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12614610 | Chromatin fiber folding: requirement for the histone H4 N-terminal tail. | We have developed a self-assembly system for nucleosome arrays in which recombinant, post-translationally unmodified histone proteins are combined with DNA of defined-sequence to form chromatin higher-order structure. The nucleosome arrays obtained are highly homogeneous and sediment at 53S when maximally folded in 1mM... |
12615391 | DNA extraction using bacterial magnetic particles modified with hyperbranched polyamidoamine dendrimer. | A cascading hyperbranched polyamidoamine dendrimer was synthesized on the surface of bacterial magnetite from Magnetospirillum magneticum AMB-1 to allow enhanced extraction of DNA from fluid suspensions. Characterization of the synthesis revealed linear doubling of the surface amine charge from generations one through ... |
12615410 | Influence of methyl-beta-cyclodextrin and liposomes on rheological properties of Carbopol 974P NF gels. | The influence of positively-charged and sterically stabilized liposomes and/or methyl-beta-cyclodextrin on rheological properties of Carbopol 974P NF hydrogels was investigated. All formulations have displayed a shear-thinning behavior of Carbopol gels, and the rate stress as a function of the shear rate was fitted usi... |
12615406 | The interaction of cationic dendrons with albumin and their diffusion through cellulose membranes. | Amphipathic dendrons (partial dendrimers) having three lipidic (C(14)) chains coupled to dendritic lysine head groups with 8, 16 or 32 free terminal amino groups have been synthesised by solid phase peptide synthesis. Their interaction with albumin was studied in the presence of NaCl using dynamic dialysis, the diffusi... |
12615402 | Dendriplexes and their characterisation. | The interaction of DNA with partial dendrimers (dendritic polylysine containing seven lysines and eight terminal amino groups with or without a lipidic core) was studied. Compact complexes were formed which we term "dendriplexes". Agarose gel electrophoresis and exclusion of ethidium bromide confirmed the interaction. ... |
12614848 | Caspase activation is accelerated by the inhibition of arsenite-induced, membrane rafts-dependent Akt activation. | Renewed interest in arsenic has been shown recently due to its dual nature of being a potent toxin and a drug for treatment of acute promyelocytic leukemia (APL) because of its ability to trigger caspase activation. Here, we found that sodium arsenite (NaAsO(2)) also triggers the signal for activation of Akt and downst... |
12616627 | Polyglycine II nanosheets: supramolecular antivirals? | Tetraantennary peptides [glycine(n)-NHCH(2)](4)C can form stable noncovalent structures by self-assembly through intermolecular hydrogen bonding. The oligopeptide chains assemble as polyglycine II to yield submicron-sized, flat, one-molecule-thick sheets. Attachment of alpha-N-acetylneuraminic acid (Neu5Acalpha) to the... |
12616548 | Organic templates for the generation of inorganic materials. | Mankind's fascination with shapes and patterns, many examples of which come from nature, has greatly influenced areas such as art and architecture. Science too has long since been interested in the origin of shapes and structures found in nature. Whereas organic chemistry in general, and supramolecular chemistry especi... |
12611545 | Stability of divalent europium in an ionic liquid: spectroscopic investigations in 1-methyl-3-butylimidazolium hexafluorophosphate. | In this work, devoted to 1-methyl-3-butylimidazolium hexafluorophosphate ionic liquid (BumimPF(6)), the importance of the purity of the solvent for spectroscopic investigations is highlighted. Results from small angle X-ray scattering indicate that the pure solvent exhibits a local organization. Europium(II), which app... |
12611534 | Electronic structure of iron chlorins: characterization of bis(l-valine methyl ester)(meso-tetraphenylchlorin)iron(III)triflate and bis(l-valine methyl ester)(meso-tetraphenylchlorin)iron(II). | The synthesis and characterization of the two iron chlorin complexes [Fe(III)(TPC)(NH(2)CH(CO(2)CH(3))(CH(CH(3))(2)))(2)]CF(3)SO(3) (1) and Fe(II)(TPC)[(NH(2)CH(CO(2)CH(3))(CH(CH(3))(2))](2) (2) are reported. The crystal structure of complex 1 has been determined. The X-ray structure shows that the porphyrinate rings a... |
12611533 | Assembly of discrete, one-, two-, and three-dimensional silver(I) supramolecular complexes containing encapsulated acetylide dianion with nitrogen-donor spacers. | The first successful attempt to construct supramolecular entities via incorporation of bifunctional exodentate ligands into the silver acetylide system is reported. Coordination assembly with nitrogen-donor spacers led to the formation of five distinct supramolecular complexes, namely [(Ag(2)C(2))(AgCF(3)CO(2))(4)(pyz)... |
12611531 | Substantial increase of the ordering temperature for [MnII/MoIII(CN)7]-based magnets as a function of the 3d ion site geometry: example of two supramolecular materials with Tc = 75 and 106 K. | Two molecule-based magnets, [Mn(2)(tea)Mo(CN)(7)].H(2)O, 1, and [Mn(2)(tea)Mo(CN)(7)], 2 (tea stands for triethanolamine), formed with the 4d ion building block, [Mo(CN)(7)](4)(-), Mn(II) ions, and an additional ligand, tea, have been prepared and structurally characterized by single-crystal X-ray analyses. Whereas 1 i... |
12611505 | High-nuclearity metal-cyanide clusters: synthesis, magnetic properties, and inclusion behavior of open-cage species incorporating [(tach)M(CN)3] (M = Cr, Fe, Co) complexes. | The use of 1,3,5-triaminocyclohexane (tach) as a capping ligand in generating metal-cyanide cage clusters with accessible cavities is demonstrated. The precursor complexes [(tach)M(CN)(3)] (M = Cr, Fe, Co) are synthesized by methods similar to those employed in preparing the analogous 1,4,7-triazacyclononane (tacn) com... |
12611503 | Anion receptors: a new class of amide/quaternized amine macrocycles and the chelate effect. | A new class of tetraamide macrocyclic receptors for anions with two quaternized amine functionalities exhibited higher affinities for anions compared with the corresponding neutral amides. In two crystal structures of halide complexes of the prototypes with phenyl and pyridine spacers, the anions are held by hydrogen b... |
12609631 | 1H NMR study of the inclusion of Costa-type organocobalt(III) complexes in cyclodextrins. | The inclusion behavior between Costa-type complexes and cyclodextrins (CDs) was studied by 1H NMR in aqueous solution. The results indicated that 1:1 inclusion complex was formed, in which the alkyl group of the guest was included in the cavity of CDs. The stability constants of the inclusion complexes were determined ... |
12609630 | Comparison of molecular orientation and phase transition behaviors in the two kinds of ordered ultrathin films of reversed duckweed polymer ES-3 studied by infrared grazing reflection-absorption spectroscopy. | A multilayer LB film and a casting film of reversed duckweed polymer ES-3 on Au-evaporated glass slides were investigated by Fourier Transform infrared grazing reflection-absorption spectroscopy. It is found that the two kinds of ordered ultrathin films have different orientation of alkyl chains, nearly perpendicular t... |
12609618 | Preparation and study on the solid inclusion complex of sparfloxacin with HP-beta-cyclodextrin. | The interaction of sparfloxacin with HP-beta-cyclodextrin (HP-beta-CD) has been studied by several analytical techniques, including 1H NMR, fluorescence spectroscopy, infrared spectroscopy, thermal analysis and scanning electron microscopy. In this paper, solid inclusion complex of sparfloxacin with HP-beta-CD was synt... |
12610164 | Effects of dipeptide insertions between codons 69 and 70 of human immunodeficiency virus type 1 reverse transcriptase on primer unblocking, deoxynucleoside triphosphate inhibition, and DNA chain elongation. | Finger insertion mutations of human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) (T69S mutations followed by various dipeptide insertions) have a multinucleoside resistance phenotype that can be explained by decreased sensitivity to deoxynucleoside triphosphate (dNTP) inhibition of the nucleotide-de... |
12610161 | Chimeric and pseudotyped parvoviruses minimize the contamination of recombinant stocks with replication-competent viruses and identify a DNA sequence that restricts parvovirus H-1 in mouse cells. | Recent studies demonstrated the ability of the recombinant autonomous parvoviruses MVMp (fibrotropic variant of the minute virus of mice) and H-1 to transduce therapeutic genes in tumor cells. However, recombinant vector stocks are contaminated by replication-competent viruses (RCVs) generated during the production pro... |
12610160 | Human papillomavirus types 16, 31, and 58 use different endocytosis pathways to enter cells. | The early steps of the intracellular trafficking of human papillomavirus type 16 (HPV-16), -31, and -58 pseudovirions were studied by investigating the effects of drugs acting at defined points of endocytosis pathways on virus-like particle-mediated pseudoinfection by overexpression of a dominant-negative form of the E... |
12610154 | T cells infiltrate the brain in murine and human transmissible spongiform encephalopathies. | CD4 and CD8 T lymphocytes infiltrate the parenchyma of mouse brains several weeks after intracerebral, intraperitoneal, or oral inoculation with the Chandler strain of mouse scrapie, a pattern not seen with inoculation of prion protein knockout (PrP(-/-)) mice. Associated with this cellular infiltration are expression ... |
12610135 | A zinc ion controls assembly and stability of the major capsid protein of rotavirus. | The recent determination of the crystal structure of VP6, the major capsid protein of rotavirus, revealed a trimer containing a central zinc ion coordinated by histidine 153 from each of the three subunits. The role of the zinc ion in the functions of VP6 was investigated by site-directed mutagenesis. The mutation of h... |
12610132 | Two nonoverlapping domains on the Norwalk virus open reading frame 3 (ORF3) protein are involved in the formation of the phosphorylated 35K protein and in ORF3-capsid protein interactions. | Expression of the Norwalk virus open reading frame 3 (ORF3) in Spodoptera frugiperda (Sf9) cells yields two major forms, the predicted 23,000-molecular-weight (23K) form and a larger 35K form. The 23K form is able to interact with the ORF2 capsid protein and be incorporated into virus-like particles. In this paper, we ... |
12610121 | A virus-virus interaction circumvents the virus receptor requirement for infection by pathogenic retroviruses. | During ongoing C-type retrovirus infection, the probability of leukemia caused by insertional gene activation is markedly increased by the emergence of recombinant retroviruses that repeatedly infect host cells. The murine mink cell focus-inducing (MCF) viruses with this property have acquired characteristic changes in... |
12608839 | Mild oxidation of alcohols with o-iodoxybenzoic acid (IBX) in water/acetone mixture in the presence of beta-cyclodextrin. | A mild and efficient oxidation of alcohols with o-iodoxybenzoic acid (IBX) catalyzed by beta-cyclodextrin in a water/acetone mixture (86:14) has been developed. A series of alcohols were oxidized at room temperature in excellent yields. |
12608827 | Highly efficient deprotection of aromatic acetals under neutral conditions using beta-cyclodextrin in water. | Aromatic acetals have been deprotected to the corresponding aldehydes under biomimetic conditions for the first time using beta-cyclodextrin in water under neutral conditions, thereby overcoming many of the drawbacks associated with earlier methodologies. This method, apart from being simple with regard to recycling of... |
12608807 | Synthesis and characterization of beta-trifluoromethyl-meso-tetraphenylporphyrins. | Beta-trifluoromethyl-meso-tetraphenylporphyrins were synthesized to investigate the electronic and steric effects of the trifluoromethyl groups on the macrocycle. Preparation of these novel porphyrins was carried out by copper-assisted trifluoromethylation of beta-tetrabromo-meso-tetraphenylporphyrin metal complexes an... |
12608788 | Conjugated macrocycles related to the porphyrins. 25. Proton NMR spectroscopic evidence for a preferred [18]annulene substructure in carbaporphyrins from the magnitude of selected 4J(H,H) CH=C-CH3 coupling constants. | Two new benzocarbaporphyrins with four or five alkyl substituents have been synthesized by the "3 + 1" MacDonald methodology. At lower temperatures, the proton NMR spectrum of the asymmetrically substituted carbaporphyrin 8 gave two NH resonances, while carbaporphyrin 9, which retains a plane of symmetry, gave only one... |
12608778 | 1H NMR studies of maltose, maltoheptaose, alpha-, beta-, and gamma-cyclodextrins, and complexes in aqueous solutions with hydroxy protons as structural probes. | The (1)H NMR chemical shifts, coupling constants, temperature coefficients, and exchange rates have been measured for the hydroxy protons of aqueous solutions of alpha-, beta-, and gamma-cyclodextrins, maltose, and maltoheptaose. In cyclodextrins (CDs), the high chemical shift of the O(3)H signal and its small (3)J(OH,... |
12609902 | Activation of hydrogen peroxide in horseradish peroxidase occurs within approximately 200 micro s observed by a new freeze-quench device. | To observe the formation process of compound I in horseradish peroxidase (HRP), we developed a new freeze-quench device with approximately 200 micro s of the mixing-to-freezing time interval and observed the reaction between HRP and hydrogen peroxide (H(2)O(2)). The developed device consists of a submillisecond solutio... |
12609901 | Stability and Cu(II) binding of prion protein variants related to inherited human prion diseases. | All inherited forms of human prion diseases are linked with mutations in the prion protein (PrP) gene. Here we have investigated the stability and Cu(II) binding properties of three recombinant variants of murine full-length PrP(23-231)-containing destabilizing point mutations that are associated with human Gerstmann-S... |
12609899 | Orientation and interactions of an essential tryptophan (Trp-38) in the capsid subunit of Pf3 filamentous virus. | The filamentous bacteriophage Pf3 consists of a covalently closed DNA single strand of 5833 nucleotides sheathed by approximately 2500 copies of a 44-residue capsid subunit. The capsid subunit contains a single tryptophan residue (Trp-38), which is located within the basic C-terminal sequence (-RWIKAQFF) and is essenti... |
12609898 | Monitoring of the formation and dissociation of polyethylenimine/DNA complexes by two photon fluorescence correlation spectroscopy. | Polyethylenimines (PEI) constitute efficient nonviral vectors for gene transfer. However, because free PEI shows some cytotoxicity and because intracellular dissociation of PEI/DNA complexes seems to be required for efficient transfection, it is important to monitor the concentrations of free and bound partners in the ... |
12609897 | Nanotubules formed by highly hydrophobic amphiphilic alpha-helical peptides and natural phospholipids. | We previously reported that the 18-mer amphiphilic alpha-helical peptide, Hel 13-5, consisting of 13 hydrophobic residues and five hydrophilic amino acid residues, can induce neutral liposomes (egg yolk phosphatidylcholine) to adopt long nanotubular structures and that the interaction of specific peptides with specific... |
12609890 | Short peptide amyloid organization: stabilities and conformations of the islet amyloid peptide NFGAIL. | Experimentally, short peptides have been shown to form amyloids similar to those of their parent proteins. Consequently, they present useful systems for studies of amyloid conformation. Here we simulate extensively the NFGAIL peptide, derived from the human islet amyloid polypeptide (residues 22-27). We simulate differ... |
12609888 | Thermodynamic characterization of the folding coupled DNA binding by the monomeric transcription activator GCN4 peptide. | Dimerization is a widely believed critical requirement for the yeast transcriptional activator GCN4 specifically recognizing its DNA target sites. Nonetheless, the binding of the monomeric GCN4 to DNA target sites AP-1 and ATF/CREB was recently detected by kinetic studies. Here, for the first time, we present a detaile... |
12609884 | Real-time analysis of the effects of cholesterol on lipid raft behavior using atomic force microscopy. | Cholesterol plays a crucial role in cell membranes, and has been implicated in the assembly and maintenance of sphingolipid-rich rafts. We have examined the cholesterol-dependence of model rafts (sphingomyelin-rich domains) in supported lipid monolayers and bilayers using atomic force microscopy. Sphingomyelin-rich dom... |
12609882 | A rhombohedral phase of lipid containing a membrane fusion intermediate structure. | We constructed the electron density distribution from the x-ray diffraction of a phase of phospholipid that exhibited rhombohedral symmetry. To determine the phases of the diffraction amplitudes, we first extended the well-known one-dimensional swelling method for planar bilayers to a three-dimensional method applicabl... |
12609873 | Control of ion conduction in L-type Ca2+ channels by the concerted action of S5-6 regions. | Voltage-gated L-type Ca(2+) channels from cardiac (alpha(1C)) and skeletal (alpha(1S)) muscle differ from one another in ion selectivity and permeation properties, including unitary conductance. In 110 mM Ba(2+), unitary conductance of alpha(1S) is approximately half that of alpha(1C). As a step toward understanding th... |
12609865 | Forces and pressures in DNA packaging and release from viral capsids. | In a previous communication (Kindt et al., 2001) we reported preliminary results of Brownian dynamics simulation and analytical theory which address the packaging and ejection forces involving DNA in bacteriophage capsids. In the present work we provide a systematic formulation of the underlying theory, featuring the e... |
12606074 | Non-covalent interaction between nucleocapsid protein of Tula hantavirus and small ubiquitin-related modifier-1, SUMO-1. | To find cellular binding counterparts for the nucleocapsid protein (N) of Tula hantavirus (TULV), two cDNA libraries were screened using yeast two-hybrid systems based on LexA and Gal4 transcription factors. Five cDNA clones encoding SUMO-1 (Small Ubiquitin-related MOdifier, also known as sentrin) were selected in the ... |
12605491 | Hydrogen bond-assembled fullerene molecular shuttle. | A novel [2]rotaxane has been prepared in which fullerene C(60) behaves as both a stopper and a photoactive unit. The amphiphilic nature of the rotaxane thread can be used to shuttle the macrocycle from close to the fullerene spheroid (in nonpolar solvents) to far away (in polar solvents). The differing location of the ... |
12606572 | The human chromokinesin Kid is a plus end-directed microtubule-based motor. | Kid is a kinesin-like DNA-binding protein known to be involved in chromosome movement during mitosis, although its actual motor function has not been demonstrated. Here, we describe the initial characterization of Kid as a microtubule-based motor using optical trapping microscopy. A bacterially expressed fusion protein... |
12606564 | Structural view of a fungal toxin acting on a 14-3-3 regulatory complex. | The fungal phytotoxin fusicoccin stabilizes the interaction between the C-terminus of the plant plasma membrane H(+)-ATPase and 14-3-3 proteins, thus leading to permanent activation of the proton pump. This results in an irreversible opening of the stomatal pore, followed by wilting of plants. Here, we report the cryst... |
12605231 | The nature of molecular recognition by T cells. | Considerable progress has been made in characterizing four key sets of interactions controlling antigen responsiveness in T cells, involving the following: the T cell antigen receptor, its coreceptors CD4 and CD8, the costimulatory receptors CD28 and CTLA-4, and the accessory molecule CD2. Complementary work has define... |
12603150 | Nanoscopic assemblies between supramolecular redox active metallodendrons and gold nanoparticles: synthesis, characterization, and selective recognition of H2PO4-, HSO4-, and adenosine-5'-triphosphate (ATP2-) anions. | Tri- and nonaferrocenyl thiol dendrons have been synthesized and used to assemble dendronized gold nanoparticles either by the ligand-substitution method from dodecanethiolate-gold nanoparticles (AB(3) units) or Brust-type direct synthesis from a 1:1 mixture of dodecanethiol and dendronized thiol (AB(9) units). The den... |
12603107 | Hexameric macroring of gable-porphyrins as a light-harvesting antenna mimic. | Construction of a self-assembled supramolecular macroring that has distances and orientations of porphyrin dimer units in close analogy to those of the natural light-harvesting complexes was achieved. In natural light-harvesting complexes, bacteriochlorophyll-a's are arranged in macroring structures by coordination fro... |
12603319 | Site-directed mutagenesis of a loop at the active site of E1 (alpha2beta2) of the pyruvate dehydrogenase complex. A possible common sequence motif. | Limited proteolysis of the pyruvate decarboxylase (E1, alpha2beta2) component of the pyruvate dehydrogenase (PDH) multienzyme complex of Bacillus stearothermophilus has indicated the importance for catalysis of a site (Tyr281-Arg282) in the E1alpha subunit (Chauhan, H.J., Domingo, G.J., Jung, H.-I. & Perham, R.N. (2000... |
12604633 | Remodeling of the actin cytoskeleton during mammalian sperm capacitation and acrosome reaction. | The sperm acrosome reaction and penetration of the egg follow zona pellucida binding only if the sperm has previously undergone the poorly understood maturation process known as capacitation. We demonstrate here that in vitro capacitation of bull, ram, mouse, and human sperm was accompanied by a time-dependent increase... |
12601398 | Nonviral genetic transfer of Fas ligand induced significant growth suppression and apoptotic tumor cell death in prostate cancer in vivo. | To accomplish efficient nonviral gene therapy against prostate cancer (PC), Epstein-Barr virus (EBV)-based plasmid vectors containing EBNA1 gene and oriP were employed and combined with a cationic polymer or cationic lipid. When EBV-plasmid/poly-amidoamine dendrimer complex was injected into PC-3-derived tumors establi... |
12598501 | Progress in treatment and outcome for children with neonatal haemochromatosis. | <h4>Aim</h4>To evaluate the role of antioxidant treatment and liver transplantation in the management of neonatal haemochromatosis.<h4>Methods</h4>A retrospective review was performed of eight infants with acute liver failure and raised ferritin levels between 1990 and 1998. From 1994, treatment with an antioxidant coc... |
12598396 | Role of itraconazole in haematology/oncology. | The antifungal agents most frequently used in prophylaxis and treatment are amphotericin B (and its new lipid forms) and azoles such as fluconazole, itraconazole, and more recently voriconazole. This review assesses the role of itraconazole in paediatric haematology/oncology practice. Its broader spectrum of activity a... |
12598331 | cDNA microarray analysis of macroregenerative and dysplastic nodules in end-stage hepatitis C virus-induced cirrhosis. | Hepatocellular carcinoma is a common malignancy causing significant morbidity and mortality worldwide. In this study we use expression microarray technology to identify novel genes that consistently displayed altered expression levels in the earliest identifiable precursors to hepatocellular carcinoma, dysplastic and m... |
12598321 | Transfer of the alpha 5(IV) collagen chain gene to smooth muscle restores in vivo expression of the alpha 6(IV) collagen chain in a canine model of Alport syndrome. | X-linked Alport syndrome is a progressive renal disease caused by mutations in the COL4A5 gene, which encodes the alpha 5(IV) collagen chain. As an initial step toward gene therapy for Alport syndrome, we report on the expression of recombinant alpha 5(IV) collagen in vitro and in vivo. A full-length cDNA-encoding cani... |
12595560 | Sequence-specific minor groove binding by bis-benzimidazoles: water molecules in ligand recognition. | The binding of two symmetric bis-benzimidazole compounds, 2,2-bis-[4'-(3"-dimethylamino-1"-propyloxy)phenyl]-5,5-bi-1H-benzimidazole and its piperidinpropylphenyl analog, to the minor groove of DNA, have been studied by DNA footprinting, surface plasmon resonance (SPR) methods and molecular dynamics simulations in expl... |
12595472 | Mutant Escherichia coli heat-labile toxin B subunit that separates toxoid-mediated signaling and immunomodulatory action from trafficking and delivery functions. | The homopentameric B-subunit components of Escherichia coli heat-labile enterotoxin (EtxB) and cholera toxin (CtxB) possess the capacity to enter mammalian cells and to activate cell-signaling events in leukocytes that modulate immune cell function. Both properties have been attributed to the ability of the B subunits ... |
12595466 | Role of the Brucella suis lipopolysaccharide O antigen in phagosomal genesis and in inhibition of phagosome-lysosome fusion in murine macrophages. | Brucella species are gram-negative, facultative intracellular bacteria that infect humans and animals. These organisms can survive and replicate within a membrane-bound compartment inside professional and nonprofessional phagocytic cells. Inhibition of phagosome-lysosome fusion has been proposed as a mechanism for intr... |
12595448 | Complement activation influences Staphylococcus aureus adherence to endothelial cells. | The ability of Staphylococcus aureus to adhere to endothelial cells (EC) is a critical step in the development of metastatic infection. The role of complement in S. aureus binding to EC remains uninvestigated. Log-phase S. aureus, expressing minimal capsule, was incubated with serum under various conditions, washed, an... |
12596156 | Supramolecular control of two-dimensional phase behavior. | We have used directed two-component self-assembly to "pattern" organic monolayers on the nanometer scale at the liquid/solid interface. The ability of the scanning tunneling microscope to investigate structural details in these adlayers was used to gain insight into the two-component two-dimensional phase behavior. The... |
12596155 | Vilsmeier formylation of 5,10,15-triphenylcorrole: expected and unusual products. | 5,10,15-Triphenylcorrole (1) reacts with the Vilsmeier reagent (POCl(3)/DMF) to give the corresponding 3-formyl derivative 3 as the major product. The regioselectivity of the reaction was proven by X-ray crystallography and only traces of the 2-formyl isomer were observed. A more polar product is also observed and this... |
12596152 | Complexation behavior of a highly preorganized 7,7-diphenylnorbornane-derived macrocycle: towards the design of molecular clocks. | The syntheses of two new cyclophane hosts, 4 and 6, are described. The main difference between them is the higher degree of preorganization of 4 as a consequence of the inclusion of the 7,7-diphenylnorbornane (DPN) subunit. The inner cavity of 4 adopts a belt-shaped structure, while 6 has a twisted geometry. In the sol... |
12596151 | Structural regulation of a peptide-conjugated graft copolymer: a simple model for amyloid formation. | The self-assembly of peptides and proteins into beta-sheet-rich high-order structures has attracted much attention as a result of the characteristic nanostructure of these assemblies and because of their association with neurodegenerative diseases. Here we report the structural and conformational properties of a peptid... |
12595077 | In vitro interaction of macrocyclic photosensitizers with intact mitochondria: a spectroscopic study. | Six water-soluble macrocyclic photosensitizers, the members of two groups of expanded porphyrins (metallotexaphyrins and free-base sapphyrins) containing hydrophilic substituents and meso-tetra(4-sulfonatophenyl)-porphyrin, were tested by UV-Vis absorption and resonance Raman spectroscopy in the in vitro binding experi... |
12593941 | Effect of PVP K-25 on the formation of the naproxen:beta-ciclodextrin complex. | The aim of this study was to investigate the effects of the presence of the water-soluble polymer polyvinylpyrrolidone K-25 (MW=24000g/mol) on the complexation of the AINE naproxen, in its sodium salt form, with the beta-cyclodextrin. The data revealed that the polyvinylpyrrolidone K-25 interacts with the drug as well ... |
12593938 | In vitro cellular interaction and absorption of dispersed cubic particles. | A precursor type oily liquid formulation comprising monoolein, Pluronic F-127 and ethanol has been prepared as a carrier for lipophilic drugs. When dispersed in water, the liquid precursor formulation produces sub-micron (200-500 nm) sized lipid particles, named 'nanocubicles'. The interaction between nanocubicles and ... |
12593934 | Para-acyl-calix-arene based solid lipid nanoparticles (SLNs): a detailed study of preparation and stability parameters. | The preparation and stability parameters of para-acyl-calix[4]arene based solid lipid nanoparticles (SLNs) have been investigated. Atomic force microscopy (AFM) and photon correlation spectroscopy (PCS) show a mean particle size of 130 nm. In terms of preparation parameters, using the solvent displacement method, the n... |
12593932 | Mechanistic studies of the effect of hydroxypropyl-beta-cyclodextrin on in vitro transdermal permeation of corticosterone through hairless mouse skin. | Literature reports reveal that the issue of whether cyclodextrins may act as skin permeation enhancers has not been resolved. Accordingly, in vitro skin transport studies were conducted to address this question. Corticosterone (3H-CS and/or non-radiolabeled CS) was chosen as the model permeant for transport experiments... |
12592008 | Viroid RNA systemic spread may depend on the interaction of a 71-nucleotide bulged hairpin with the host protein VirP1. | Viroids are noncoding circular single-stranded RNAs that are propagated systemically in plants. VirP1 is a protein from tomato, which is an excellent host for potato spindle tuber viroid (PSTVd), and it has been isolated by virtue of its specific in vitro binding to PSTVd RNA. We report on the specific in vivo interact... |
12592033 | Prediction of beta-turns in proteins from multiple alignment using neural network. | A neural network-based method has been developed for the prediction of beta-turns in proteins by using multiple sequence alignment. Two feed-forward back-propagation networks with a single hidden layer are used where the first-sequence structure network is trained with the multiple sequence alignment in the form of PSI... |
12592026 | Reinvestigation of the proposed folding and self-association of the Neuropeptide Head Activator. | The Neuropeptide Head Activator (HA), pGlu-Pro-Pro-Gly-Gly-Ser-Lys-Val-Ile-Leu-Phe (pGlu is pyroglutamic acid), is involved in head-specific growth and differentiation processes in the freshwater coelenterate Hydra attenuata. Peptides of identical sequence have also been isolated from higher-organism tissues such as hu... |
12592024 | Interplay between hydrophobic cluster and loop propensity in beta-hairpin formation: a mechanistic study. | We investigated the structural determinants of the stability of a designed beta-hairpin containing a natural hydrophobic cluster from the protein GB1 and a D-Pro-Gly turn forming sequence. The results of our simulations shed light on the factors leading to an ordered secondary structure in a model peptide: in particula... |
12592011 | Simultaneous assignment and structure determination of a membrane protein from NMR orientational restraints. | A solid-state NMR approach for simultaneous resonance assignment and three-dimensional structure determination of a membrane protein in lipid bilayers is described. The approach is based on the scattering, hence the descriptor "shotgun," of (15)N-labeled amino acids throughout the protein sequence (and the resulting NM... |
12413396 | Thermodynamic characterization of a tetrahaem cytochrome isolated from a facultative aerobic bacterium, Shewanella frigidimarina: a putative redox model for flavocytochrome c3. | The facultative aerobic bacterium Shewanella frigidimarina produces a small c-type tetrahaem cytochrome (86 residues) under anaerobic growth conditions. This protein is involved in the respiration of iron and shares 42% sequence identity with the N-terminal domain of a soluble flavocytochrome, isolated from the peripla... |
12408752 | Identification and functional analysis of enzymes required for precorrin-2 dehydrogenation and metal ion insertion in the biosynthesis of sirohaem and cobalamin in Bacillus megaterium. | In Bacillus megaterium, the hemAXBCDL genes were isolated and were found to be highly similar to the genes from Bacillus subtilis that are required for the conversion of glutamyl-tRNA into uroporphyrinogen III. Overproduction and purification of HemC (porphobilinogen deaminase) and -D (uroporphyrinogen III synthase) al... |
12588980 | Delayed rRNA processing results in significant ribosome biogenesis and functional defects. | mof6-1 was originally isolated as a recessive mutation in Saccharomyces cerevisiae which promoted increased efficiencies of programmed -1 ribosomal frameshifting and rendered cells unable to maintain the killer virus. Here, we demonstrate that mof6-1 is a unique allele of the histone deacetylase RPD3, that the deacetyl... |
12587126 | Interaction of artemisinin and its related compounds with hydroxypropyl-beta-cyclodextrin in solution state: experimental and molecular-modeling studies. | Hydroxypropyl-beta-cyclodextrin (HPBCD) was investigated as a possible solubilizer for a series of poorly water-soluble antimalarial drugs. The solubilities of artemisinin, artether, dihydroartemisinin, and 10-deoxoartemisinin in HPBCD solutions were studied. The phase-solubility profile of these drugs in HPBCD solutio... |
12584360 | Defects in virion production caused by mutations affecting the C-terminal portion of the Moloney murine leukemia virus capsid protein. | The capsid (CA) domain of the Moloney murine leukemia virus (Mo-MuLV) Gag protein has a unique carboxy terminus with a highly charged arginine-rich sequence. Mutant viruses harboring arginine-to-alanine mutations affecting this region of CA displayed significant defects in virion release, and the few viral particles pr... |
12584348 | Effects of point mutations in the major capsid protein of beet western yellows virus on capsid formation, virus accumulation, and aphid transmission. | Point mutations were introduced into the major capsid protein (P3) of cloned infectious cDNA of the polerovirus beet western yellows virus (BWYV) by manipulation of cloned infectious cDNA. Seven mutations targeted sites on the S domain predicted to lie on the capsid surface. An eighth mutation eliminated two arginine r... |
12584332 | Cellular proteins from human monocytes bind to dengue 4 virus minus-strand 3' untranslated region RNA. | The synthesis of plus and minus RNA strands of several RNA viruses requires as a first step the interaction of some viral regulatory sequences with cellular and viral proteins. The dengue 4 virus genome, a single-stranded, positive-polarity RNA, is flanked by two untranslated regions (UTR) located in the 5' and 3' ends... |
12584324 | Mutation of host DnaJ homolog inhibits brome mosaic virus negative-strand RNA synthesis. | The replication of positive-strand RNA viruses involves not only viral proteins but also multiple cellular proteins and intracellular membranes. In both plant cells and the yeast Saccharomyces cerevisiae, brome mosaic virus (BMV), a member of the alphavirus-like superfamily, replicates its RNA in endoplasmic reticulum ... |
12584319 | Exonuclease-deficient polymerase mutant of herpes simplex virus type 1 induces altered spectra of mutations. | The effect of exonuclease activity of the herpes simplex virus DNA polymerase (Pol) on DNA replication fidelity was examined by using the supF mutagenesis assay. The recombinants with exonuclease-deficient Pol, containing an integrated supF gene in the thymidine kinase locus (tk), exhibited supF mutation frequencies ra... |
12584249 | Distinct caveolae-mediated endocytic pathways target the Golgi apparatus and the endoplasmic reticulum. | Internalization of autocrine motility factor (AMF) into the endoplasmic reticulum is sensitive to the cholesterol-extracting reagent methyl-beta-cyclodextrin, inhibited by the dynamin-1 K44A mutant and negatively regulated by caveolin-1. Thus, AMF internalization requires a caveolae-mediated endocytic pathway. Similarl... |
12582993 | Chiral reagents for the determination of enantiomeric excess and absolute configuration using NMR spectroscopy. | Recent advances in the development of chiral derivatizing and solvating agents that facilitate the determination of enantiomeric excess and absolute configuration are reviewed. These include metal-containing species, host-guest systems, donor-acceptor compounds, and liquid crystal discriminating agents. In the aggregat... |
12579561 | Mixed-ligand modification of polyamidoamine dendrimers to develop an effective scaffold for maintenance of hepatocyte spheroids. | Compared with a monolayer culture, hepatocyte spheroids are known to maintain liver function for long periods. We found that hepatocytes formed spheroids when cultured on polyamidoamine dendrimers modified with fructose. Because galactose is a ligand for the asialoglycoprotein receptor on the hepatocyte cytoplasmic mem... |
12579517 | Effects of steroid hormones on five functional parameters of Tetrahymena: evolutionary conclusions. | The unicellular Tetrahymena pyriformis was studied for chemotaxis, chemotactic selection, phagocytosis, growth and body shape changes in the presence of water soluble (beta-cyclodextrin-coupled) steroid hormones (testosterone, estradiol, progesterone, hydrocortisone and dexamethasone). Testosterone was chemoattractant ... |
12577267 | The role of electrostatic interaction in the molecular recognition of selective agonists to metabotropic glutamate receptors. | The influence of electrostatic interactions in determining selectivity for individual subtypes of metabotropic glutamate receptors (mGluRs) is evaluated for a small set of agonists by using the program Delphi and the information thus obtained is compared with docking experiments carried out with AutoDock. The evaluatio... |
12576874 | Platelet derived growth factor-BB is a potent mitogen for rat ureteral and human bladder smooth muscle cells: dependence on lipid rafts for cell signaling. | <h4>Purpose</h4>Fibromuscular tissues of the detrusor/bladder body (B), trigone (T) and ureter (U) display distinct patterns of tissue remodeling in pathologic contexts, however the mechanisms underlying these observations are unknown. In this study we asked whether B, T and U smooth muscle cells (SMC) respond to sever... |
12570843 | New progresses in the enantioselective synthesis and biological properties of carbocyclic nucleosides. | The recent advances in the chemistry of carbocyclic nucleosides focused on different synthetic approaches that lead to optically pure products as well as a comprehensive overview of their biological properties are discussed. In the latter aspect, molecular recognition of enzymes of pharmacological importance such as: r... |
12543133 | Designing supramolecular structures from models of cyclic peptide scaffolds with heterocyclic constraints. | Cyclic peptides containing oxazole and thiazole heterocycles have been examined for their capacity to be used as scaffolds in larger, more complex, protein-like structures. Both the macrocyclic scaffolds and the supramolecular structures derived therefrom have been visualised by molecular modelling techniques. These mo... |
12529888 | Transglutaminase-catalyzed synthesis of trypsin-cyclodextrin conjugates: kinetics and stability properties. | Bovine pancreatic trypsin was modified by the mono-6-amino-6-deoxy derivatives of alpha-, beta-, and gamma-cyclodextrin through a transglutaminase-catalyzed reaction. The trypsin-cyclodextrin conjugates, containing about 3 mol of oligosaccharide per mole of protein, were tested for their catalytic and stability propert... |
12527253 | In vitro cytotoxicity testing of polycations: influence of polymer structure on cell viability and hemolysis. | A comparative in vitro cytotoxicity study with different water-soluble, cationic macromolecules which have been described as gene delivery systems was performed. Cytotoxicity in L929 mouse fibroblasts was monitored using the MTT assay and the release of the cytosolic enzyme lactate dehydrogenase (LDH). Microscopic obse... |
12504530 | Surface effects and desorption of tetracycline supramolecular complex on bovine dentine. | The aim of this in vitro study was to evaluate the antimicrobial activity, the substantivity, and surface effects of the inclusion compound tetracycline: beta-cyclodextrin on bovine roots. The antimicrobial activity was assessed by dentine slabs which had been immersed in the inclusion complex in concentrations 8.0%, 4... |
12929651 | Facile resolution of racemic terbutaline and a study of molecular recognition through chiral supramolecules based on enantiodifferentiating self-assembly. | An effective resolving agent, (2S, 3S)-di-O-(p-toluoyl) tartaric acid(4), was screened using a 'family' approach to yield direct resolution of (R)-terbutaline (1) with high optical purity and yield. Molecular recognition was studied by X-ray crystallographic analyses of the single crystals of the pair of diastereomeric... |
12929375 | Diazacoronand linked beta-cyclodextrin dimer complexes of Brilliant Yellow tetraanion and their sodium(I) analogues. | Complexation of the Brilliant Yellow tetraanion, 3(4-), by two new diazacoronand linked beta-cyclodextrin (beta CD) dimers 4,13-bis(2-(6A-deoxy-beta-cyclodextrin-6A-yl)aminooctylamidomethyl- and 4,13-bis(8-(6A-deoxy-beta-cyclodextrin-6A-yl)aminooctylamidomethyl)-4,13- diaza-1,7,10-trioxacyclopentadecane, 1 and 2, respe... |
12929374 | Synthesis, characterization and coordination chemistry of the new tetraazamacrocycle 4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-bis(methanephosphonic acid monoethyl ester) dipotassium salt. | A new potentially hexadentate tetraazamacrocycle based on the cyclen skeleton has been synthesized and fully characterized. The macrocycle 4,10-dimethyl-1,4,7,10-tetraazacyclododecane-1,7-bis(methanephosphonic acid monoethyl ester) dipotassium salt (Me2DO2PME) contains mutually trans monoethyl ester phosphonate acid su... |
12929373 | Encapsulation of sodium nimesulide and precursors in beta-cyclodextrin. | Crystalline 1:1 inclusion complexes with beta-cyclodextrin (beta-CD) and the sodium salt of nimesulide (4-nitro-2-phenoxymethanesulfonanilide), and the sodium salt of the derivative 2-phenoxymethanesulfonanilide, have been prepared by co-precipitation from aqueous solution. The presence of true inclusion complexes was ... |
12929370 | Preparation of hexaaza and heptaaza macrocycles functionalized with a single aminoalkyl pendant arm. | A practical and reproducible route for the preparation of 1,4,7,10,13,16,19-heptaazacyclohenicosane (1), 1,4,7,10,13,16-hexaazacyclooctadecane (2), and 1,4,7,10,13,17-hexaazacycloicosane (3) bearing a single N-(2-aminoethyl) pendant arm has been developed. Richman-Atkins cyclization in the presence of caesium carbonate... |
12901606 | Angiotensin II-acetylcholine noncovalent complexes analyzed with MALDI-ion mobility-TOF MS. | Matrix-assisted laser desorption ionization-ion mobility-orthogonal time-of-flight mass spectrometry (MALDI-IM oTOF MS) is a new technique that allows laser desorbed ion to be preseparated on the basis of their shape prior to mas analysis. Using this instrument, we tested the postulate that addition of a quaternary amm... |
12871469 | Role of in vitro cholesterol depletion in mediating human platelet aggregation. | We investigated the direct role of cholesterol lowering on human platelet aggregation by in vitro cholesterol depletion using methyl-beta-cyclodextrin. Collagen and thrombin receptor agonist peptide induced maximal aggregation was significantly decreased in cholesterol depleted platelets. In contrast, anti-CD9 antibody... |
15015310 | [Study on selective isolation of volatile oil in the seed of Fructus foeniculi]. | <h4>Objective</h4>To study the selective isolation of a single chemical component from volatile oil of Fructus foeniculi by inclucion method.<h4>Method</h4>The host molecule was selected and a single chemical component isolated from volatile oil by the host-guest recognition.<h4>Result</h4>X-ray single crystal analysis... |
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