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11967321 | Strength of envelope protein interaction modulates cytopathicity of measles virus. | To understand the molecular determinants of measles virus (MV) cytopathicity, we have characterized mutant viruses exhibiting a more-extensive cell-to-cell fusion while maintaining efficient replication to high titers. A virus which is modified by the addition of an 8-amino-acid Flag epitope tag at the cytoplasmic tail... |
11967318 | Pestivirus internal ribosome entry site (IRES) structure and function: elements in the 5' untranslated region important for IRES function. | The importance of certain structural features of the 5' untranslated region of classical swine fever virus (CSFV) RNA for the function of the internal ribosome entry site (IRES) was investigated by mutagenesis followed by in vitro transcription and translation. Deletions made from the 5' end of the CSFV genome sequence... |
11967317 | Human TATA binding protein inhibits human papillomavirus type 11 DNA replication by antagonizing E1-E2 protein complex formation on the viral origin of replication. | The human papillomavirus (HPV) protein E2 possesses dual roles in the viral life cycle. By interacting directly with host transcription factors in basal keratinocytes, E2 promotes viral transcription. As keratinocyte differentiation progresses, E2 associates with the viral helicase, E1, to activate vegetative viral DNA... |
11967307 | Mechanism of virulence attenuation of glycosaminoglycan-binding variants of Japanese encephalitis virus and Murray Valley encephalitis virus. | The in vivo mechanism for virulence attenuation of laboratory-derived variants of two flaviviruses in the Japanese encephalitis virus (JEV) serocomplex is described. Host cell adaptation of JEV and Murray Valley encephalitis virus (MVE) by serial passage in adenocarcinoma cells selected for variants characterized by (i... |
11967297 | Genetic analysis of cis regulatory elements within the 5' region of the human papillomavirus type 31 upstream regulatory region during different stages of the viral life cycle. | The function of the 5' region of the upstream regulatory region (URR) in regulating E6/E7 expression in cancer-associated papillomaviruses has been largely uncharacterized. In this study we used linker-scanning mutational analysis to identify potential cis regulatory elements contained within a portion of the 5' region... |
11967288 | Human immunodeficiency virus type 1 uses lipid raft-colocalized CD4 and chemokine receptors for productive entry into CD4(+) T cells. | In this report, we describe a crucial role of lipid raft-colocalized receptors in the entry of human immunodeficiency virus type 1 (HIV-1) into CD4(+) T cells. We show that biochemically isolated detergent-resistant fractions have characteristics of lipid rafts. Lipid raft integrity was required for productive HIV-1 en... |
11966979 | Probing degeneracy in antigen-antibody recognition at the immunodominant site of foot-and-mouth disease virus. | Antigen-antibody binding is regarded as one of the most representative examples of specific molecular recognition in nature. The simplistic view of antigenic recognition in terms of a lock-and-key mechanism is obsolete, as it is evident that both antigens and antibodies are flexible and can undergo substantial mutual a... |
11964290 | Constitutive and functional association of the platelet collagen receptor glycoprotein VI-Fc receptor gamma-chain complex with membrane rafts. | The platelet collagen receptor glycoprotein (GP) VI-Fc receptor gamma-chain (FcRgamma) complex transduces signals in an immunoreceptorlike manner. We examined a role for the Triton X-100-insoluble membrane rafts in GPVI-FcRgamma complex signaling. Methyl-beta-cyclodextrin (MbetaCD)-induced disruption of the membrane ra... |
11964262 | Single molecule recognition of protein binding epitopes in brush border membranes by force microscopy. | Sidedness and accessibility of protein epitopes in intact brush border membrane vesicles were analyzed by detecting single molecule interaction forces using molecular recognition force microscopy in aqueous physiological solutions. Frequent antibody-antigen recognition events were observed with a force microscopy tip c... |
11964252 | Nature of Interaction between basic fibroblast growth factor and the antiangiogenic drug 7,7-(carbonyl-bis[imino-N-methyl-4,2-pyrrolecarbonylimino[N-methyl-4,2-pyrrole]-carbonylimino])-bis-(1,3-naphtalene disulfonate). II. Removal of polar interactions affects protein folding. | Fibroblast growth factor-2 (basic FGF), a potent inducer of angiogenesis, and the naphthalene sulfonic distamycin A derivative, 7,7-(carbonyl-bis[imino-N-methyl-4,2-pyrrolecarbonylimino[N-methyl-4,2-pyrrole]-carbonylimino])-bis-(1,3-naphtalene disulfonate) (PNU145156E), which exhibits in vivo antiangiogenic activity, f... |
11964226 | Relating interactions between neurofilaments to the structure of axonal neurofilament distributions through polymer brush models. | Neurofilaments (NFs) have been proposed to interact with one another through mutual steric exclusion of their unstructured C-terminal "sidearm" domains, producing order in axonal NF distributions and conferring mechanical strength to the axon. Here we apply theory developed for polymer brushes to examine the relationsh... |
11964175 | Threonine-124 and phenylalanine-448 in Citrobacter freundii tyrosine phenol-lyase are necessary for activity with L-tyrosine. | Thr-124 and Phe-448 are located in the active site of Citrobacter freundii tyrosine phenol-lyase (TPL) near the phenol ring of a bound substrate analogue, 3-(4'-hydroxyphenyl)propionic acid [Sundararaju, Antson, Phillips, Demidkina, Barbolina, Gollnick, Dodson and Wilson (1997) Biochemistry 36, 6502-6510]. Thr-124 is r... |
11964166 | Subcellular localization of phosphatidylinositol 4,5-bisphosphate using the pleckstrin homology domain of phospholipase C delta1. | Ptd(4,5)P(2) is thought to promote and organize a wide range of cellular functions, including vesicular membrane traffic and cytoskeletal dynamics, by recruiting functional protein complexes to restricted locations in cellular membranes. However, little is known about the distribution of PtdIns(4,5)P(2) in the cell at ... |
11964165 | Metabolic labelling of membrane microdomains/rafts in Jurkat cells indicates the presence of glycerophospholipids implicated in signal transduction by the CD3 T-cell receptor. | Cell membranes contain sphingolipids and cholesterol, which cluster together in distinct domains called rafts. The outer-membrane leaflet of these peculiar membrane domains contains glycosylphosphatidylinositol-anchored proteins, while the inner leaflet contains proteins implicated in signalling, such as the acylated p... |
11964162 | Chicken avidin-related proteins show altered biotin-binding and physico-chemical properties as compared with avidin. | Chicken avidin and bacterial streptavidin are proteins familiar from their use in various (strept)avidin-biotin technological applications. Avidin binds the vitamin biotin with the highest affinity known for non-covalent interactions found in nature. The gene encoding avidin (AVD) has homologues in chicken, named avidi... |
11964158 | Spectroscopic characterization of mutations at the Phe41 position in the distal haem pocket of horseradish peroxidase C: structural and functional consequences. | Three mutants of horseradish peroxidase isoenzyme C (HRPC) have been constructed in which the conserved distal aromatic residue Phe(41) has been substituted by Trp, Val or Ala and the properties of the mutant proteins have been compared with that of the wild-type. The ferric and ferrous states have been studied by reso... |
11964142 | Endolysosomal proteolysis and its regulation. | The endolysosomal system comprises a unique environment for proteolysis, which is regulated in a manner that apparently does not involve protease inhibitors. The system comprises a series of membrane-bound intracellular compartments, within which endocytosed material and redundant cellular components are hydrolysed. En... |
11959573 | In vitro and in vivo antifungal activities of TAK-456, a novel oral triazole with a broad antifungal spectrum. | TAK-456 is a novel oral triazole compound with potent and broad-spectrum in vitro antifungal activity and strong in vivo efficacy against Candida albicans and Aspergillus fumigatus. TAK-456 inhibited sterol synthesis of C. albicans and A. fumigatus by 50% at 3 to 11 ng/ml. TAK-456 showed strong in vitro activity agains... |
11959568 | In vitro and in vivo activities of posaconazole against Coccidioides immitis. | Posaconazole (SCH 56592) was tested against 25 strains of Coccidioides immitis to determine their in vitro susceptibilities. The geometric mean 48-h MIC of posaconazole (POSA) was 0.5 microg/ml, the MIC range was 0.25 to 1 microg/ml, and the MIC at which 50% of the isolates tested are inhibited (MIC50) and the MIC90 we... |
11953421 | Autonomous expression of the slo gene of the bicistronic nga-slo operon of Streptococcus pyogenes. | A recent model for cytolysin-mediated translocation in Streptococcus pyogenes proposes that NAD-glycohydrolase is translocated through streptolysin O-generated pores into a host cell (J. Madden, N. Ruiz, and M. Caparon, Cell 104:143-152, 2001). This model also assumes that the NAD-glycohydrolase (nga) and streptolysin ... |
11953415 | Identification and functional analysis of an immunoreactive DsbA-like thio-disulfide oxidoreductase of Ehrlichia spp. | Novel homologous DsbA-like disulfide bond formation (Dsb) proteins of Ehrlichia chaffeensis and Ehrlichia canis were identified which restored DsbA activity in complemented Escherichia coli dsbA mutants. Recombinant Ehrlichia Dsb (eDsb) proteins were recognized by sera from E. canis-infected dogs but not from E. chaffe... |
11953369 | Receptor-based antidote for diphtheria. | Although equine diphtheria antitoxin may be an effective therapy for human diphtheria, its use often induces serum sickness. We describe here a strategy for developing an alternative treatment based on the human diphtheria toxin (DT) receptor/heparin-binding epidermal growth factor-like growth factor (HB-EGF) precursor... |
11953325 | Host-pathogen interactions: the seduction of molecular cross talk. | Bacterial pathogens have evolved two major strategies to colonise the intestinal epithelium. Adherent microorganisms bind to the apical pole of the intestinal epithelium, whereas invasive microorganisms disrupt and invade the epithelium. Recognition of the genetic bases of bacterial pathogenicity and analysis of the mo... |
11948590 | Rb(+)/Cs(+) selectivity of benzo and tribenzo derivatives of the 21C7 crown ether. A density functional study. | A density functional study has been performed on Rb(+) and Cs(+) complexes of mono and tribenzo derivatives of the 21Crown7 crown ether. Calculations have been carried out using the B3LYP functional together with a split valence basis set with additional polarization and diffuse functions. The cations have been describ... |
11940669 | Interaction between FOG-1 and the corepressor C-terminal binding protein is dispensable for normal erythropoiesis in vivo. | The hematopoietic, zinc-finger protein FOG-1 is essential for the development of the erythroid and megakaryocytic lineages. FOG-1's function in hematopoiesis is dependent on its ability to interact with the transcription factor GATA-1. FOG-1 has also been observed to interact with the corepressor molecule C-terminal bi... |
11940668 | Conserved furin cleavage site not essential for secretion and integration of ZP3 into the extracellular egg coat of transgenic mice. | The extracellular zona pellucida surrounding mammalian eggs is formed by interactions of the ZP1, ZP2, and ZP3 glycoproteins. Female mice lacking ZP2 or ZP3 do not form a stable zona matrix and are sterile. The three zona proteins are synthesized in growing oocytes and secreted prior to incorporation into the zona pell... |
11932429 | Highly stable trimers formed by human immunodeficiency virus type 1 envelope glycoproteins fused with the trimeric motif of T4 bacteriophage fibritin. | The envelope glycoproteins of human immunodeficiency virus type 1 (HIV-1) function as a trimer composed of three gp120 exterior glycoproteins and three gp41 transmembrane proteins. Soluble gp140 glycoproteins composed of the uncleaved ectodomains of gp120 and gp41 form unstable, heterogeneous oligomers, but soluble gp1... |
11932421 | Adeno-associated virus capsids displaying immunoglobulin-binding domains permit antibody-mediated vector retargeting to specific cell surface receptors. | Recombinant adeno-associated virus type 2 (rAAV2) is a promising vector for human somatic gene therapy. However, its broad host range is a disadvantage for some applications, because it reduces the specificity of the gene transfer. To overcome this limitation, we sought to create a versatile rAAV vector targeting syste... |
11932408 | Novel strategy for inhibiting viral entry by use of a cellular receptor-plant virus chimera. | The plant virus cowpea mosaic virus (CPMV) has recently been developed as a biomolecular platform to display heterologous peptide sequences. Such CPMV-peptide chimeras can be easily and inexpensively produced in large quantities from experimentally infected plants. This study utilized the CPMV chimera platform to creat... |
11932396 | Pit2 assemblies at the cell surface are modulated by extracellular inorganic phosphate concentration. | Pit2 is a type III sodium-dependent phosphate transporter and the cell surface receptor for amphotropic murine leukemia virus. Indirect arguments have previously suggested that retrovirus receptor assembly play a role in triggering membrane fusion. Using CHO cells expressing physiological amounts of functional versions... |
11891133 | Changes in protease activity and Cry3Aa toxin binding in the Colorado potato beetle: implications for insect resistance to Bacillus thuringiensis toxins. | Widespread commercial use of Bacillus thuringiensis Cry toxins to control pest insects has increased the likelihood for development of insect resistance to this entomopathogen. In this study, we investigated protease activity profiles and toxin-binding capacities in the midgut of a strain of Colorado potato beetle (CPB... |
11886791 | Novel irreversible butyrylcholinesterase inhibitors: 2-chloro-1-(substituted-phenyl)ethylphosphonic acids. | 2-Chloroethylphosphonic acid (ethephon) as the dianion phosphorylates butyrylcholinesterase (BChE) at its active site. In contrast, the classical organophosphorus esterase inhibitors include substituted-phenyl dialkylphosphates (e.g., paraoxon) with electron-withdrawing aryl substituents. The chloroethyl and substitute... |
11821128 | Scorpion toxins from Tityus cambridgei that affect Na(+)-channels. | By means of high performance liquid chromatography (HPLC) the soluble venom of the Amazonian scorpion Tityus cambridgei was fractionated into over 50 different components. Four toxic and/or lethal peptides to mice were obtained in pure form and sequenced. Mass spectrometry analysis showed molecular weights of 7310, 715... |
12107686 | The tyrosine kinase inhibitor tyrphostin AG 126 reduces the multiple organ failure induced by zymosan in the rat. | <h4>Objective</h4>To investigate the effects of tyrphostin AG 126, a tyrosine kinase inhibitor, on the multiple organ failure (MOF) caused by zymosan in the rat.<h4>Design</h4>Zymosan (500 mg/kg, suspended in saline solution, i.p.) causes an enhanced formation of reactive oxygen species, which contribute to the pathoph... |
12049668 | The diversity of acetylated proteins. | Acetylation of proteins, either on various amino-terminal residues or on the epsilon-amino group of lysine residues, is catalyzed by a wide range of acetyltransferases. Amino-terminal acetylation occurs on the bulk of eukaryotic proteins and on regulatory peptides, whereas lysine acetylation occurs at different positio... |
11983867 | Dynamic assembly of MinD on phospholipid vesicles regulated by ATP and MinE. | Selection of the division site in Escherichia coli is regulated by the min system and requires the rapid oscillation of MinD between the two halves of the cell under the control of MinE. In this study we have further investigated the molecular basis for this oscillation by examining the interaction of MinD with phospho... |
11983859 | Aldosterone signaling pathway across the nuclear envelope. | We describe the route by which aldosterone-triggered macromolecules enter and exit the cell nucleus of Xenopus laevis oocyte. Oocytes were microinjected with 50 fmol aldosterone and then enucleated 2-30 min after injection. After isolation, nuclear envelope electrical resistance (NEER) was measured in the intact cell n... |
11983858 | Epidermolysis bullosa and embryonic lethality in mice lacking the multi-PDZ domain protein GRIP1. | Glutamate receptor-interacting protein 1 (GRIP1) is an adaptor protein composed of seven PDZ (postsynaptic density-95/Discs large/zona occludens-1) domains, capable of mediating diverse protein-protein interactions. GRIP1 has been implicated in the regulation of neuronal synaptic function, but its physiologic roles hav... |
11983999 | The molecular and supramolecular structures of four 1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazolines. | The supramolecular structures of the title compounds, 2-phenyl-5-p-tolyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(23)H(21)N(3), (I), 5-(4-bromophenyl)-2-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(22)H(18)BrN(3), (II), 2-(4-chlorophenyl)-5-phenyl-1,5,6,10b-tetrahydropyrazolo[1,5-c]quinazoline, C(2... |
11983997 | C-H...pi and pi--pi interactions in the supramolecular structure of 3-methyl-1,4-diphenyl-1H-pyrazolo[3,4-b]pyridine. | The supramolecular structure of the title compound, C(19)H(15)N(3), is defined by pi-pi-stacking and C-H.pi interactions. There are no conventional hydrogen bonds in the structure. |
11980923 | Cosignaling of NCAM via lipid rafts and the FGF receptor is required for neuritogenesis. | The neural cell adhesion molecule (NCAM) has been reported to stimulate neuritogenesis either via nonreceptor tyrosine kinases or fibroblast growth factor (FGF) receptor. Here we show that lipid raft association of NCAM is crucial for activation of the nonreceptor tyrosine kinase pathway and induction of neurite outgro... |
31903048 | Emission Spectral Properties of Cadmium Sulfide Nanoparticles with Multiphoton Excitation. | We describe the luminescence spectral properties of CdS nanoparticles with multiphoton excitation. Three types of CdS nanoparticles were examined which were a CdS/dendrimer composite which displays high anisotropy, Cd<sup>2+</sup>-enriched nanoparticles which display two emission maxima, and polyphosphate-stabilized na... |
11976335 | Hypercholesterolemia promotes a CD36-dependent and endothelial nitric-oxide synthase-mediated vascular dysfunction. | Numerous studies have implicated either the presence or absence of CD36 in the development of hypertension. In addition, hypercholesterolemia is associated with the loss of nitric oxide-induced vasodilation and the subsequent increase in blood pressure. In the current study, we tested the hypothesis that diet-induced h... |
11972320 | Homology induction: the use of machine learning to improve sequence similarity searches. | <h4>Background</h4>The inference of homology between proteins is a key problem in molecular biology The current best approaches only identify approximately 50% of homologies (with a false positive rate set at 1/1000).<h4>Results</h4>We present Homology Induction (HI), a new approach to inferring homology. HI uses machi... |
11972031 | Chiral protein scissors: high enantiomeric selectivity for binding and its effect on protein photocleavage efficiency and specificity. | Chiral recognition of protein-binding sites by a simple organic molecule with selectivities >100 is reported here. The l-isomer of 4(1-pyrene)-3-butyroyl-phenylalanine amide (Py-L-Phe) binds to BSA with an affinity constant (K(b)) of 3 x 10(7) M(-1), whereas the corresponding D-isomer (Py-D-Phe) binds 100 times weaker.... |
11972026 | A dynamic shift of VEGF isoforms with a transient and selective progesterone-induced expression of VEGF189 regulates angiogenesis and vascular permeability in human uterus. | A key mechanism underlying physiological angiogenesis of the human endometrium is its ability to regenerate the vascular capillary network and to perform vascular remodeling (i.e., development of spiral arteries). Vascular endothelial growth factor (VEGF) is associated with angiogenesis and capillary permeability in th... |
12052253 | CCAAT/enhancer binding proteins in normal mammary development and breast cancer. | CCAAT/enhancer binding proteins (C/EBPs) are a family of leucine zipper, transcription factors that bind to DNA as homodimers and heterodimers. They regulate cellular proliferation, differentiation and apoptosis in the mammary gland. Multiple protein isoforms, including truncated, dominant negatives, are generated by t... |
12005694 | Microscopic formation mechanism of nanotube peapods. | Using molecular dynamics calculations, we investigate the absorption of a C(60) molecule in a (10,10) nanotube either through the open end or a large defect in the tube wall as possible scenarios for the hierarchical self-assembly of (C(60))(n)@(10,10) "nano-peapods." We find the absorption through a defect to be signi... |
11964385 | Spontaneous insertion and partitioning of alkaline phosphatase into model lipid rafts. | Several cell surface eukaryotic proteins have a glycosylphosphatidylinositol (GPI) modification at the C-terminal end that serves as an anchor to the plasma membrane and could be responsible for the presence of GPI proteins in rafts, a type of functionally important membrane microdomain enriched in sphingolipids and ch... |
11960978 | Evidence for a transition state analog, MgADP-aluminum fluoride-acetate, in acetate kinase from Methanosarcina thermophila. | Aluminum fluoride has become an important tool for investigating the mechanism of phosphoryl transfer, an essential reaction that controls a host of vital cell functions. Planar AlF(3) or AlF(4)(-) molecules are proposed to mimic the phosphoryl group in the catalytic transition state. Acetate kinase catalyzes phosphory... |
11959907 | Segmented nanofibers of spider dragline silk: atomic force microscopy and single-molecule force spectroscopy. | Despite its remarkable materials properties, the structure of spider dragline silk has remained unsolved. Results from two probe microscopy techniques provide new insights into the structure of spider dragline silk. A soluble synthetic protein from dragline silk spontaneously forms nanofibers, as observed by atomic for... |
12049667 | Beyond the proteome: non-coding regulatory RNAs. | A variety of RNA molecules have been found over the last 20 years to have a remarkable range of functions beyond the well-known roles of messenger, ribosomal and transfer RNAs. Here, we present a general categorization of all non-coding RNAs and briefly discuss the ones that affect transcription, translation and protei... |
11956232 | Overexpression of the myelin proteolipid protein leads to accumulation of cholesterol and proteolipid protein in endosomes/lysosomes: implications for Pelizaeus-Merzbacher disease. | Duplications and overexpression of the proteolipid protein (PLP) gene are known to cause the dysmyelinating disorder Pelizaeus-Merzbacher disease (PMD). To understand the cellular response to overexpressed PLP in PMD, we have overexpressed PLP in BHK cells and primary cultures of oligodendrocytes with the Semliki Fores... |
11956229 | Specific SHP-2 partitioning in raft domains triggers integrin-mediated signaling via Rho activation. | Cell signaling does not occur randomly over the cell surface, but is integrated within cholesterol-enriched membrane domains, termed rafts. By targeting SHP-2 to raft domains or to a non-raft plasma membrane fraction, we studied the functional role of rafts in signaling. Serum-depleted, nonattached cells expressing the... |
11956228 | Translocation of PKC[theta] in T cells is mediated by a nonconventional, PI3-K- and Vav-dependent pathway, but does not absolutely require phospholipase C. | PKCtheta plays an essential role in activation of mature T cells via stimulation of AP-1 and NF-kappaB, and is known to selectively translocate to the immunological synapse in antigen-stimulated T cells. Recently, we reported that a Vav/Rac pathway which depends on actin cytoskeleton reorganization mediates selective r... |
11943875 | Organization of the interior of molecular capsules by hydrogen bonding. | The enclosure of functional entities within a protective boundary is an essential feature of biological systems. On a molecular scale, free-standing capsules with an internal volume sufficiently large to house molecular species have been synthesized and studied for more than a decade. These capsules have been prepared ... |
11943874 | Probing alkali metal-pi interactions with the side chain residue of tryptophan. | Feeble forces play a significant role in the organization of proteins. These include hydrogen bonding, hydrophobic interactions, salt bridge formation, and steric interactions. The alkali metal cation-pi interaction is a force of potentially profound importance but its consideration in biology has been limited by the l... |
11943873 | Cooperative anion binding and electrochemical sensing by modular podands. | A series of podands based on two or three hydrogen bonding "arms" situated in mutually ortho, meta, or para relationships about an aryl core have been prepared, and their affinities for simple inorganic anions were measured. Of the two-arm hosts the meta compound and to a lesser extent the ortho host exhibit a cooperat... |
11943871 | A Kaposi's sarcoma-associated herpesviral protein inhibits virus-mediated induction of type I interferon by blocking IRF-7 phosphorylation and nuclear accumulation. | Interferons constitute the earliest immune response against viral infection. They elicit antiviral effects as well as multiple biological responses involved in cell growth regulation and immune activation. Because the interferon-induced cellular antiviral response is the primary defense mechanism against viral infectio... |
11943865 | Dynamic chemical devices: modulation of contraction/extension molecular motion by coupled-ion binding/pH change-induced structural switching. | Dynamic chemical devices involve morphological or constitutional modifications in molecular or supramolecular systems, induced by internal or external physical or chemical triggers. Reversible changes in shape result in molecular motions and define motional dynamic devices presenting mechanical-like actions of various ... |
11943861 | Threefold symmetric trimetallic macrocycles formed via the Weak-Link Approach. | The synthesis and characterization of a new threefold symmetric hemilabile phosphino-alkylthioether ligand are described. This ligand can be used in combination with Rh(I) and Ir(I) precursor complexes to prepare 40-membered macrocyles with threefold symmetry via the Weak-Link Approach. Synthesis and characterization o... |
11943858 | Chiral discrimination in cyclodextrin complexes of amino acid derivatives: beta-cyclodextrin/N-acetyl-L-phenylalanine and N-acetyl-D-phenylalanine complexes. | In a systematic study of molecular recognition of amino acid derivatives in solid-state beta-cyclodextrin (beta-CD) complexes, we have determined crystal structures for complexes of beta-cyclodextrin/N-acetyl-L-phenylalanine at 298 and 20 K and for N-acetyl-D-phenylalanine at 298 K. The crystal structures for the N-ace... |
11943857 | A peptide template as an allosteric supramolecular catalyst for the cleavage of phosphate esters. | The heptapeptide H-Iva-Api-Iva-ATANP-Iva-Api-Iva-NHCH(3) (P1a), where Iva is (S)-isovaline, Api is 4-amino-4-carboxypiperidine, and ATANP is (S)-2-amino-3-[1-(1,4,7-triazacyclononane)]propanoic acid, has been synthesized. Its conformation in aqueous solution is essentially that of a 3(10)-helix. By connecting three cop... |
11943856 | Design and self-assembly of wide and robust coordination cages. | The self-assembly of a new class of coordination cages formed from two tetrapyridyl-substituted cavitands connected through four square-planar palladium or platinum complexes is reported. The shape of the internal cavity resembles an ellipsoid with a calculated volume of 840 A(3). The four lateral portals have a diamet... |
11943855 | Extending supramolecular fullerene-porphyrin chemistry to pillared metal-organic frameworks. | Porphyrins and fullerenes are spontaneously attracted to each other. This supramolecular recognition element can be exploited to produce ordered arrays of interleaved porphyrins and fullerenes. C(60) x H(2)TpyP x Pb(NO(3))(2) x 1.5TCE (H(2)TpyP = tetra-4-pyridylporphyrin; TCE = 1,1,2,2-tetrachloroethane) crystallizes i... |
11943851 | Partial shell-filled core-shell tecto(dendrimers): a strategy to surface differentiated nano-clefts and cusps. | Poly(amidoamine) (PAMAM) dendrimer shell reagents possessing either nucleophilic (i.e., primary amines) or electrophilic (i.e., carboxymethyl esters) functional groups have been covalently assembled around appropriate electrophilic or nucleophilic dendrimer core reagents to produce partial shell filled/core-shell tecto... |
11943850 | Self-organization of self-assembled photonic materials into functional devices: photo-switched conductors. | Linear porphyrin arrays self-assembled by either hydrogen bonding or metal ion coordination self-organize into lipid bilayer membranes. The length of the transmembrane assemblies is determined both by the thermodynamics of the intermolecular interactions in the supermolecule and by the dimension and physical chemical p... |
11943849 | Conformation and anion binding properties of cyclic hexapeptides containing L-4-hydroxyproline and 6-aminopicolinic acid subunits. | Two cyclic hexapeptides containing alternating all R and all S configured Ll-(4R/S)-hydroxyproline and 6-aminopicolinic acid subunits are presented, and the influence of the hydroxyl groups on the solubility, conformation, and receptor properties is investigated. Cyclopeptide 2, containing the natural 4R configured hyd... |
12203013 | Interaction between a DNA oligonucleotide and a dinuclear iron(II) supramolecular cylinder; an NMR and molecular dynamics study. | A tetracationic supramolecular cylinder, [Fe(2)L(3)](4+) (L=C(25)H(20)N(4)), with a triple-helical architecture, is just the right size to fit into the major groove of DNA but too big to fit into the minor groove. A detailed NMR spectroscopic analysis supported by molecular dynamics (MD) calculations shows unambiguousl... |
11929986 | Inhibition of chymotrypsin through surface binding using nanoparticle-based receptors. | Efficient binding of biomacromolecular surfaces by synthetic systems requires the effective presentation of complementary elements over large surface areas. We demonstrate here the use of mixed monolayer protected gold clusters (MMPCs) as scaffolds for the binding and inhibition of chymotrypsin. In these studies anioni... |
11929983 | Catalysis of cis/trans isomerization in native HIV-1 capsid by human cyclophilin A. | Packaging of cyclophilin A (CypA) into HIV-1 virions is essential for efficient replication; however, the reason for this is unknown. Incorporation is mediated through binding to the Gly-89-Pro-90 peptide bond of the N-terminal domain of HIV-1 capsid (CA(N)). Despite the fact that CypA is a peptidyl-prolyl cis/trans is... |
11929981 | Peptide-amphiphile nanofibers: a versatile scaffold for the preparation of self-assembling materials. | Twelve derivatives of peptide-amphiphile molecules, designed to self-assemble into nanofibers, are described. The scope of amino acid selection and alkyl tail modification in the peptide-amphiphile molecules are investigated, yielding nanofibers varying in morphology, surface chemistry, and potential bioactivity. The r... |
11929980 | Unraveling the nanostructure of supramolecular assemblies of hydrogen-bonded rosettes on graphite: an atomic force microscopy study. | The self-organization of multicomponent tetrarosette assemblies into ordered nanostructures on graphite surfaces has been studied by atomic force microscopy (AFM). Real-space information on the level of individual molecules allowed us to analyze the underlying structure in unprecedented detail. In highly ordered nanoro... |
11929979 | Self-organizing super-structures formed from hydrogen-bonded biimidazolate metal complexes. | Manipulation of molecular crystals formed from self-organization is one of the important methods to develop the new molecular functional materials. In particular, we look upon mutual cohesive interactions of hydrogen bonding and metal coordination as one useful tool to construct the preprogramming superstructures. In t... |
11929978 | Hierarchical formation of helical supramolecular polymers via stacking of hydrogen-bonded pairs in water. | Bifunctional ureido-s-triazines provided with penta(ethylene oxide) side chains are able to self assemble in water, leading to helical columns via cooperative stacking of the hydrogen-bonded pairs (DADA array). Monofunctional ureido-s-triazines do not form such helical architectures. The presence of a linker, covalentl... |
11929976 | Configurationally homogeneous diastereomers of a linear hexa(tertiary phosphine): enantioselective self-assembly of a double-stranded parallel helicate of the type (P)-[Cu(3)(hexaphos)(2)](PF(6))(3). | Three configurationally homogeneous diastereomers of the linear hexa(tertiary phosphine) Ph(2)PCH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)P(Ph)CH(2)CH(2)PPh(2) (hexaphos) have been isolated in enantiomerically pure form, namely (R,S,S,R)-, (R,S,S,S)-, and (S,S,S,S)-hexaphos. The strongly helicating (R,S,S,R... |
11929973 | Molecular self-assembly of surfactant-like peptides to form nanotubes and nanovesicles. | Several surfactant-like peptides undergo self-assembly to form nanotubes and nanovesicles having an average diameter of 30-50 nm with a helical twist. The peptide monomer contains 7-8 residues and has a hydrophilic head composed of aspartic acid and a tail of hydrophobic amino acids such as alanine, valine, or leucine.... |
11929969 | Unidirectional rotary motion in a liquid crystalline environment: color tuning by a molecular motor. | Life could not exist without motion induced by a variety of molecular motors. The construction of artificial motors by chemical synthesis, which can power motions that lead to macroscopic detectable effects in a system, is a major endeavor in contemporary science. To move toward this goal, a host-guest system, composed... |
11929968 | Self-assembly directed by NH...O hydrogen bonding: new layered molecular arrays derived from 4-tert- butylbenzoic acid and aliphatic diamines. | (1H) and (13)C NMR titrations in both CDCl(3) and CD(3)OD demonstrate that 4-tert-butylbenzoic acid interacts with both propane-1,2-diamine and propane-1,3-diamine to yield 1:2 host-guest complexes in these solvents. Based on this observation, the isolation of new three-dimensional molecular arrays through cocrystalliz... |
11929967 | Cytosine substituted calix[4]pyrroles: neutral receptors for 5'-guanosine monophosphate. | The synthesis and characterization of two cytosine-substituted calix[4]pyrrole conjugates, bearing the appended cytosine attached at either a beta- or meso-pyrrolic position, is described. These systems were tested as nucleotide-selective carriers and as active components of nucleotide-sensing ion-selective electrodes ... |
11929965 | Phase transfer of monosaccharides through noncovalent interactions: selective extraction of glucose by a lipophilic cage receptor. | We have previously shown that macrotricyclic host 1a is a powerful receptor for glucopyranosyl units in the nonpolar medium of chloroform. However, the solubility properties of 1a did not permit studies of the extraction of carbohydrates from aqueous solution. This paper describes the synthesis of the new variant 1b, f... |
11929964 | Pillared honeycomb nanoarchitectures formed on solid surfaces by the self-assembly of lipid-packaged one-dimensional Pt complexes. | A highly lipophilic polyion complex [Pt(en)(2)][PtCl(2)(en)(2)](1)(4) (en, 1,2-diaminoethane) is prepared from one-dimensional mixed valence Pt(II)/Pt(IV) complex and newly designed chiral amphiphile 1. The powdery sample showed purple color, which is a result of the mixed valence absorption of the linear chlorobridged... |
11929963 | Chemically induced supramolecular reorganization of triblock copolymer assemblies: trapping of intermediate states via a shell-crosslinking methodology. | The mechanism of morphological phase transitions was studied for rod-shaped supramolecular assemblies comprised of a poly(acrylic acid)-block-poly(methyl acrylate)-block-polystyrene (PAA(90)-b-PMA(80)-b-PS(100)) triblock copolymer in 33% tetrahydrofuran/water after perturbation by reaction with a positively charged wat... |
11929962 | Anion-templated self-assembly of tetrahedral cage complexes of cobalt(II) with bridging ligands containing two bidentate pyrazolyl-pyridine binding sites. | The bridging ligands L(1) and L(2) contain two N,N-bidentate pyrazolyl-pyridine units linked to a central aromatic spacer unit (1,2-phenyl or 2,3-naphthyl, respectively). Reaction with Ni(II) salts and treatment with the anions tetrafluoroborate or perchlorate result in formation of dinuclear complexes having a 2:3 met... |
19750755 | Dendritic polymers in biomedical applications: from potential to clinical use in diagnostics and therapy. | Dendrimers are characterized by a combination of high end-group functionality and a compact, precisely defined molecular structure. These characteristics can be used in biomedical applications, for example, for the amplification or multiplication of effects on a molecular level, or to create extremely high local concen... |
16902667 | Innervation of the anterior spinal canal: an update. | Understanding the innervation of the lumbar spine can be a daunting task. Until recently, only macroscopic visualization and crude histological techniques were available to document the presence of nerve fibers in the anterior spinal canal. Using newer immunohistochemical techniques, studies have been able to more thor... |
16290555 | Physicochemical properties of quaternized poly(amidoamine) dendrimers with alkyl groups and of their mixtures with sodium dodecyl sulfate. | The physicochemical properties of quaternized poly(amidoamine) dendrimers (generation 4) with methyl or octyl groups and of their mixtures with sodium dodecyl sulfate (SDS) in aqueous solutions have been investigated using several techniques including surface tension, fluorescence of pyrene, and dynamic light scatterin... |
11988405 | The Syrian golden hamster strain LPN: a useful animal model for human cholelithiasis. | The purpose of this study was to specify the main mechanisms at the origin of gallstone formation in very young (5-week old) or young adult (9-week old) LPN hamsters fed a sucrose-rich (normal lipid) lithogenic diet for one and four weeks, respectively. It was also to compare these mechanisms in the two strains of hams... |
11988404 | Metallothionein mRNA levels are influenced by dietary cyclodextrins in rats. | The relationship between metallothionein mRNA levels and the amounts of copper and zinc in liver, kidney and small intestine by feeding dietary cyclodextrin was examined in growing Wistar rats. alpha-, beta- or gamma-cyclodextrin was fed at 50 g/kg of diet for a 7-days period (ad libitum). After feeding, the liver zinc... |
12908300 | Self-assembled nanocomposite of organic-inorganic hybrid: 2,4-dichlorophenoxyacetate in Zn-Al hydrotalcite-like layers. | Hydrotalcite-like inorganic layers of Zn-Al, a host containing an organic moiety, 2,4-dichlorophenoxy-acetate, as a guest, was prepared by the spontaneous self-assembly method from an aqueous solution for the formation of a new layered organic-inorganic hybrid nanocomposite material. In this synthesis, the host- and gu... |
12908297 | Nanoencapsulation of [60] fullerene by a novel sugar-based polymer. | [60] Fullerene has been nanoencapsulated by the formation of an inclusion complex with a beta-cyclodextrin-containing lactose copolymer. The cyclodextrin polymer was synthesized by reaction of beta-cyclodextrin chlorotriazine with beta-lactose, and the polymer was highly soluble in water. Encapsulation of the carbon al... |
12491241 | Chirality of living systems: a helping hand from crystals and oligopeptides. | Left-right asymmetry is ubiquitous in nature. Recent studies reveal changes in the energy and growth rate of crystal surfaces to which D or L amino acids bind, with the binding itself being dictated by stereochemical matching. Likewise, oligomerization of amino acids appears to be a chiroselective process that enables ... |
12380688 | Activation of the mitogen-activated protein kinase pathways by heat shock. | In addition to inducing new transcriptional activities that lead within a few hours to the accumulation of heat shock proteins (Hsps), heat shock activates within minutes the major signaling transduction pathways involving mitogen-activated protein kinases, extracellular signal-regulated kinase, stress-activated protei... |
12380682 | Distribution, phosphorylation, and activities of Hsp25 in heat-stressed H9c2 myoblasts: a functional link to cytoprotection. | The behavior of the endogenous heat shock protein 25 (Hsp25) in heat-stressed rat H9c2 myoblasts was studied. After mild or severe heating, this protein became less extractable with Triton X-100 and displayed characteristic immunofluorescence patterns, namely (1) granules in the nucleus, and (2) association with F-acti... |
12194050 | Use of dicyclohexano-18-crown-6 to separate traces of silver(I) from potassium thiocyanate in hydrochloric acid media, and determination of the silver by atomic absorption spectrometry. | Solvent extraction with 0.05 mol L(-1) dicyclohexano-18-crown-6 (DC18C6) in 1,2-dichloroethane, coupled with flame atomic absorption spectrometry (AAS), has been investigated as a new method for separation of trace amounts of silver(I) from 0.05 mol L(-1) potassium thiocyanate in 1.0 mol L(-1) hydrochloric acid media a... |
12194031 | Properties of glucose biosensors based on dendrimer layers. Effect of enzyme immobilization. | The properties of glucose biosensors based on dendrimer layers on a gold support, which depend on the method of immobilization of glucose oxidase (GOX), were studied by amperometry. The kinetic parameters of enzymatic reactions, response time, sensitivity, detection limit, linear range, and enzyme turnover were determi... |
12194030 | Charge mediation by ruthenium poly(pyridine) complexes in 'second-generation' glucose biosensors based on carboxymethylated beta-cyclodextrin polymer membranes. | Four different poly(pyridine) complexes of ruthenium, viz. Ru(II)(trpy)(phen)(OH(2))](2+) (1), trans-[Ru(III)(2,2'bpy)(2)(OH(2))(OH)](2+) (2), [(2,2'bpy)(2)(OH)Ru(III)ORu(III)(OH)(2,2'bpy)(2)](4+) (3), and [Ru(II)(4,4'bpy)(NH(3))(5)](2+) (4) (2,2'bpy=2,2'-bipyridine, 4,4'bpy=4,4'-bipyridine, trpy=2,2',2"-terpyridine, p... |
12141910 | Presence of distinct virtual backbone torsion angles in dipeptide conformers. | Zwitterionic dipeptides have recently been shown to exist in water mainly as nine conformational forms with specific combinations of backbone Psi, omega and Phi torsions, which allows conformer-specific molecular recognition of peptide ligands by proteins. Here, we show that pairs of virtual backbone torsions can also ... |
12123040 | Formation of A2B2 supramolecular porphyrin co-polymers. | New supramolecular A2B2 co-polymers formed in solution from a rigid diporphyrin monomer (the A2 unit) and a short flexible dipyridine monomer (the B2 unit) are reported; NMR experiments show that complete binding occurs at mM concentrations; UV titrations reveal that the dipyridine unit and a monomeric control ligand h... |
12123033 | The first structurally characterized cationic lanthanide-alkyl complexes. | Reaction of rare earth metal-alkyl complexes [Ln(CH2SiMe3)3(THF)2](Ln = Y, Lu) with B(C6X5)3(X = H, F) in the presence of crown ethers gives crystallographically characterized ion pairs [Ln(CH2SiMe3)2(CE)(THF)n]+[B(CH2SiMe3)(C6X5)3]-(CE = [12]-crown-4, n = 1; CE = [15]-crown-5 and [18]-crown-6, n = 0). |
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