id stringlengths 4 8 | title stringlengths 1 642 | abstract stringlengths 50 17.9k |
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14552627 | Nickel(II) cyclidenes with appended ethylpyridine receptor centers as molecular tweezers for dicarboxylic acids. | A series of 14-, 15-, and 16-membered nickel(II) cyclidene macrocycles appended with 2-aminoethyl(2-pyridine) receptors I-III, respectively, were prepared and characterized by X-ray crystallography and NMR techniques. The 14- and 15-membered macrocycles I and II exist in a planar or extended Z-configuration, whereas th... |
14552611 | Octadecanuclear cluster or 1D polymer with [[ML](2)Nb(CN)(8)](n) motifs as a function of [ML] (M = Ni(II), n = 6; M = Mn(II), n = infinity; L = macrocycle). | A nanosized octadecaheteronuclear aggregate, [[NiL(2)](12)[Nb(CN)(8)](6)(H(2)O)(6)], and a 1-D coordination polymer, [[MnL(1)](2)[Nb(CN)(8)](H(2)O)]( infinity ), have been obtained by self-assembly between the octacyanometalate [Nb(CN)(8)](4)(-) and [ML](2+) complexes. The dimensionality of the supramolecular architect... |
14552610 | Formation of a spiral-shaped inorganic-organic hybrid chain, [Cu(II)(2,2'-bipy)(H(2)O)(2)Al(OH)(6)Mo(6)O(18)](n)()(n)()(-): influence of intra- and interchain supramolecular interactions. | A novel chainlike coordination polymer [Cu(II)(2,2'-bipy)(H(2)O)(2)Al(OH)(6)Mo(6)O(18)](n)()(n)()(-), formed from a heteropolyanion [Al(OH)(6)Mo(6)O(18)](3)(-) as a building unit and a copper(II) complex fragment, [Cu(II)(2,2'-bipy)(H(2)O)(2)](2+), as a linker, provides the first example of an extended structure based ... |
14555526 | Nonviral cytokine gene therapy on an orthotopic bladder cancer model. | <h4>Purpose</h4>The purpose is to assess cytokine gene transfection in tumor cells and its therapeutic efficacy in an orthotopic mouse bladder cancer model after liposome-mediated gene transfer.<h4>Experimental design</h4>A total of 1 x 10(5) MB49 cells was instilled into the bladder of C57BL/6 mice after electrocauter... |
14553984 | Imazalil-cyclomaltoheptaose (beta-cyclodextrin) inclusion complex: preparation by supercritical carbon dioxide and 13C CPMAS and 1H NMR characterization. | An inclusion complex between imazalil (IMZ), a selected fungicide, and cyclomaltoheptaose (beta-cyclodextrin, betaCD) was obtained using supercritical fluid carbon dioxide. The best preparation conditions were determined, and the inclusion complex was investigated by means of 1H NMR spectroscopy in aqueous solution and... |
14553983 | Preparation and reactivity of a novel disaccharide, glucosyl 1,5-anhydro-D-fructose (1,5-anhydro-3-O-alpha-glucopyranosyl-D-fructose). | A novel disaccharide, glucosyl 1,5-anhydro-D-fructose (1,5-anhydro-3-O-alpha-glucopyranosyl-D-fructose, GAF) was enzymatically prepared from 1,5-anhydro-D-fructose (1,5-AF) and cyclomaltoheptaose (beta-cyclodextrin). Cyclodextrin glucanotransferase transferred various sizes of maltooligosaccharide to 1,5-AF. Glucoamyla... |
14553979 | Synthesis and characterisation of sulfated amphiphilic alpha-, beta- and gamma-cyclodextrins: application to the complexation of acyclovir. | The synthesis of sulfated amphiphilic alpha-, beta- and gamma-cyclodextrins was achieved according to the standard protection-deprotection procedure. The formation of inclusion complexes between the amphiphilic alpha-, beta- and gamma-cyclodextrins and an antiviral molecule, acyclovir (ACV) was investigated by UV-visib... |
14535764 | Molecular recognition of anions through hydrogen bonding stabilization of anion-ionophore adducts: a novel trifluoroacetophenone-based binding motif. | [reaction: see text] A novel trifluoroacetophenone-based binding motif has been developed that recognizes anions such as carboxylates through reversible formation of anion-ionophore adducts that are stabilized by intramolecular H-bonding. The intramolecular H-bonding resulted in more than 10-fold enhancement in the bin... |
14535762 | Enantioselective [4 + 2]-annulation of chiral crotylsilanes: application to the synthesis of a C1-C22 fragment of leucascandrolide A. | [reaction: see text] The asymmetric synthesis of a C1-C22 fragment (2) of leucascandrolide A is described. Synthetic highlights include the construction of the C9-C22 pyran fragment using a formal [4 + 2]-annulation of a chiral organosilane. A diastereoselctive Mukaiyama aldol was used to introduce the C9 stereocenter ... |
14535751 | Conformational and electronic engineering of twisted diphenylacetylenes. | [structure: see text] Three tethered diphenylacetylene derivatives were prepared by alkyne metathesis. In these cycles, the twist angle between the two benzene rings is variable and determined by the nature of the linker. The engineering of the twist angle leads to a change of the UV-vis spectra of the cycles. The larg... |
14535709 | Dynamic multivalent lactosides displayed on cyclodextrin beads dangling from polymer strings. | [reaction: see text] Lactose-appended cyclodextrin derivatives have been synthesized and threaded onto hydrophobic polymers in aqueous solution to form dynamic multivalent lactosides for binding to lectins. The threading process, which proceeds quickly, can be observed by one- and two-dimensional NMR spectroscopies. |
14550865 | Determination of heroin metabolites in human urine using capillary zone electrophoresis with beta-cyclodextrin and UV detection. | A method has been developed for the detection of a mixture of morphine, codeine, 6-acetyl morphine (6-AM) and normorphine using capillary zone electrophoresis (CZE). The method utilized urinary 6-AM as a diagnostic indicator of heroin abuse because it is not a product of either morphine or codeine metabolism. The elect... |
14535805 | The nicotinic pharmacophore: thermodynamics of the hydrogen-bonding complexation of nicotine, nornicotine, and models. | The thermodynamics of the hydrogen-bonding complexation of the acetylcholine agonists nicotine and nornicotine and of model pyridines, pyrrolidines, and N-methylpyrrolidines has been measured in CCl(4) by FTIR spectrometry toward a reference hydrogen-bond donor, 4-fluorophenol. Various methods are devised for measuring... |
14550885 | Driving forces and the influence of the buffer composition on the complexation reaction between ibuprofen and HPCD. | Cyclodextrins are often used in order to increase the aqueous solubility of drug substances by complexation. In order to investigate the complexation reaction of ibuprofen and hydroxypropyl-beta-cyclodextrin, titration calorimetry was used as a direct method. The thermodynamic parameters of the complexation process (st... |
14536060 | ER-to-Golgi carriers arise through direct en bloc protrusion and multistage maturation of specialized ER exit domains. | Protein transport between the ER and the Golgi in mammalian cells occurs via large pleiomorphic carriers, and most current models suggest that these are formed by the fusion of small ER-derived COPII vesicles. We have examined the dynamics and structural features of these carriers during and after their formation from ... |
14534146 | Designer blood vessels and therapeutic revascularization. | Inadequate vascular perfusion leads to fatal heart attacks, chronic ulcers, and other serious clinical conditions. The body's capacity to restore vascular perfusion through angiogenesis and arteriogenesis is often impaired by pre-existing disease, and availability of native replacements for nonfunctional arteries is li... |
14531701 | Dendrimeric organochalcogen catalysts for the activation of hydrogen peroxide: origins of the "dendrimer effect" with catalysts terminating in phenylseleno groups. | Several scenarios were evaluated to explain the large "dendrimer effect" observed in the bromination of cyclohexene with H(2)O(2) and NaBr catalyzed by the addition of Frechét-type dendrimers terminating in -O(CH(2))(3)SePh groups. Although phenylseleninic acid was an efficient catalyst for the oxidation of NaBr with H... |
14531691 | Structure of microcin J25, a peptide inhibitor of bacterial RNA polymerase, is a lassoed tail. | Microcin J25 (MccJ25) is a 21-amino acid peptide inhibitor active against the DNA-dependent RNA polymerase of Gram negative bacteria. Previously, the structure of MccJ25 was reported to be a head-to-tail circle, cyclo(-G(1)GAGHVPEYF(10)VGIGTPISFY(20)G-). On the basis of biochemical studies, mass spectrometry, and NMR, ... |
14531685 | Extended pi-conjugated dendrimers based on truxene. | The largest pi-conjugated dendrimers containing up to nine 10,15-dihydro-5H-diindeno[1,2-alpha;1',2';-c]fluorene (truxene) moieties have been prepared with good yields by repetitive Friedel-Crafts acetylation and acid-promoted cyclotrimerization reactions. An alternative approach to the convergent synthesis of desired ... |
14531670 | Single-crystal-to-single-crystal topochemical polymerizations of a terminal diacetylene: two remarkable transformations give the same conjugated polymer. | Host-guest chemistry was used to prepare a cocrystal of a dipyridyl substituted oxalamide host and a resorcinol derivative of a terminal diacetylene. X-ray crystallography revealed that the molecules assemble into a triple-helix with the diacetylene functionalities aligned in the center of the helix. Upon heating, the ... |
14532128 | Peripheral regions of natural hammerhead ribozymes greatly increase their self-cleavage activity. | Natural hammerhead ribozymes are mostly found in some viroid and viroid-like RNAs and catalyze their cis cleavage during replication. Hammerheads have been manipulated to act in trans and assumed to have a similar catalytic behavior in this artificial context. However, we show here that two natural cis-acting hammerhea... |
14529619 | S-adenosyl methionine prevents promiscuous DNA cleavage by the EcoP1I type III restriction enzyme. | DNA cleavage by the type III restriction endonuclease EcoP1I was analysed on circular and catenane DNA in a variety of buffers with different salts. In the presence of the cofactor S-adenosyl methionine (AdoMet), and irrespective of buffer, only substrates with two EcoP1I sites in inverted repeat were susceptible to cl... |
14530093 | Efficient determination and evaluation of model cyclodextrin complex binding constants by electrospray mass spectrometry. | Electrospray ionization mass spectrometry (ESI-MS) is now routinely used for the detection of cyclodextrin noncovalent complexes, complementing previously established methods. Host-guest complexes formed in solution are also stable for characterization by ESI in the gas phase. This paper reports the first investigation... |
14530092 | Identification of face-to-face inclusion complex formation of cyclodextrin bearing an azobenzene group by electrospray ionization mass spectrometry. | The solution-based self-assembly of native and permethylated cyclodextrins (CD) bearing an azobenzene substituent has been studied by electrospray ionization mass spectrometry (ESI-MS). The results revealed that the CD molecules form either a contact or a face-to-face inclusion complex depending on the interaction of t... |
14530091 | Evaluation of photoinduced changes in stability constants for metal-ion complexes of crowned spirobenzopyran derivatives by electrospray ionization mass spectrometry. | The photoinduced changes of metal-ion complexing ability of crowned spirobenzopyran derivatives were studied by using electrospray ionization mass spectrometry (ESI-MS). Stability constants for the complexation with various metal ions in methanol under visible-irradiation conditions were determined for the first time b... |
14529530 | Structural biology of the cell adhesion protein CD2: from molecular recognition to protein folding and design. | CD2 (cluster of differentiation 2) is a cell adhesion molecule expressed on T cells and is recognized as a target for CD48 (rats) and CD58 (humans). Tremendous progress has been achieved in understanding the function of CD2, the mechanism of molecular recognition and protein folding, thus, leading towards the use of th... |
14529292 | Cholesterol depletion inhibits store-operated calcium currents and exocytotic membrane fusion in RBL-2H3 cells. | The effects of cholesterol depletion from the plasma membrane with methyl-beta-cyclodextrin (MbetaCD) on exocytotic processes were investigated in rat basophil leukemia cells (RBL-2H3 cells). Pretreatment of the cells with MbetaCD inhibited antigen-evoked exocytotic release dose-dependently. To elucidate the mechanism ... |
14527391 | The atomic structure of rice dwarf virus reveals the self-assembly mechanism of component proteins. | Rice dwarf virus (RDV), the causal agent of rice dwarf disease, is a member of the genus Phytoreovirus in the family Reoviridae. RDV is a double-shelled virus with a molecular mass of approximately 70 million Dalton. This virus is widely prevalent and is one of the viruses that cause the most economic damage in many As... |
14527389 | Molecular recognition of paxillin LD motifs by the focal adhesion targeting domain. | Focal adhesions (FAs) are large submembrane signaling complexes formed at sites of cellular attachment to the extracellular matrix. The interaction of LD motifs with their targets plays an important role in the assembly of FAs. We have determined the molecular basis for the recognition of two paxillin LD motifs by the ... |
14527557 | A system of protein target sequences for anti-RNA-viral chemotherapy by a vitamin B6-derived zinc-chelating trioxa-adamantane-triol. | The synthesis of the structurally unusual heterotricyclic compound 1-[3-hydroxy-5-(hydroxymethyl)-2-methyl-4-pyridinyl]-2,8,9-trioxaadamantane-3,5,7-triol (trivially named bananin, BN) from pyridoxylidenephloroglucinol and a theoretical prospect on possible biological activities of BN are presented in this report. Pyri... |
12892563 | Investigating interactions of the pentraxins serum amyloid P component and C-reactive protein by mass spectrometry. | The oligomeric state of human SAP (serum amyloid P component) in the absence and presence of known ligands has been investigated using nanoelectrospray ionization MS. At pH 8.0, in the absence of Ca2+, SAP has been shown to consist of pentameric and decameric forms. In the presence of physiological levels of Ca2+, SAP ... |
12852786 | Role of flanking sequences and phosphorylation in the recognition of the simian-virus-40 large T-antigen nuclear localization sequences by importin-alpha. | The nuclear import of simian-virus-40 large T-antigen (tumour antigen) is enhanced via phosphorylation by the protein kinase CK2 at Ser112 in the vicinity of the NLS (nuclear localization sequence). To determine the structural basis of the effect of the sequences flanking the basic cluster KKKRK, and the effect of phos... |
14526081 | Self-assembly of proteins into designed networks. | A C4-symmetric tetrameric aldolase was used to produce a quadratic network consisting of the enzyme as a rigid four-way connector and stiff streptavidin rods as spacers. Each aldolase subunit was furnished with a His6 tag for oriented binding to a planar surface and two tethered biotins for binding streptavidin in an o... |
14523962 | Comparison of dendrimer-based macromolecular contrast agents for dynamic micro-magnetic resonance lymphangiography. | Few methods are currently available to visualize the entire lymphatic system. A method known as micro-magnetic resonance lymphangiography (MRL), which employs a dendrimer-based MRI contrast agent (PAMAM-G8) and a clinical-grade 1.5T MRI instrument, was recently developed for use in mice. In the present study, three den... |
14521405 | Structure-based design of novel guanidine/benzamidine mimics: potent and orally bioavailable factor Xa inhibitors as novel anticoagulants. | As part of an ongoing effort to prepare orally active factor Xa inhibitors using structure-based drug design techniques and molecular recognition principles, a systematic study has been performed on the pharmacokinetic profile resulting from replacing the benzamidine in the P1 position with less basic benzamidine mimic... |
14522128 | Transport mechanism(s) of poly (amidoamine) dendrimers across Caco-2 cell monolayers. | The objective of this research was to investigate the mechanism(s) of transport of generation 2 (G2) poly (amidoamine) dendrimers across Caco-2 cell monolayers. The contribution of an energy-dependent process such as adsorptive endocytosis was investigated by determining G2 permeability at 4 and 37 degrees C. The contr... |
14522127 | Ternary naproxen: beta-cyclodextrin:polyethylene glycol complex formation. | The aim of this study was to investigate the effect of the presence of the water-soluble polymer polyethylene glycol (PEG)-MW=35000 g/mol-on the complexation of the phototoxic anti-inflammatory drug naproxen, in its sodium salt form, with beta-cyclodextrin (beta-CD). The data revealed that the polymer does not interact... |
14522125 | Design and monitoring of photostability systems for amlodipine dosage forms. | Photostability of amlodipine (AML) has been monitored in several pharmaceutical inclusion systems characterized by plurimolecular aggregation of the drug and excipients with high molecular weight. Several formulations including cyclodextrins, liposomes and microspheres have been prepared and characterized. The photodeg... |
14522121 | Formation of fine drug particle by cogrinding with cyclodextrins. Part II. The influence of moisture condition during cogrinding process on fine particle formation. | The purpose of this study was to investigate the effect of moisture condition during cogrinding process on fine drug particle formation. Cogrinding of cyclodextrins (CDs) and pranlukast (PRK) hemihydrate was performed in various moisture conditions at a mixing molar ratio of 2:1 (CDs:PRK) and the formation of PRK submi... |
14522114 | Preparation and in-vitro release rate of fentanyl-cyclodextrin complexes for prolonged action in epidural analgesia. | Fentanyl was complexed with cyclodextrin derivatives with the intention to obtain parenteral solutions able to provide prolonged analgesia following epidural administration. Three cylodextrins (CDs) suitable for parenteral use were used: hydroxypropyl-beta-cyclodextrin (HP-beta-CD), sulfobutylether-beta-cyclodextrin (S... |
14522949 | Beta1 integrins regulate chondrocyte rotation, G1 progression, and cytokinesis. | Beta1 integrins are highly expressed on chondrocytes, where they mediate adhesion to cartilage matrix proteins. To assess the functions of beta1 integrin during skeletogenesis, we inactivated the beta1 integrin gene in chondrocytes. We show here that these mutant mice develop a chondrodysplasia of various severity. bet... |
14521921 | A novel macrocyclic tetrapeptide mimetic that exhibits low-picomolar Grb2 SH2 domain-binding affinity. | The growth factor receptor-bound protein 2 (Grb2) is an SH2 domain-containing docking module that participates in the signaling of numerous oncogenic growth factor receptor protein-tyrosine kinases (PTKs). Presented herein is a 5-methylindolyl-containing macrocyclic tetrapeptide mimetic (5) that binds to Grb2 SH2 domai... |
14520402 | Fabrication of novel biomaterials through molecular self-assembly. | Two complementary strategies can be used in the fabrication of molecular biomaterials. In the 'top-down' approach, biomaterials are generated by stripping down a complex entity into its component parts (for example, paring a virus particle down to its capsid to form a viral cage). This contrasts with the 'bottom-up' ap... |
14519757 | The role of the combination of IL-2 and TGF-beta or IL-10 in the generation and function of CD4+ CD25+ and CD8+ regulatory T cell subsets. | Recently, considerable attention has been focused on thymus-derived CD4+ regulatory T cells that constitutively express CD25 and have a contact-dependent, cytokine-independent mechanism in vitro. However, peripheral CD4+ and CD8+ T cells can also be induced to become regulatory T cells. Here we review our studies using... |
14519016 | Dynamic equilibrium of a supramolecular dimeric rhomboid and trimeric hexagon and determination of its thermodynamic constants. | A supramolecular dimeric rhomboid and its trimeric counterpart, a hexagon, are generated by design via the directional bonding methodology of self-assembly. The different-sized supramolecular macrocycles formed by Pt-coordination undergo a concentration- and temperature-dependent dynamic equilibrium. The two structures... |
14519015 | Donor-acceptor phthalocyanine nanoaggregates. | A novel donor-acceptor bisphthalocyanine (bis-Pc, 1) in which two different Pc units (Zn(II)-Pc and Ni(II)-Pc) are linked via vinylene spacers to the pseudopara positions of a central [2.2]paracyclophane moiety is described. The synthesis of 1 is achieved by two successive Heck reactions of pseudopara-divinyl[2.2]parac... |
14519014 | Synthesis, photophysical and nonlinear optical properties of macromolecular architectures featuring octupolar tris(bipyridine) ruthenium(II) moieties: evidence for a supramolecular self-ordering in a dentritic structure. | The synthesis, photophysical and nonlinear optical properties of several new multi-octupolar tris(bipyridine) ruthenium complexes are reported. The preparation on these complexes is based on the initial construction of multipodal 4,4'-dialkylaminostyryl-2,2'-bipyridine ligands (DAAS-bpy). Thermally stable polyimides fe... |
14519013 | Solid-state supramolecular organization, established directly from powder diffraction data, and photoluminescence efficiency of rigid-core oligothiophene-S,S-dioxides. | The "rigid-core" material 3,5-dimethyl-2,3'-bis(3-methylthiophene)-dithieno[3,2-b:',3'-d]thiophene-4,4-dioxide (DTTOMe4) has the highest photoluminescence ever reported for thiophene-based molecules in the solid state. We report the structure of this material, determined directly from powder X-ray diffraction data usin... |
14519006 | Ordered reactive nanomembranes/nanotemplates from thin films of block copolymer supramolecular assembly. | We report on a unique, very simple method of preparation of reactive membranes and nanotemplates with nanoscopic cylindrical channels on the surface of various inorganic and polymeric substrates. Well-ordered nanostructured thin polymer films have been fabricated from the supramolecular assembly of poly(styrene-block-4... |
14518994 | Dendrimeric pyridoxamine enzyme mimics. | PAMAM dendrimers from generations 1-6 were synthesized with pyridoxamine in their core. They transaminated pyruvic and phenylpyruvic acids in water to alanine and phenylalanine, respectively, with Michaelis-Menten kinetics and high effectiveness compared with simple pyridoxamine. The largest dendrimers-similar in size ... |
14518987 | Dip-pen nanolithography of reactive alkoxysilanes on glass. | The use of organofunctional silane chemistry is a flexible and general method for immobilizing biomolecules on silicon oxide surfaces, including fabricating DNA, small-molecule, and protein microarrays. The biggest hurdle in employing dip-pen nanolithography (DPN) for extending this general approach to the nanoscopic d... |
14518974 | Novel polymer capsules from amphiphilic graft copolymers and cross-metathesis. | We report the synthesis of polymer capsules from amphiphilic graft copolymers composed of reactive, hydrophobic polyolefin backbones and hydrophilic poly(ethylene glycol) (PEG) grafts. The capsules are produced by self-assembly of the polymers at the oil-water interface, followed by cross-linking with bis-cyclooctene P... |
14518970 | pH responsive Eu(III)-phenanthroline supramolecular conjugate: novel "off-on-off" luminescent signaling in the physiological pH range. | The formation of luminescent supramolecular ternary complexes in water: delayed luminescence sensing of aromatic carboxylates using coordinated unsaturated cationic heptadenatate lanthanide ion complexes. |
14518933 | Enantioseparation of imazalil residue in orange by capillary electrophoresis with 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. | Chiral resolution of imazalil, a fungicide, was performed by capillary electrophoresis (CE) using 2-hydroxypropyl-beta-cyclodextrin as a chiral selector. Factors affecting the chiral resolution and migration time of imazalil were studied. The optimum running conditions were found to be 5 mM ammonium dihydrogenphosphate... |
14517259 | Unfolding pathways of native bacteriorhodopsin depend on temperature. | The combination of high-resolution atomic force microscopy (AFM) imaging and single-molecule force-spectroscopy was employed to unfold single bacteriorhodopsins (BR) from native purple membrane patches at various physiologically relevant temperatures. The unfolding spectra reveal detailed insight into the stability of ... |
14517244 | Activated EGL-15 FGF receptor promotes protein degradation in muscles of Caenorhabditis elegans. | Signaling by fibroblast growth factors (FGFs) and their receptors has been previously implicated in control of cell proliferation, differentiation and migration. Here we report a novel role for signaling by the EGL-15 FGFR of Caenorhabditis elegans in controlling protein degradation in differentiated muscle. Activation... |
14517240 | Thiol-mediated protein retention in the endoplasmic reticulum: the role of ERp44. | Formation of disulfide bonds, an essential step for the maturation and exit of secretory proteins from the endoplasmic reticulum (ER), is controlled by specific ER-resident enzymes. A pivotal element in this process is Ero1alpha, an oxidoreductin that lacks known ER retention motifs. Here we show that ERp44 mediates Er... |
14517237 | Clathrin self-assembly involves coordinated weak interactions favorable for cellular regulation. | The clathrin triskelion self-assembles into a polyhedral coat surrounding membrane vesicles that sort receptor cargo to the endocytic pathway. A triskelion comprises three clathrin heavy chains joined at their C-termini, extending into proximal and distal leg segments ending in a globular N-terminal domain. In the clat... |
14517236 | Single-molecule imaging of cooperative assembly of gamma-hemolysin on erythrocyte membranes. | Single-molecule fluorescence imaging was used to investigate assembly of Staphylococcus aureus LukF and HS monomers into pore-forming oligomers (gamma-hemolysin) on erythrocyte membranes. We distinguished the hetero-oligomers from the monomers, as indicated by fluorescence resonance energy transfer between different dy... |
14517232 | Crystal structure and snapshots along the reaction pathway of a family 51 alpha-L-arabinofuranosidase. | High-resolution crystal structures of alpha-L-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 glycosidase, are described. The enzyme is a hexamer, and each monomer is organized into two domains: a (beta/alpha)8-barrel and a 12-stranded beta sandwich with jelly-roll topology. The structures of t... |
14516194 | Procollagen VII self-assembly depends on site-specific interactions and is promoted by cleavage of the NC2 domain with procollagen C-proteinase. | Procollagen VII is a homotrimer of 350-kDa proalpha1(VII) chains. Each chain has a central collagenous domain flanked by a noncollagenous amino-terminal NC1 domain and a carboxy-terminal NC2 domain. After secretion from cells, procollagen VII molecules form antiparallel dimers with a 60 nm overlap. These dimers are sta... |
14514314 | Synthesis and photophysical properties of neutral luminescent rhenium-based molecular rectangles. | A series of neutral luminescent molecular rectangles [[Re(CO)(3)(mu-bpy)Br][Re(CO)(3)(mu-L)Br]](2) (1-4) having fac-Re(CO)(3)Br as corners and 4,4'-bipyridine (bpy) as the bridging ligand on one side and other bipyridyl ligands of varying length (L) on the other side have been synthesized and characterized. The crystal... |
14514301 | Synthesis of a single four-ring (S4R) molecular zinc phosphate and its assembly to an extended polymeric structure: a single-crystal and in-situ MAS NMR investigation. | A reaction of ZnO, HCl, H(3)PO(4), and 2-pyridylpiperazine in THF/H(2)O mixture at 75 degrees C for 72 h produces a new zinc phosphate, [(C(5)NH(5))(C(4)N(2)H(10))][Zn(H(2)PO(4))(2)(HPO(4))], I. Zinc phosphate I consists of single four-ring (S4R) units with terminal phosphoryl groups hanging from the Zn center. On reac... |
14512559 | Intermolecular interactions in a two-layered viral capsid that requires a complex symmetry mismatch. | The surface of the bluetongue virus core forms a T=13 quasiequivalent icosahedral protein shell with 260 trimers of a single gene product: VP7 protein. Underneath is a smooth layer, made up of VP3 protein, which appears to guide and nucleate the assembly of VP7 trimers. The contacts between the two shells are extensive... |
14512555 | Identification of a heparin-binding motif on adeno-associated virus type 2 capsids. | Infection of cells with adeno-associated virus (AAV) type 2 (AAV-2) is mediated by binding to heparan sulfate proteoglycan and can be competed by heparin. Mutational analysis of AAV-2 capsid proteins showed that a group of basic amino acids (arginines 484, 487, 585, and 588 and lysine 532) contribute to heparin and HeL... |
14512551 | Human T-cell lymphotropic virus type 1 p12I enhances interleukin-2 production during T-cell activation. | Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATLL) and a variety of lymphoproliferative disorders. The early virus-cell interactions that determine a productive infection remain unclear. However, it is well recognized that T-cell activation is required for effective retroviral ... |
14512534 | Role of the mutation Q252R in activating membrane fusion in the murine leukemia virus surface envelope protein. | Entry of retroviruses into host cells requires the fusion between the viral and cellular membranes. It is unclear how receptor binding induces conformational changes within the surface envelope protein (SU) that activate the fusion machinery residing in the transmembrane envelope protein (TM). In this report, we have i... |
14510532 | Selective syntheses of novel polyether fullerene multiple adducts. | We have applied a modified macrocyclic tether approach to control multiple additions to C60. The technique of 3He NMR was used to confirm the selective formation of specific C60 multiple adducts by the macrocyclic tether approach. An oligoglycol was used as a flexible linker to produce macrocyclic polyether-linked malo... |
14510531 | Ferrocenyl-bearing cyclopseudopeptides as redox-switchable cation receptors. | A family of ferrocenyl-bearing cyclopseudopeptides (1-10) designed for redox-switchable receptors of cations was synthesized. Circular dichroism (CD) and cyclic valtammetry (CV) studies of cation binding properties in both the reduced (K1) and oxidized (K2) forms revealed that the binding preference is mainly governed ... |
14511369 | On the mechanism of alpha-amylase. | Two inhibitors, acarbose and cyclodextrins (CD), were used to investigate the active site structure and function of barley alpha-amylase isozymes, AMY1 and AMY2. The hydrolysis of DP 4900-amylose, reduced (r) DP18-maltodextrin and maltoheptaose (catalysed by AMY1 and AMY2) was followed in the absence and in the presenc... |
14511689 | Resonance light scattering imaging detection of proteins with alpha,beta,gamma,delta-tetrakis(p-sulfophenyl)porphyrin. | A resonance light scattering (RLS) imaging technique was introduced to measure the light scattering of aggregation species induced by proteins, and thus a method of detecting proteins in the range of picograms was proposed. In acidic medium, J-aggregation of alpha,beta,gamma,delta-tetrakis(p-sulfophenyl)porphyrin (TPPS... |
14507172 | A switch in a cage with a memory. | [structure: see text] Chemical and optical stimulations control the interconversion of a three-state molecular switch trapped inside a silica monolith. The resulting absorbance changes in the visible region can be exploited to reproduce a sequential logic operator with one optical input and one optical output. This str... |
14507718 | Characterization of Chlorobium tepidum chlorosomes: a calculation of bacteriochlorophyll c per chlorosome and oligomer modeling. | The bacteriochlorophyll (Bchl) c content and organization was determined for Chlorobium (Cb.) tepidum chlorosomes, the light-harvesting complexes from green photosynthetic bacteria, using fluorescence correlation spectroscopy and atomic force microscopy. Single-chlorosome fluorescence data was analyzed in terms of the ... |
14507705 | Deacylated pulmonary surfactant protein SP-C transforms from alpha-helical to amyloid fibril structure via a pH-dependent mechanism: an infrared structural investigation. | Bovine pulmonary surfactant protein C (SP-C) is a hydrophobic, alpha-helical membrane-associated lipoprotein in which cysteines C4 and C5 are acylated with palmitoyl chains. Recently, it has been found that the alpha-helix form of SP-C is metastable, and under certain circumstances may transform from an alpha-helix to ... |
14507697 | Comparison of the effects of surface tension and osmotic pressure on the interfacial hydration of a fluid phospholipid bilayer. | The effects of three so-called kosmotropic solutes, namely, betaine, sucrose, and choline chloride on 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine large unilamellar vesicles, were studied by measuring the generalized polarization (GP) for the fluorescence emission of the membrane partitioning probe Laurdan. The lat... |
14507696 | Amphotericin B channels in the bacterial membrane: role of sterol and temperature. | Amphotericin B is an antibiotic that forms ion channels in the membrane of a host cell. The change in permeability produced by these channels is greatly improved by sterols; nevertheless, the single channel conductivity remains invariant. Hence, it is proposed that sterols do not act directly, but rather through the mo... |
14507693 | Molecular dynamics investigation of an oriented cyclic peptide nanotube in DMPC bilayers. | Nanotubes resulting from the self-assembly of cyclic peptides formed by eight alpha-amino acids and inserted into lipid bilayers have been shown to function as synthetic, integral transmembrane channels. A nanotube consisting of eight cyclo[(L-Trp-D-Leu)(3)-L-Gln-D-Leu] subunits, organized in an antiparallel, beta-shee... |
14507679 | The effect of chain length on protein solubilization in polymer-based vesicles (polymersomes). | Using a mean-field analysis we derive a consistent model for the perturbation of a symmetric polymeric bilayer due to the incorporation of transmembrane proteins, as a function of the polymer molecular weight and the protein dimensions. We find that the mechanism for the inhibition of protein incorporation in polymeric... |
14507670 | A human-mouse chimera of the alpha3alpha4alpha5(IV) collagen protomer rescues the renal phenotype in Col4a3-/- Alport mice. | Collagen IV is a major structural component of basement membranes. In the glomerular basement membrane (GBM) of the kidney, the alpha3, alpha4, and alpha5(IV) collagen chains form a distinct network that is essential for the long-term stability of the glomerular filtration barrier, and is absent in most patients affect... |
14505406 | The hydroxide complex of Pseudomonas aeruginosa heme oxygenase as a model of the low-spin iron(III) hydroperoxide intermediate in heme catabolism: 13C NMR spectroscopic studies suggest the active participation of the heme in macrocycle hydroxylation. | 13C NMR spectroscopic studies have been conducted with the hydroxide complex of Pseudomonas aeruginosa heme oxygenase (Fe(III)-OH), where OH(-) has been used as a model of the OOH(-) ligand to gain insights regarding the elusive ferric hydroperoxide (Fe(III)-OOH) intermediate in heme catabolism at ambient temperatures.... |
14505405 | Synthesis and self-assembly of a heteroarm star amphiphile with 12 alternating arms and a well-defined core. | We report on a stepwise synthesis of a heteroarm starlike amphiphile containing 12 alternating arms (six polystyrene and six poly(acrylic acid)) connected to a hexabiphenyl aromatic core. The synthesis does not involve polymerization, and only commercially available precursors are used. Most importantly, this amphiphil... |
14505390 | Vibrational coherence from the dipyridine complex of bacteriochlorophyll a: intramolecular modes in the 10-220-cm(-1) regime, intermolecular solvent modes, and relevance to photosynthesis. | We present the first observations of vibrational coherence in the 10-220-cm-1 region from bacteriochlorophyll a (BChl) in solution. A distinction can be made for the first time between BChl's intramolecular normal modes and intermolecular modes between BChl and solvent. The results show that the low-frequency vibration... |
14505386 | Thermally reversible hydrogels via intramolecular folding and consequent self-assembly of a de novo designed peptide. | A small de novo designed peptide (MAX3) is described that exhibits complete thermoreversible self-assembly into a hydrogel network. Importantly, a prerequisite to hydrogelation is that the peptide must first fold into a conformation conducive to self-assembly. At ambient temperature, MAX3 is unfolded, resulting in a lo... |
14499836 | Study on the inclusion complexes of cryptotanshinone with beta-cyclodextrin and hydroxypropyl-beta-cyclodextrin. | The inclusion complexes of beta-cyclodextrin (beta-CD) and HP-beta-cyclodextrin (HP-beta-CD) with a kind of tanshinone, cryptotanshinone (CTan) were investigated by using spectrophotometry. Stable inclusion complexes were established in solution and in solid state and were characterized by UV, IR and 1H NMR spectra, re... |
14499832 | Medium effects on fluorescence of ciprofloxacin hydrochloride. | The medium (pH, organic solvents, cyclodextrin (CD) or surfactants) effects on the fluorescence of ciprofloxacin hydrochloride (CPFX.HCl) were studied in detail. It is found that the three acid constants of ciprofloxacin (CPFX) are near to each other. Therefore the relation curve between pH and fluorescence intensity h... |
14499829 | Study on inclusion complex of cyclodextrin with methyl xanthine derivatives by fluorimetry. | The inclusion complexes of beta-cyclodextrin (beta-CD) and HP-beta-cyclodextrin (HP-beta-CD) with caffeine, theophylline and theobromine were investigated by fluorimetry. Various factors affecting the formation of inclusion complexes were discussed in detail including forming time, pH effect and temperature. The result... |
14501942 | The abdominal compartment syndrome as a second insult during systemic neutrophil priming provokes multiple organ injury. | In our recent clinical study of damage control laparotomy, the abdominal compartment syndrome (ACS) emerged as an independent risk factor for postinjury multiple organ failure (MOF). We and others have shown previously that the ACS promotes the systemic production of proinflammatory cytokines. Our study objective was t... |
14500891 | Binding-induced folding transitions in calpastatin subdomains A and C. | Calpastatin, the endogenous inhibitor of calpain, is an intrinsically unstructured protein proposed to undergo folding transitions upon binding to the enzyme. As this feature has never been experimentally tested, we have set out to characterize the conformation of two peptides corresponding to its conserved subdomains,... |
14500878 | On the structural and functional modularity of glycinamide ribonucleotide formyltransferases. | Glycinamide ribonucleotide formyltransferases (GARTs) are part of the de novo purine biosynthetic pathway, catalyzing the direct transfer of a formyl group from the tetrahydrofolate cofactor to the glycinamide ribonucleotide substrate. Despite the low amino acid-sequence identity between the GARTs from Escherichia coli... |
14500847 | PNA microarrays for hybridisation of unlabelled DNA samples. | Several strategies have been developed for the production of peptide nucleic acid (PNA) microarrays by parallel probe synthesis and selective coupling of full-length molecules. Such microarrays were used for direct detection of the hybridisation of unlabelled DNA by time-of-flight secondary ion mass spectrometry. PNAs ... |
14500838 | dsRBM1 and a proline-rich domain of RNA helicase A can form a composite binder to recognize a specific dsDNA. | The double-stranded RNA-binding motif (dsRBM) is a widely distributed motif frequently found within proteins with sequence non-specific RNA duplex-binding activity. In addition to the binding of double-stranded RNA, some dsRBMs also participate in complex formation via protein-protein interactions. Interestingly, a lot... |
14500834 | In vitro selection of molecular beacons. | While molecular beacons are primarily known as biosensors for the detection of nucleic acids, it has proven possible to adapt other nucleic acid binding species (aptamers) to function in a manner similar to molecular beacons, yielding fluorescent signals only in the presence of a cognate ligand. Unfortunately, engineer... |
14500815 | Characterization of the RNA motif responsible for the specific interaction of potato spindle tuber viroid RNA (PSTVd) and the tomato protein Virp1. | Viroids are small non-coding parasitic RNAs that are able to infect their host plants systemically. This circular naked RNA makes use of host proteins to accomplish its proliferation. Here we analyze the specific binding of the tomato protein Virp1 to the terminal right domain of potato spindle tuber viroid RNA (PSTVd)... |
14502542 | Epimer interconversion, isomerization, and hydrolysis of tetrahydrouridine: implications for cytidine deaminase inhibition. | Tetrahydrouridine (THU) is an inhibitor of cytidine deaminase (CDA), the enzyme responsible for the deactivation of ara-C and other cytidine analogues in vivo, and therefore is capable of improving the therapeutic efficacy of these antitumor agents. In aqueous solution formulations, THU exists as a mixture of epimers d... |
14501494 | Characteristics of a new MRI contrast agent prepared from polypropyleneimine dendrimers, generation 2. | <h4>Rationale and objectives</h4>Dendrimer-based magnetic resonance imaging (MRI) contrast agents offer many advantages including high levels of amplification. The objective of this research was to test the adequacy and viability of a new family of dendrimers for use as MRI contrast agents in vitro and in vivo.<h4>Meth... |
14499473 | Specific interaction of lectins with liposomes and monolayers bearing neoglycolipids. | The interaction of three lectins (wheat germ, Ulex europaeus I, and Lotus tetragonolobus agglutinins: WGA, UEA-I and LTA) with either N-acetyl-D-glucosamine or L-fucose neoglycolipids incorporated into phospholipid monolayers and liposome bilayers was studied at the air/water interface and in bulk solution. The results... |
12852787 | Identification of SNARE complex modulators that inhibit exocytosis from an alpha-helix-constrained combinatorial library. | Synthetic peptides patterned after the proteins involved in vesicle fusion [the so-called SNARE (soluble N -ethylmaleimide-sensitive fusion protein attachment protein receptor) proteins] are potent inhibitors of SNARE complex assembly and neuronal exocytosis. It is noteworthy that the identification of peptide sequence... |
13130131 | Protein synthesis by single ribosomes. | The ribosome is universally responsible for synthesizing proteins by translating the genetic code transcribed in mRNA into an amino acid sequence. Ribosomes use cellular accessory proteins, soluble transfer RNAs, and metabolic energy to accomplish the initiation, elongation, and termination of peptide synthesis. In tra... |
12972333 | Solubilization of Fluasterone in cosolvent/cyclodextrin combinations. | The combined effect of cosolvent (methanol (MeOH), ethanol (EtOH), or n-propanol (n-PrOH)) and complexant hydroxypropyl-beta-cyclodextrin (HP beta CD) on the solubility of Fluasterone is evaluated and explained with a simple equation. The calculated constants in the equation not only quantitatively describe the depende... |
12970437 | Biochemical and genetic characterizations of a novel human immunodeficiency virus type 1 inhibitor that blocks gp120-CD4 interactions. | BMS-378806 is a recently discovered small-molecule human immunodeficiency virus type 1 (HIV-1) attachment inhibitor with good antiviral activity and pharmacokinetic properties. Here, we demonstrate that the compound targets viral entry by inhibiting the binding of the HIV-1 envelope gp120 protein to cellular CD4 recept... |
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