... |
11415430 | Cholesterol depletion reduces apical transport capacity in epithelial Madin-Darby canine kidney cells. | Reduction of the cholesterol level in membranes of epithelial Madin-Darby canine kidney (MDCK) cells reverses the apical-to-basolateral transport ratio of the apical membrane marker protein influenza virus haemagglutinin and the secreted glycoprotein gp80. At the same time, basolateral transport of the vesicular stomat... |
11415429 | Functional role of polar amino acid residues in Na+/H+ exchangers. | Na(+)/H(+) exchangers are a family of ubiquitous membrane proteins. In higher eukaryotes they regulate cytosolic pH by removing an intracellular H(+) in exchange for an extracellular Na(+). In yeast and Escherichia coli, Na(+)/H(+) exchangers function in the opposite direction to remove intracellular Na(+) in exchange ... |
11412948 | Electronic control of helical chirality. | Chiral phenomena are common in living systems. Despite the fact that development of materials has often been inspired by chemistry from the biological world, materials that take advantage of inherent chirality have found relatively few applications. It is therefore probable that much remains to be gained from novel app... |
11413332 | Biologic studies of chimeras of highly and moderately virulent molecular clones of simian immunodeficiency virus SIVsmPBj suggest a critical role for envelope in acute AIDS virus pathogenesis. | Previous studies identified three molecular clones of the acutely pathogenic SIVsmPBj strain that varied in terms of relative in vivo pathogenicity. One clone, SIVsmPBj6.6, reproducibly induced a rapidly fatal disease in pigtailed macaques. In contrast, a highly related clone (SIVsmPBj6.9) was only minimally pathogenic... |
11413330 | A monoclonal antibody specific for reovirus outer-capsid protein sigma3 inhibits sigma1-mediated hemagglutination by steric hindrance. | Reovirus virions are nonenveloped icosahedral particles consisting of two concentric protein shells, termed outer capsid and core. Outer-capsid protein sigma1 is the viral attachment protein and binds carbohydrate molecules on the surface of host cells. Monoclonal antibody (MAb) 4F2, which is specific for outer-capsid ... |
11413297 | A single amino acid alteration in the human parainfluenza virus type 3 hemagglutinin-neuraminidase glycoprotein confers resistance to the inhibitory effects of zanamivir on receptor binding and neuraminidase activity. | Entry and fusion of human parainfluenza virus type 3 (HPF3) requires interaction of the viral hemagglutinin-neuraminidase (HN) glycoprotein with its sialic acid receptor. 4-Guanidino-2,4-dideoxy-2,3-dehydro-N-acetylneuraminic acid (4-GU-DANA; zanamivir), a sialic acid transition-state analog designed to fit the influen... |
11413293 | Common antiviral cytotoxic t-lymphocyte epitope for diverse arenaviruses. | Members of the Arenaviridae family have been isolated from mammalian hosts in disparate geographic locations, leading to their grouping as Old World types (i.e., lymphocytic choriomeningitis virus [LCMV], Lassa fever virus [LFV], Mopeia virus, and Mobala virus) and New World types (i.e., Junin, Machupo, Tacaribe, and S... |
11412035 | EGF-dependent translocation of green fluorescent protein-tagged PLC-gamma1 to the plasma membrane and endosomes. | Growth factor-dependent translocation of phospholipase C-gamma1 (PLC-gamma1) was investigated using a green fluorescent protein-tagged PLC-gamma1 (PLC-gamma1-GFP) expressed in human epidermoid carcinoma A-431 cells. In the absence of growth factors, PLC-gamma1-GFP was present throughout the cytoplasm of A-431 cells. Tr... |
11410931 | The ubiquitin-proteasome pathway and proteasome inhibitors. | The ubiquitin-proteasome pathway has emerged as a central player in the regulation of several diverse cellular processes. Here, we describe the important components of this complex biochemical machinery as well as several important cellular substrates targeted by this pathway and examples of human diseases resulting fr... |
11408216 | Novel bifunctional inhibitor of xylanase and aspartic protease: implications for inhibition of fungal growth. | A novel bifunctional inhibitor (ATBI) from an extremophilic Bacillus sp. exhibiting an activity against phytopathogenic fungi, including Alternaria, Aspergillus, Curvularia, Colletotricum, Fusarium, and Phomopsis species, and the saprophytic fungus Trichoderma sp. has been investigated. The 50% inhibitory concentration... |
11404031 | Inclusion complex of piroxicam with beta-cyclodextrin and incorporation in cationic microemulsion. In vitro drug release and in vivo topical anti-inflammatory effect. | Topical formulations of piroxicam were evaluated by determination of their in vitro release and in vivo anti-inflammatory effect. The in vitro release assay demonstrated that the microemulsion (ME) systems provided a reservoir effect for piroxicam release. However, the incorporation of the ME into carboxyvinilic gel pr... |
11395465 | Global versus local regulatory roles for Lrp-related proteins: Haemophilus influenzae as a case study. | Lrp (leucine-responsive regulatory protein) plays a global regulatory role in Escherichia coli, affecting expression of dozens of operons. Numerous lrp-related genes have been identified in different bacteria and archaea, including asnC, an E. coli gene that was the first reported member of this family. Pairwise compar... |
11395445 | Autoregulation of the dnaA-dnaN operon and effects of DnaA protein levels on replication initiation in Bacillus subtilis. | In Escherichia coli, the DnaA protein level appears to play a pivotal role in determining the timing of replication initiation. To examine the effects on replication initiation in B. subtilis, we constructed a strain in which a copy of the dnaA gene was integrated at the purA locus on the chromosome under the control o... |
11390575 | Initiation of minute virus of mice DNA replication is regulated at the level of origin unwinding by atypical protein kinase C phosphorylation of NS1. | Minute virus of mice nonstructural protein NS1 is a multifunctional protein that is involved in many processes necessary for virus propagation. To perform its distinct activities in timely coordinated manner, NS1 was suggested to be regulated by posttranslational modifications, in particular phosphorylation. In fact, N... |
11389875 | Modulation by cellular cholesterol of gene transcription via the cyclic AMP response element. | The effect of rapid changes in cellular cholesterol content on adenosine 3',5'-cyclic monophosphate (cAMP) response element-mediated gene transcription was investigated. The study was carried out in Chinese hamster ovary (CHO-K1) cells permanently expressing the human beta(2)-adrenoceptor. Gene transcription was quanti... |
11375757 | Macrocycles mimic the extended peptide conformation recognized by aspartic, serine, cysteine and metallo proteases. | It has been previously demonstrated that aspartic, serine, metallo and cysteine proteases bind to their inhibitors and substrate analogues in a single conformation, the saw-tooth or extended beta-strand. Consequently a generic approach to the development of protease inhibitors is the use of constraints that conformatio... |
11343278 | Chemical synthesis of cross-linked poly(KGGVG), an elastin-like biopolymer. | Previous studies afforded on peptides and polypeptides containing repetitive sequences of elastin have largely demonstrated that their molecular and supramolecular properties are fully representative of those of tropoelastin, the soluble, linear precursor of elastin itself. In the attempt to synthesize cross-linked ela... |
11427733 | Reversible encapsulation by self-assembling resorcinarene subunits. | Encapsulation complexes are assemblies in which a reversibly formed host more or less completely surrounds guest molecules. Host structures held together by hydrogen bonds have lifetimes in organic solvents of milliseconds to hours, long enough to directly observe the encapsulated guest by NMR spectroscopy. We describe... |
11427715 | Binding and disruption of phospholipid bilayers by supramolecular RNA complexes. | In an RNA world, RNAs would have regulated traffic through normally impermeable bilayer membranes. Using selection-amplification we previously found RNAs that bind stably and increase the ionic conductance of phospholipid membranes at high Mg(2+) and Ca(2+) concentrations. Now selection in reduced divalents yields RNAs... |
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