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12954055 | Synthesis and discovery of macrocyclic polyoxygenated bis-7-azaindolylmaleimides as a novel series of potent and highly selective glycogen synthase kinase-3beta inhibitors. | Attempts to design the macrocyclic maleimides as selective protein kinase C gamma inhibitors led to the unexpected discovery of a novel series of potent and highly selective glycogen synthase kinase-3beta (GSK-3beta) inhibitors. Palladium-catalyzed cross-coupling reactions were used to synthesize the key intermediates ... |
12954192 | The effect of beta-cyclodextrins on the permeation of diclofenac from supersaturated solutions. | Supersaturation is a very useful method of enhancing the permeation of drugs across membranes such as skin, because unlike other methods, it does not interfere with the ultrastructure of the stratum corneum. Many drugs are able to form inclusion complexes with beta-cyclodextrins (beta-CDs) and this study investigates t... |
12954184 | Safety-assessment of 3-methoxyquercetin as an antirhinoviral compound for nasal application: effect on ciliary beat frequency. | It has been shown that 5,7,3',4'-tetrahydroxy-3-O-methylflavone (3-MQ) exhibits antipicornaviral activity. In order to explore the potential of 3-MQ as an antirhinoviral compound for nasal application, the effect of 3-MQ on the ciliary beat frequency (CBF) of human nasal epithelial cells was studied in vitro in the abs... |
12837133 | Different modes of internalization of apoptotic alkyl-lysophospholipid and cell-rescuing lysophosphatidylcholine. | The synthetic alkyl-lysophospholipid (ALP), Et-18-OCH3 (1-O-octadecyl-2-O-methyl-rac-glycero-3-phosphocholine), can induce apoptosis in tumour cells. Unlike conventional chemotherapeutic drugs, ALP acts at the cell-membrane level. We have reported previously that ALP is internalized, and interferes with phosphatidylcho... |
12803543 | RecQ helicases: suppressors of tumorigenesis and premature aging. | The RecQ helicases represent a subfamily of DNA helicases that are highly conserved in evolution. Loss of RecQ helicase function leads to a breakdown in the maintenance of genome integrity, in particular hyper-recombination. Germ-line defects in three of the five known human RecQ helicases give rise to defined genetic ... |
12952908 | Sequence-specific modification of genomic DNA by small DNA fragments. | Small DNA fragments have been used to modify endogenous genomic DNA in both human and mouse cells. This strategy for sequence-specific modification or genomic editing, known as small-fragment homologous replacement (SFHR), has yet to be characterized in terms of its underlying mechanisms. Genotypic and phenotypic analy... |
12952478 | Studies into the thermodynamic origin of negative cooperativity in ion-pairing molecular recognition. | The association of synthetic receptors to target guests often proceeds through the cooperative action of multiple binding forces. An investigation into the thermodynamic origin of cooperativity in ion-pairing host-guest binding in water is described. The binding affinities of 1,2,3,4-butanetetracarboxylate, tricarballa... |
12952440 | Long-range magnetic coupling through extended pi-conjugated aromatic bridges in dinuclear copper(II) metallacyclophanes. | Self-assembly of 1,4-phenylenebis(oxamate) and 4,4'-biphenylenebis(oxamate) ligands and Cu2+ ions gives two new dinuclear copper(II) metallacyclophanes where the two metal centers are connected by double para-substituted aromatic diamide bridges. Despite the relatively large intramolecular Cu-Cu distance of ca. 8 and 1... |
12953210 | Templated synthesis of a rotaxane with a [Ru(diimine)3]2+ core. | A rotaxane containing a ruthenium bisphenanthroline complex, acting as an axis, and a macrocycle incorporating a 2,2'-bipyridine (bpy) unit, threaded by the axis, has been synthesized. The bisphenanthroline ligand is such that its ruthenium(II) complexes possess a clearly identified axis, making such compounds ideal co... |
12953207 | Helical supramolecular aggregates based on ureidopyrimidinone quadruple hydrogen bonding. | A series of mono- and bifunctional compounds 2-7, based on the ureido pyrimidinone quadruple hydrogen bonding unit, was prepared to study the mode of aggregation of these compounds in the bulk and in solution. Compounds 2-7 exhibit thermotropic liquid crystalline properties, as evidenced by differential scanning calori... |
12953190 | Kinetic versus thermodynamic control during the formation of [2]rotaxanes by a dynamic template-directed clipping process. | A template-directed dynamic clipping procedure has generated a library of nine [2]rotaxanes that have been formed from three dialkylammonium salts-acting as the dumbbell-shaped components-and three dynamic, imino bond-containing, [24]crown-8-like macrocycles-acting as the ring-shaped components-which are themselves ass... |
12953187 | Synthesis, X-ray crystal structure, UV/visible linear and nonlinear (optical limiting) spectral properties of symmetrical and unsymmetrical porphyrazines with annulated 1,2,5-thiadiazole and 1,4-diamyloxybenzene moieties. | Co-cyclization of 1,2,5-thiadiazole-3,4-dicarbonitrile and 3,6-diamyloxyphthalodinitrile in the presence of magnesium or lithium amylate in amyl alcohol leads to mixtures containing the Mg derivatives of the symmetrical species tetrakis(1,2,5-thiadiazolo)porphyrazine, (S(4))PzH(2), and tetrakis(1,4-diamyloxybenzo)porph... |
12951599 | Molecular biomimetics: nanotechnology through biology. | Proteins, through their unique and specific interactions with other macromolecules and inorganics, control structures and functions of all biological hard and soft tissues in organisms. Molecular biomimetics is an emerging field in which hybrid technologies are developed by using the tools of molecular biology and nano... |
12950931 | VirE2, a type IV secretion substrate, interacts with the VirD4 transfer protein at cell poles of Agrobacterium tumefaciens. | Agrobacterium tumefaciens transfers oncogenic DNA and effector proteins to plant cells during the course of infection. Substrate translocation across the bacterial cell envelope is mediated by a type IV secretion (TFS) system composed of the VirB proteins, as well as VirD4, a member of a large family of inner membrane ... |
12950928 | A supramolecular complex in the environmental stress signalling pathway of Bacillus subtilis. | SigmaB, an alternative sigma-factor of Bacillus subtilis, mediates the response of the cell to a variety of physical insults. Within the environmental stress signalling pathway RsbU, a protein phosphatase, is stimulated by its interaction with the protein kinase RsbT. In the absence of stress RsbT is expected to be tra... |
12950225 | UV photostability of metal phthalocyanines in organic solvents. | Kinetic studies of photochemical reactions induced by UV radiation in solutions of metal phthalocyanines have been carried out to determine the factors which might have influenced the stability of photosensitized phthalocyanines. Complexes of the molecular type Mpc, M'(2)pc, and Lnpc(2) (where M = Li, Mg, Fe, Co, Zn, P... |
12950220 | Self-assembly of coordination polymers from AgX (X = SbF(6)(-), PF(6)(-), and CF(3)SO(3)(-)) and oxadiazole-containing ligands. | The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L1), 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2), and 2,5-bis(3-aminophenyl)-1,3,4-oxadiazole (L3) with inorganic Ag(I) salts has been investigated. Four new coordination polymers (1, 2, 3, and 5) and one n... |
12950218 | Formation of dinuclear, macrocyclic, and chain structures from HgI(2) and a semirigid benzimidazole-based bridging ligand: an example of ring-opening supramolecular isomerism. | The reactions of HgI(2) with the semirigid ditopic ligand 1,3-bis(benzimidazol-1-ylmethyl)-2,4,6-trimethylbenzene (bbimms) afforded three new complexes, [Hg(2)(mu-I)(2)I(2)(bbimms)] (1), [Hg(2)I(4)(bbimms)(2)] (2), and catena-poly[HgI(2)(bbimms)] (3). The ligand and all complexes have been structurally characterized by... |
12950214 | Crucial role of the counteranion on the templation of metallomacrocycles and a 3D network: synthesis, characterization, and structural analysis. | Two novel supramolecular architectures, [[Ag(2)L(1)(2)][X](2)] with X = CF(3)SO(3)(-) (2a) or X = NO(3)(-) (2b) and [[AgL(1)(2)][X]](n) with X = BF(4)(-) (3), were constructed by self-assembly and obtained in quantitative yields, using AgX as a building block and L(1) as the bridging ligand (L(1) = 1,3-bis(benzimidazol... |
12950207 | Binuclear copper(II) complexes of xylyl-bridged bis(1,4,7-triazacyclononane) ligands. | Copper(II) complexes of three bis(tacn) ligands, [Cu(2)(T(2)-o-X)Cl(4)] (1), [Cu(2)(T(2)-m-X)(H(2)O)(4)](ClO(4))(4).H(2)O.NaClO(4) (2), and [Cu(2)(T(2)-p-X)Cl(4)] (3), were prepared by reacting a Cu(II) salt and L.6HCl (2:1 ratio) in neutral aqueous solution [T(2)-o-X = 1,2-bis(1,4,7-triazacyclonon-1-ylmethyl)benzene; ... |
12950198 | Intermetallic interactions in face-to-face homo- and heterodinuclear bismacrocyclic complexes of copper(II) and nickel(II). | New face-to-face heterodinuclear complexes containing copper(II) and nickel(II) in identical tetraazamacrocyclic environments have been synthesized and characterized using ESI mass-spectrometry, X-ray diffraction, spectroscopic methods, and elemental analysis. These new bismacrocyclic systems were compared with the res... |
12950195 | Solvent switching of intramolecular energy transfer in bichromophoric systems: photophysics of (2,2'-bipyridine)tetracyanoruthenate(II)/pyrenyl complexes. | The supramolecular systems [Ru(Pyr(n)bpy)(CN)(4)](2-) (n = 1, 2), where one and two pyrenyl units are linked via two-methylene bridges to the [Ru(bpy)(CN)(4)](2-) chromophore, have been synthesized. The photophysical properties of these systems, which contain a highly solvatochromic metal complex moiety, have been inve... |
12950185 | Synthesis and characterization of novel grid coordination polymer networks generated from unsymmetrically bridging ligands. | Self-assembly between simple unsymmetrical ligands, such as 1-(3-pyridyl)-2-(4-pyridyl)ethene (L(1)) and 1-methyl-1'-(3-pyridyl)-2-(4-pyrimidyl)ethene (L(2)), and Co(NCS)(2) affords the unprecedented two-dimensional grid coordination polymers [Co(L(1))(2)(NCS)(2)](infinity) (1) and [Co(L(2))(2)(NCS)(2)](infinity) (2), ... |
12950171 | The prohormone processing enzyme PC3 is a lipid raft-associated transmembrane protein. | The biosynthesis of most biologically active peptides involves the action of prohomone convertases, including PC3 (also known as PC1), that catalyze limited proteolysis of precursor proteins. Proteolysis of prohormones occurs mainly in the granules of the regulated secretory pathway. It has been proposed that the targe... |
12946525 | Determination of MPTP, a toxic impurity of pethidine. | Pethidine, predominantly a mu-receptor agonist, is a phenyl-piperidinic synthetic drug. It is used in the management of moderate to several pain. A possible hydrolytic degradation of an ester group can generate a very toxic compound, the N-methyl-4-phenyl-1,2,3,6 tetrahydropyridine (MPTP) which contaminates the drug. B... |
12946151 | Homodimerization and heteroassociation of 6-O-(2-sulfonato-6-naphthyl)-gamma-cyclodextrin and 6-deoxy-(pyrene-1-carboxamido)-beta-cyclodextrin. | 6-O-(2-sulfonato-6-naphthyl)-gamma-cyclodextrin (1) and 6-deoxy-(pyrene-1-carboxamido)-beta-cyclodextrin (2) were prepared. Homodimerizations of 1 and 2 and heteroassociation between 1 and 2 were investigated by (1)H NMR, circular dichroism, and fluorescence spectroscopic methods. The compounds 1 and 2 form head-to-hea... |
12946141 | Unprecedented selective ipso-nitration of calixarenes monitored by the O-substituents. | The electrophilic ipso-reactions of a tBu-calix[6]arene that presents alternate O-methyl and O-2-methylen-N-methyl-imidazolyl groups (1) at the small rim have been studied. Whereas 1 underwent per-sulfonation in sulfuric acid, it selectively reacted with nitric acid to yield a tris-nitro derivative. The ipso-nitration ... |
12946135 | Synthesis and optical properties of unsymmetrical conjugated dendrimers focally anchored with perylenes in different geometries. | Two sets of light-harvesting monodendrons with unsymmetrical conjugated phenylacetylene branches and perylene cores, one with pi-conjugation from the branches to the core and one without, were synthesized and their photophysical properties were studied by steady-state and time-resolved spectroscopic methods. These mono... |
12946127 | Changing mechanisms in the beta-cyclodextrin-mediated hydrolysis of phenyl esters of perfluoroalkanoic acids. | The rate of hydrolysis of esters CF(3)(CF(2))(n)COOPh (1 (n = 1), 2 (n = 2), and 3 (n = 6)) was measured at pH 6.00 and at pH higher than 9.00 in the presence of beta-cyclodextrin (beta-CD). For compounds 1 and 2 the reaction rate decreases as the beta-CD concentration increases, and they show saturation effects at all... |
12946363 | Dynamics of unfolded polypeptide chains as model for the earliest steps in protein folding. | The rate of formation of intramolecular interactions in unfolded proteins determines how fast conformational space can be explored during folding. Characterization of the dynamics of unfolded proteins is therefore essential for the understanding of the earliest steps in protein folding. We used triplet-triplet energy t... |
12943426 | Formal synthesis of (-)-apicularen A. | [reaction: see text] A formal synthesis of (-)-apicularen A has been completed. The synthesis features a cyanohydrin acetonide coupling as a convergent approach to the C9-C18 segment and an intramolecular Diels-Alder addition sequence to create both the 10-membered macrocycle and the aromatic ring. |
12944485 | Megakaryoblastic leukemia 1, a potent transcriptional coactivator for serum response factor (SRF), is required for serum induction of SRF target genes. | Megakaryoblastic leukemia 1 (MKL1) is a myocardin-related transcription factor that we found strongly activated serum response element (SRE)-dependent reporter genes through its direct binding to serum response factor (SRF). The c-fos SRE is regulated by mitogen-activated protein kinase phosphorylation of ternary compl... |
12944465 | Rad52-independent accumulation of joint circular minichromosomes during S phase in Saccharomyces cerevisiae. | We investigated the formation of X-shaped molecules consisting of joint circular minichromosomes (joint molecules) in Saccharomyces cerevisiae by two-dimensional neutral/neutral gel electrophoresis of psoralen-cross-linked DNA. The appearance of joint molecules was found to be replication dependent. The joint molecules... |
15139709 | [Abdominal "packing": indications and method]. | Abdominal packing is a lifesaving technique for temporary control of severe injury and it is used in damage control surgery schedule. Technically bleeding from abdominal cavity can generally be achieved by applying pressure with several large abdominal packs. Its possible too applying packs in organ-specific techniques... |
12944316 | Reconstituted fusion pore. | Fusion pores or porosomes are basket-like structures at the cell plasma membrane, at the base of which, membrane-bound secretory vesicles dock and fuse to release vesicular contents. Earlier studies using atomic force microscopy (AFM) demonstrated the presence of fusion pores at the cell plasma membrane in a number of ... |
12944309 | Identification of binding mechanisms in single molecule-DNA complexes. | Changes in the elastic properties of single deoxyribonucleic acid (DNA) molecules in the presence of different DNA-binding agents are identified using atomic force microscope single molecule force spectroscopy. We investigated the binding of poly(dG-dC) dsDNA with the minor groove binder distamycin A, two supposed majo... |
12944304 | Dehydron: a structurally encoded signal for protein interaction. | We introduce a quantifiable structural motif, called dehydron, that is shown to be central to protein-protein interactions. A dehydron is a defectively packed backbone hydrogen bond suggesting preformed monomeric structure whose Coulomb energy is highly sensitive to binding-induced water exclusion. Such preformed hydro... |
12944293 | Formation pathways of a guanine-quadruplex DNA revealed by molecular dynamics and thermodynamic analysis of the substates. | The formation of a cation-stabilized guanine quadruplex (G-DNA) stem is an exceptionally slow process involving complex kinetics that has not yet been characterized at atomic resolution. Here, we investigate the formation of a parallel stranded G-DNA stem consisting of four strands of d(GGGG) using molecular dynamics s... |
12944280 | Sorting of lipids and transmembrane peptides between detergent-soluble bilayers and detergent-resistant rafts. | Specific proteins and lipids sequester to regions of cell membranes called rafts. Due to their high content of sphingomyelin (SM) and cholesterol, raft bilayers are thicker than nonraft bilayers and, at least at 4 degrees C, are resistant to Triton X-100 extraction. It has been postulated that rafts concentrate protein... |
12944278 | Kinetics of the micelle-to-vesicle transition: aqueous lecithin-bile salt mixtures. | Important routes to lipid vesicles (liposomes) are detergent removal techniques, such as dialysis or dilution. Although they are widely applied, there has been only limited understanding about the structural evolution during the formation of vesicles and the parameters that determine their properties. We use time-resol... |
12944277 | A new mechanism of model membrane fusion determined from Monte Carlo simulation. | We have carried out extensive Monte Carlo simulations of the fusion of tense apposed bilayers formed by amphiphilic molecules within the framework of a coarse-grained lattice model. The fusion pathway differs from the usual stalk mechanism. Stalks do form between the apposed bilayers, but rather than expand radially to... |
12944273 | Enlargement and contracture of C2-ceramide channels. | Ceramides are known to play a major regulatory role in apoptosis by inducing cytochrome c release from mitochondria. We have previously reported that ceramide, but not dihydroceramide, forms large and stable channels in phospholipid membranes and outer membranes of isolated mitochondria. C(2)-ceramide channel formation... |
12944262 | Charge distribution in 7-methylguanine regarding cation-pi interaction with protein factor eIF4E. | Electric charge distribution in mRNA 5' cap terminus has been exhaustively characterized in respect to the affinity for cap-binding proteins. Formation of the stacked configuration of positively charged 7-methylguanine in between two aromatic amino acid rings, known as sandwich cation-pi stacking, is thought to be prer... |
12940979 | Analysis of the biosynthetic gene cluster for the polyether antibiotic monensin in Streptomyces cinnamonensis and evidence for the role of monB and monC genes in oxidative cyclization. | The analysis of a candidate biosynthetic gene cluster (97 kbp) for the polyether ionophore monensin from Streptomyces cinnamonensis has revealed a modular polyketide synthase composed of eight separate multienzyme subunits housing a total of 12 extension modules, and flanked by numerous other genes for which a plausibl... |
12941925 | Hepatitis C virus-like particle budding: role of the core protein and importance of its Asp111. | In the absence of a hepatitis C virus (HCV) culture system, the use of a Semliki Forest virus replicon expressing genes encoding HCV structural proteins that assemble into HCV-like particles provides an opportunity to study HCV morphogenesis. Using this system, we showed that the HCV core protein constitutes the buddin... |
12941907 | Integrin-using rotaviruses bind alpha2beta1 integrin alpha2 I domain via VP4 DGE sequence and recognize alphaXbeta2 and alphaVbeta3 by using VP7 during cell entry. | Integrins alpha2beta1, alphaXbeta2, and alphaVbeta3 have been implicated in rotavirus cell attachment and entry. The virus spike protein VP4 contains the alpha2beta1 ligand sequence DGE at amino acid positions 308 to 310, and the outer capsid protein VP7 contains the alphaXbeta2 ligand sequence GPR. To determine the vi... |
12941902 | Human T-cell leukemia virus type 1 envelope glycoprotein gp46 interacts with cell surface heparan sulfate proteoglycans. | The major receptors required for attachment and entry of the human T-cell leukemia virus type 1 (HTLV-1) remain to be identified. Here we demonstrate that a functional, soluble form of the HTLV-1 surface envelope glycoprotein, gp46, fused to an immunoglobulin Fc region (gp46-Fc) binds to heparan sulfate proteoglycans (... |
12941090 | Analytic quantification of solar lentigines lightening by a 2% hydroquinone-cyclodextrin formulation. | <h4>Background</h4>The innate melanin pigmentation of skin is modulated during lifetime by a series of factors, including ageing and chronic ultraviolet light exposure. Actinic lentigines may be of particular concern from a cosmetic point of view. Conventional hypopigmenting agents are usually deceptive. Using cyclodex... |
12940758 | Hierarchical assembly of two-dimensional homochiral nanocavity arrays. | We demonstrate the rational design of nanoporous two-dimensional supramolecular structures by the hierarchical assembly of organic molecules and transition metal atoms at surfaces. Single-molecule level observations with scanning tunneling microscopy monitor the successive aufbau of structures with increasing complexit... |
12940746 | Convenient scaffold for forming heteroporphyrin arrays in aqueous media. | A new methodology for preparing heteroporphyrin arrays in aqueous solution has been presented. The present method is based on the extremely strong ability of heptakis(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMe-beta-CD) to include 5,10,15,20-tetrakis(p-substituted-phenyl)porphyrins (Por) affording trans-type 1:2 complex... |
12940723 | Dendrimer disassembly by benzyl ether depolymerization. | The disassembly of dendritic structures was realized by a cascade cleavage reaction triggered by an initially stimulated group in the dendrimer periphery. A depolymerizable backbone was engineered into prototypical dendritic structures. Evidence for the completion of the disassembly process is provided by the absorbanc... |
12940719 | A supramolecular approach to an allosteric catalyst. | The design and synthesis of a novel, supramolecular allosteric catalyst system, assembled via the weak-link approach, is presented. The catalyst contains two structural Rh(I) centers in thioether- and phosphine-rich hemilabile pockets, and two functional Cr(III) centers bound within salen-based moieties. The catalytic ... |
12939394 | The Ca-activated Cl channel and its control in rat olfactory receptor neurons. | Odorants activate sensory transduction in olfactory receptor neurons (ORNs) via a cAMP-signaling cascade, which results in the opening of nonselective, cyclic nucleotide-gated (CNG) channels. The consequent Ca2+ influx through CNG channels activates Cl channels, which serve to amplify the transduction signal. We invest... |
12939642 | Biased epitope selection by recombinant vaccinia-virus (rVV)-infected mature or immature dendritic cells. | Recombinant expression vectors represent a powerful way to deliver whole antigens (Ags) for immunization. Sustained Ag expression in vector-infected dendritic cells (DC) combines Ag-specific stimulation with powerful costimulation and, simultaneously, through 'self-selection' of ad hoc epitopes broadens the scope of im... |
12938224 | A physical and functional link between cholesterol and tetraspanins. | By interacting with each others, the tetraspanins are thought to assemble a network of molecular interactions, the tetraspanin web. These tetraspanin/tetraspanin interactions involve in part the palmitoylation of the proteins. We show that tetraspanins interact with cholesterol as indicated by the precipitation of tetr... |
12937145 | Vascular smooth muscle cells orchestrate the assembly of type I collagen via alpha2beta1 integrin, RhoA, and fibronectin polymerization. | Assembly of collagen into fibrils is widely studied as a spontaneous and entropy-driven process. To determine whether vascular smooth muscle cells (SMCs) impact the formation of collagen fibrils, we microscopically tracked the conversion of soluble to insoluble collagen in human SMC cultures, using fluorescent type I c... |
12933880 | Ehrlichia chaffeensis and Anaplasma phagocytophilum lack genes for lipid A biosynthesis and incorporate cholesterol for their survival. | Ehrlichia chaffeensis and Anaplasma phagocytophilum are agents of human monocytic and granulocytic ehrlichioses, respectively. They are extremely sensitive to mechanical stress and are pleomorphic gram-negative bacteria. Membrane incorporation of cholesterol from the eukaryotic host is known to be essential for other f... |
12933835 | Bordetella pertussis acquires resistance to complement-mediated killing in vivo. | In order to initially colonize a host, bacteria must avoid various components of the innate immune system, one of which is complement. The genus Bordetella includes three closely related species that differ in their ability to resist complement-mediated killing. Bordetella parapertussis and Bordetella bronchiseptica re... |
12933659 | Multiple determinants for rapid agonist-induced internalization of a nonmammalian gonadotropin-releasing hormone receptor: a putative palmitoylation site and threonine doublet within the carboxyl-terminal tail Are critical. | The chicken GnRH receptor (cGnRH-R) differs from all mammalian GnRH-Rs in possessing a cytoplasmic carboxyl-terminal tail. We have previously demonstrated that the cGnRH-R undergoes more rapid agonist-induced internalization than the mammalian GnRH-Rs and requires the carboxyl-terminal tail for this process. To investi... |
12931008 | Asymmetric mutation rates at enzyme-inhibitor interfaces: implications for the protein-protein docking problem. | We have carried out a thorough and systematic sequence-structure study on how the pattern of conservation at the interface differs from the noninteracting surface in seven proteases and their inhibitors. As expected, the interface of a protease could be easily distinguished from the noninteracting surface by a concentr... |
12931004 | Prospects and limitations of the rational engineering of fibrillar collagens. | Recombinant collagens are attractive proteins for a number of biomedical applications. To date, significant progress was made in the large-scale production of nonmodified recombinant collagens; however, engineering of novel collagen-like proteins according to customized specifications has not been addressed. Herein we ... |
12930995 | Site2 binding energetics of the regulatory step of growth hormone-induced receptor homodimerization. | Receptor signaling in the growth hormone (GH)-growth hormone receptor (GHR) system is controlled through a sequential two-step hormone-induced dimerization of two copies of the extracellular domain (ECD) of the receptor. The regulatory step of this process is the binding of the second ECD (ECD2) to the stable preassoci... |
12930991 | The binding of beta- and gamma-cyclodextrins to glycogen phosphorylase b: kinetic and crystallographic studies. | A number of regulatory binding sites of glycogen phosphorylase (GP), such as the catalytic, the inhibitor, and the new allosteric sites are currently under investigation as targets for inhibition of hepatic glycogenolysis under high glucose concentrations; in some cases specific inhibitors are under evaluation in human... |
12930989 | Calculating pKa values in enzyme active sites. | The ionization properties of the active-site residues in enzymes are of considerable interest in the study of the catalytic mechanisms of enzymes. Knowledge of these ionization constants (pKa values) often allows the researcher to identify the proton donor and the catalytic nucleophile in the reaction mechanism of the ... |
12930981 | Structural genomics: computational methods for structure analysis. | The success of structural genomics initiatives requires the development and application of tools for structure analysis, prediction, and annotation. In this paper we review recent developments in these areas; specifically structure alignment, the detection of remote homologs and analogs, homology modeling and the use o... |
12930968 | A positively charged side chain at position 154 on the beta8-alphaE loop of HIV-1 RT is required for stable ternary complex formation. | Lys154 is the only positively charged residue located in the VLPQGWK motif on the beta8-alphaE loop at the junction of the fingers and palm subdomains of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT). Some of the conserved residues in this motif are critical for RT function, while others have bee... |
12925995 | Recognition of double-stranded RNA by proteins and small molecules. | Molecular recognition of double-stranded RNA (dsRNA) is a key event for numerous biological pathways including the trafficking, editing, and maturation of cellular RNA, the interferon antiviral response, and RNA interference. Over the past several years, our laboratory has studied proteins and small molecules that bind... |
12925992 | Molecular recognition of aminoglycoside antibiotics by ribosomal RNA and resistance enzymes: an analysis of x-ray crystal structures. | The potential of RNA molecules to be used as therapeutic targets by small inhibitors is now well established. In this fascinating wide-open field, aminoglycoside antibiotics constitute the most studied family of RNA binding drugs. Within the last three years, several x-ray crystal structures were solved for aminoglycos... |
12775215 | Subsite structure of the endo-type chitin deacetylase from a deuteromycete, Colletotrichum lindemuthianum: an investigation using steady-state kinetic analysis and MS. | The endo-type chitin deacetylase (EC 3.5.1.41) from a deuteromycete, Colletotrichum lindemuthianum (ATCC 56676), catalyses the hydrolysis of the acetamido group of GlcNAc (2-acetamido-2-deoxy-D-glucose) residues in chitin or chito-oligosaccharides with a degree of polymerization (n) equal to or greater than 2. The stea... |
12767255 | Characterization of the bipartite nuclear localization signal of protein LANA2 from Kaposi's sarcoma-associated herpesvirus. | LANA2 is a nuclear latent protein detected exclusively in Kaposi's sarcoma-associated herpesvirus-infected B cells. The protein inhibits p53-dependent transactivation and apoptosis, suggesting an important role in the transforming activity of the virus. To explore the molecular mechanisms of its nuclear localization, f... |
12923255 | Zeptomole detection of a viral nucleic acid using a target-activated ribozyme. | We describe a strategy for the ultra-sensitive detection of nucleic acids using "half" ribozymes that are devoid of catalytic activity unless completed by a trans-acting target nucleic acid. The half-ribozyme concept was initially demonstrated using a construct derived from a multiple turnover Class I ligase. Iterative... |
12919723 | Biosynthesis of toxic glutathione conjugates from halogenated alkenes. | Glutathione conjugation has been identified as an important detoxication reaction. However, several glutathione-dependent bioactivation reactions have been identified. Current knowledge on the mechanisms and the possible biological importance of these reactions is discussed in this article. Several polychlorinated alke... |
12918043 | In vitro biocompatibility assessment of sulfonated polyrotaxane-immobilized polyurethane surfaces. | Sulfonated polyrotaxanes (PRx-SO(3)'s), in which sulfonated alpha-cyclodextrins (alpha-CDs) were threaded onto the poly(ethylene glycol) (PEG) segments in a PEG-b-poly(propylene glycol) (PPG)-b-PEG triblock copolymer (Pluronic) capped with benzyloxycarbonyl (Z)-L-phenylalanine (Z-L-Phe), were prepared as a novel surfac... |
12915580 | A bromodomain-containing protein from tomato specifically binds potato spindle tuber viroid RNA in vitro and in vivo. | For the identification of RNA-binding proteins that specifically interact with potato spindle tuber viroid (PSTVd), we subjected a tomato cDNA expression library prepared from viroid-infected leaves to an RNA ligand screening procedure. We repeatedly identified cDNA clones that expressed a protein of 602 amino acids. T... |
12915577 | Cell cycle regulation by Kaposi's sarcoma-associated herpesvirus K-bZIP: direct interaction with cyclin-CDK2 and induction of G1 growth arrest. | In order to cope with hostile host environments, many viruses have developed strategies to perturb the cellular machinery to suit their replication needs. Some herpesvirus genes protect cells from undergoing apoptosis to prolong the lives of infected cells, while others, such as Epstein-Barr virus Zta, slow down the G(... |
12915572 | CCAAT/enhancer-binding protein-alpha is induced during the early stages of Kaposi's sarcoma-associated herpesvirus (KSHV) lytic cycle reactivation and together with the KSHV replication and transcription activator (RTA) cooperatively stimulates the viral RTA, MTA, and PAN promoters. | During the immediate-early (IE) phase of reactivation from latency, the Kaposi's sarcoma-associated herpesvirus (KSHV) replication and transcription activator protein (RTA) (or ORF50) is thought to be the most critical trigger that upregulates expression of many downstream viral lytic cycle genes, including the delayed... |
12915568 | Specific association of glycoprotein B with lipid rafts during herpes simplex virus entry. | Herpes simplex virus (HSV) entry requires the interaction of glycoprotein D (gD) with a cellular receptor such as herpesvirus entry mediator (HVEM or HveA) or nectin-1 (HveC). However, the fusion mechanism is still not understood. Since cholesterol-enriched cell membrane lipid rafts are involved in the entry of other e... |
12915561 | Identification of novel immunodominant CD4+ Th1-type T-cell peptide epitopes from herpes simplex virus glycoprotein D that confer protective immunity. | The molecular characterization of the epitope repertoire on herpes simplex virus (HSV) antigens would greatly expand our knowledge of HSV immunity and improve immune interventions against herpesvirus infections. HSV glycoprotein D (gD) is an immunodominant viral coat protein and is considered an excellent vaccine candi... |
12909101 | Development of a new method for the determination of nitrosamines by micellar electrokinetic capillary chromatography. | A new method was developed for separation and quantification of nitrosamines by micellar electrokinetic capillary chromatography (MEKC). The effects of composition of the buffer, concentration of sodium dodecyl sulfate (SDS), gamma-cyclodextrin (CD) and pH on the separation and migration times of the nitrosamines were ... |
12910453 | A left-handed alpha-helix containing both L- and D-amino acids: the solution structure of the antimicrobial lipodepsipeptide tolaasin. | The 18-amino acid cytolytic lipodepsipeptide tolaasin, produced in culture by virulent strains of Pseudomonas tolaasii, is the causal agent of the brown blotch disease of the cultivated mushroom. Tolaasin has a sequence of D-amino acids in its N-terminal region, then alternates L- and D-amino acids, and bears a C-termi... |
12900925 | Comparative distribution of neuropeptide Y Y1 and Y5 receptors in the rat brain by using immunohistochemistry. | Neuropeptide Y (NPY) Y1 and Y5 receptor subtypes mediate many of NPY's diverse actions in the central nervous system. The present studies use polyclonal antibodies directed against the Y1 and Y5 receptors to map and compare the relative distribution of these NPY receptor subtypes within the rat brain. Antibody specific... |
12893170 | Expression, purification, and analysis of MOZ and MORF histone acetyltransferases. | Histone acetylation is one major mechanism by which chromatin structure and function are regulated. Besides histones, many nonhistone proteins are also acetylated in vivo. Aberrant acetylation has been linked to the development of various human diseases. Through acetylating histone and nonhistone proteins, histone acet... |
12889039 | Effects of beta-cyclodextrin-dextran polymer on stability properties of trypsin. | Dextran modified with the mono-6-pentylene-diamino-6-deoxy-beta-cyclodextrin derivative was evaluated as a thermoprotectant additive for trypsin. The optimum temperature for trypsin activity was increased by 7 degrees C in the presence of this polymer. The enzyme thermostability was increased from 48.5 to 64 degrees C ... |
12871114 | Hybrid canonical-correlation neural-network approach applied to nonnucleoside HIV-1 reverse transcriptase inhibitors (HEPT derivatives). | Beneficial antiviral HIV-1 chemotherapy is associated with adverse reactions. To optimize the desired actions and to lower the side effects of nonnucleoside HIV-1 reverse transcriptase (RT) inhibitors (NNRTIs), quantitative structure-activity relationships (QSARs) were studied by using a series of HEPT derivatives of N... |
14517608 | Cyclen substitution with urea-containing dendrimeric branches. Theoretical study considering the concept of collectivity. | Equilibrium structures of novel dendrimeric compounds consisting of 1,4,7,10-tetraazacyclododecane (cyclen) mono- to tetra-substituted with four different dendrimeric branches have been studied. It has been shown using molecular dynamics (MD) that, even in the presence of the macrocycle cyclen, the most stable conforma... |
12944628 | Microbeam synchrotron imaging of hairs from ancient Egyptian mummies. | Developments in microfocus synchrotron techniques have led to new results regarding the long-term alteration of archaeological samples of biological origin. Here, ancient hair samples from two Egyptian mummies have been analyzed using a conjunction of structural and elemental synchrotron methods. In this favored contex... |
12970109 | Spinal administration of lipoxygenase inhibitors suppresses behavioural and neurochemical manifestations of naloxone-precipitated opioid withdrawal. | 1. This study investigated the role of spinal lipoxygenase (LOX) products in the induction and expression of opioid physical dependence using behavioural assessment of withdrawal and immunostaining for CGRP and Fos protein expression in the spinal cord. 2. Administration of escalating doses (5-50 mg kg-1; i.p.) of morp... |
12939345 | Coordinated adenine nucleotide phosphohydrolysis and nucleoside signaling in posthypoxic endothelium: role of ectonucleotidases and adenosine A2B receptors. | Limited oxygen delivery to tissues (hypoxia) is common in a variety of disease states. A number of parallels exist between hypoxia and acute inflammation, including the observation that both influence vascular permeability. As such, we compared the functional influence of activated polymorphonuclear leukocytes (PMN) on... |
12942071 | Self-assembled nanoscale biosensors based on quantum dot FRET donors. | The potential of luminescent semiconductor quantum dots (QDs) to enable development of hybrid inorganic-bioreceptor sensing materials has remained largely unrealized. We report the design, formation and testing of QD-protein assemblies that function as chemical sensors. In these assemblies, multiple copies of Escherich... |
12944669 | Supramolecular structures of 2-chloro-5-methylphenol and 4-chloro-3-methylphenol (chlorocresol). | The crystal structures of the title compounds (both C(7)H(7)ClO) are characterized by two independent molecules in each of the asymmetric units and feature O--H...O, C--H...pi and pi-pi interactions. In addition, intermolecular C--H...Cl and intramolecular O--H...Cl interactions are present in 2-chloro-5-methylphenol. ... |
12944650 | A novel copper(II) complex with 1,10-phenanthroline and ciprofloxacin. | The X-ray structure analysis of the title compound, chloro[1-cyclopropyl-6-fluoro-1,4-dihydro-4-oxo-7-(piperazin-4-ium-1-yl)-3-quinolinecarboxylate-kappa(2)O(3),O(4)](1,10-phenanthroline-kappa(2)N,N')copper chloride dihydrate, [CuCl(C(17)H(18)FN(3)O(3))(C(12)H(8)N(2))]Cl x 2H(2)O or [CuCl(cfH)(phen)]Cl x 2H(2)O, where ... |
12937279 | Impairing actin filament or syndapin functions promotes accumulation of clathrin-coated vesicles at the apical plasma membrane of acinar epithelial cells. | In this article, we investigate the contributions of actin filaments and accessory proteins to apical clathrin-mediated endocytosis in primary rabbit lacrimal acini. Confocal fluorescence and electron microscopy revealed that cytochalasin D promoted apical accumulation of clathrin, alpha-adaptin, dynamin, and F-actin a... |
12937271 | Mechanism of constitutive export from the golgi: bulk flow via the formation, protrusion, and en bloc cleavage of large trans-golgi network tubular domains. | Transport of constitutive cargo proteins from the Golgi complex to the plasma membrane (PM) is known to be mediated by large tubular-saccular carriers moving along microtubules. However, the process by which these large structures emerge from the trans-Golgi network (TGN) remains unclear. Here, we address the question ... |
12933356 | Lipid raft compartmentalization of urokinase receptor signaling in human neutrophils. | Urokinase plasminogen activator (uPA) receptors (uPAR) can be engaged for activation signaling either by aggregation or by binding exogenous uPA. These signaling mechanisms require uPAR to associate with two distinct adhesion proteins, L-selectin and complement receptor 3 (CR3), respectively. uPAR contains a glycosylph... |
12937948 | DOTA-NOC, a high-affinity ligand of somatostatin receptor subtypes 2, 3 and 5 for labelling with various radiometals. | Earlier studies have shown that modification of the octapeptide octreotide in positions 3 and 8 may result in compounds with increased somatostatin receptor affinity that, if radiolabelled, display improved uptake in somatostatin receptor-positive tumours. The aim of a recent research study in our laboratory was to emp... |
12933355 | Rho kinase inhibition initiates apoptosis in human airway epithelial cells. | Disruption of the actin cytoskeleton elicits profound changes in cell survival and function. The actin cytoskeleton is regulated in a hierarchical manner by Rho GTPases. Rho kinase, a downstream effector of RhoA, regulates the formation of stress fibers and focal adhesions. Disruption of the actin cytoskeleton causes a... |
12930900 | Biomimetic organization: Octapeptide self-assembly into nanotubes of viral capsid-like dimension. | The controlled self-assembly of complex molecules into well defined hierarchical structures is a promising route for fabricating nanostructures. These nanoscale structures can be realized by naturally occurring proteins such as tobacco mosaic virus, capsid proteins, tubulin, actin, etc. Here, we report a simple alterna... |
12930829 | Involvement of the histone deacetylase SIRT1 in chicken ovalbumin upstream promoter transcription factor (COUP-TF)-interacting protein 2-mediated transcriptional repression. | Chicken ovalbumin upstream promoter transcription factor (COUP-TF)-interacting proteins 1 and 2 (CTIP1 and CTIP2) enhance transcriptional repression mediated by COUP-TF II and have been implicated in hematopoietic cell development and malignancies. CTIP1 and CTIP2 are also sequence-specific DNA-binding proteins that re... |
12928490 | Self-assembly of synthetic peptides control conformation and optical properties of a zwitterionic polythiophene derivative. | The optical transitions of a chiral, three-substituted polythiophene with an amino acid function can be tuned by interactions with synthetic peptides. The addition of a positively charged peptide with a random-coil formation will force the polymer to adopt a nonplanar conformation, and the intensity of the emitted ligh... |
12944664 | A mixed crystal of imperatorin and phellopterin, with C--H...O, C--H...pi and pi-pi interactions. | The crystal structure of 9-(3-methylbut-2-enyloxy)-7H-furo[3,2-g]chromen-7-one-4-methoxy-9-(3-methylbut-2-enyloxy)-7H-furo[3,2-g]chromen-7-one (0.926/0.074), 0.926C(16)H(14)O(4)*- x 0.074C(17)H(16)O(5), is characterized by two independent imperatorin molecules in the asymmetric unit, which exhibit different side-chain ... |
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