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10217171 | Achiral and chiral determination of tramadol and its metabolites in urine by capillary electrophoresis. | An achiral and chiral separation for the determination of tramadol and its main metabolite O-demethyltramadol in urine samples by CE with UV detection was developed. It was possible to separate tramadol and its phase I and phase II metabolites in one single run using a borate buffer. Furthermore, the simultaneous chira... |
10212937 | Virus reconstitution and the proof of the existence of genomic RNA. | This paper is a historical overview of the work done on the tobacco mosaic virus. The primary finding was that a virus is capable of reassembling itself from its component protein and RNA, and that only the RNA carries the genomic capability of the virus. This was followed by detailed studies of the chemical and biolog... |
10212936 | Historical overview of research on the tobacco mosaic virus genome: genome organization, infectivity and gene manipulation. | Early in the development of molecular biology, TMV RNA was widely used as a mRNA [corrected] that could be purified easily, and it contributed much to research on protein synthesis. Also, in the early stages of elucidation of the genetic code, artificially produced TMV mutants were widely used and provided the first pr... |
10212935 | The antigenicity of tobacco mosaic virus. | The antigenic properties of the tobacco mosaic virus (TMV) have been studied extensively for more than 50 years. Distinct antigenic determinants called neotopes and cryptotopes have been identified at the surface of intact virions and dissociated coat protein subunits, respectively, indicating that the quaternary struc... |
10212933 | Self-assembly of tobacco mosaic virus: the role of an intermediate aggregate in generating both specificity and speed. | The tobacco mosaic virus (TMV) particle was the first macromolecular structure to be shown to self-assemble in vitro, allowing detailed studies of the mechanism. Nucleation of TMV self-assembly is by the binding of a specific stem-loop of the single-stranded viral RNA into the central hole of a two-ring sub-assembly of... |
10212932 | The tobacco mosaic virus particle: structure and assembly. | A short account is given of the physical and chemical studies that have led to an understanding of the structure of the tobacco mosaic virus particle and how it is assembled from its constituent coat protein and RNA. The assembly is a much more complex process than might have been expected from the simplicity of the he... |
10212931 | Milestones in the research on tobacco mosaic virus. | Beijerinck's (1898) recognition that the cause of tobacco mosaic disease was a novel kind of pathogen became the breakthrough which eventually led to the establishment of virology as a science. Research on this agent, tobacco mosaic virus (TMV), has continued to be at the forefront of virology for the past century. Aft... |
10209765 | Yarrowia lipolytica cell wall architecture: interaction of Ywp1, a mycelial protein, with other wall components and the effect of its depletion. | Linkages of Ywp1 to other components of the Yarrowia lipolytica mycelial cell wall were studied by extraction with beta-mercaptoethanol and zymolyase (a beta-glucanase complex) and by the use of rabbit polyclonal antibody preparation raised against Ywp1. Ywp1 complexed with an N-glycosylated cell wall protein(s) to for... |
10205302 | A model for the spatial location of pyruvate dehydrogenase phosphatase in mammalian pyruvate dehydrogenase complex. | Recent experimental findings on the structural--functional features of pyruvate dehydrogenase phosphatase (PDP) isolated from various sources are compared. Two alternative mechanisms (a and b) of dephosphorylation of the E1 component in the pyruvate dehydrogenase complex (PDC) are discussed: a) the reaction occurs as a... |
10204951 | Stimulation of the inflammatory system by reamed and unreamed nailing of femoral fractures. An analysis of the second hit. | It has been suggested that reamed intramedullary nailing of the femur should be avoided in some patients with multiple injuries. We have studied prospectively the effect of femoral reaming on the inflammatory process as implicated in the pathogenesis of acute respiratory distress syndrome (ARDS) and multiple-organ fail... |
10202961 | Characterisation of the binding of digitoxin and acetyldigitoxin to human serum albumin by high-performance affinity chromatography. | Zonal elution and high-performance affinity chromatography were used to examine interactions of the drugs digitoxin and acetyldigitoxin with the protein human serum albumin (HSA). This was done by injecting small amounts of digitoxin and acetyldigitoxin onto an immobilized HSA column in the presence of mobile phases th... |
10198642 | Molecular recognition of fatty acids by peroxisome proliferator-activated receptors. | The peroxisome proliferator-activated receptors (PPARs) are nuclear receptors for fatty acids (FAs) that regulate glucose and lipid homeostasis. We report the crystal structure of the PPAR delta ligand-binding domain (LBD) bound to either the FA eicosapentaenoic acid (EPA) or the synthetic fibrate GW2433. The carboxyli... |
10198595 | [Separation and analysis of saccharides--on mainly oligosaccharides]. | Characteristics of three kinds of columns used for the separation and analyses of saccharides by HPLC, and of a pulsed amperometric detector (PAD) as a high sensitive detector for the microanalysis of saccharides were described. The following several examples of studies on the separation and analyses of saccharides wer... |
10194313 | Stability of the dimerization domain effects the cooperative DNA binding of short peptides. | The basic region peptide derived from the basic leucine zipper protein GCN4 bound specifically to the native GCN4 binding sequences in a dimeric form when the beta-cyclodextrin/adamantane dimerization domain was introduced at the C-terminus of the GCN4 basic region peptide. We describe here how the structure and stabil... |
10192107 | Inclusion complexation of furosemide in cyclodextrins. Part 2: Implication on bioavailability. | The effect of inclusion complexation of furosemide in cyclodextrins (CyD) on the bioavailability of the drug was studied on normal human volunteers. The excretion rate of the drug was determined by HPLC for a period of 24 h. post dosing. Several pharmacokinetic parameters were calculated and statistically analyzed. viz... |
10192106 | Solid state stability of ketoprofen in the presence of different excipients. | Physical mixtures of ketoprofen (KT) were prepared using different excipients, namely, lactose, mannitol, sorbitol, beta-cyclodextrin, polyvinylpyrolidone (PVP) K30, polyethyleneglycol (PEG) 20,000 and urea in a ratio of 2:1 (drug/excipient). The prepared samples as well as KT alone were stored at 40, 50 and 60 degrees... |
10100078 | Angiotensin II type 1 and type 2 receptors bind angiotensin II through different types of epitope recognition. | <h4>Objective</h4>This study was designed to demonstrate that the principle of molecular recognition underlying high-affinity binding of angiotensin II to the type 2 (AT2) receptor is distinct from that of the type 1 (AT1) receptor. In general, the same functional pharmacophores in hormones are used to bind and activat... |
10097153 | Identification of the block in targeted retroviral-mediated gene transfer. | A chimeric retroviral vector (33E67) containing a CD33-specific single-chain antibody was generated in an attempt to target cells displaying the CD33 surface antigen. The chimeric envelope protein was translated, processed, and incorporated into viral particles as efficiently as wild-type envelope protein. The viral pa... |
10097112 | Regulation of p53 expression by thymidylate synthase. | Previous studies showed that thymidylate synthase (TS), as an RNA binding protein, regulates its own synthesis by impairing the translation of TS mRNA. In this report, we present evidence that p53 expression is affected in a similar manner by TS. For these studies, we used a TS-depleted human colon cancer HCT-C cell th... |
10097107 | Scar, a WASp-related protein, activates nucleation of actin filaments by the Arp2/3 complex. | The Arp2/3 complex, a stable assembly of two actin-related proteins (Arp2 and Arp3) with five other subunits, caps the pointed end of actin filaments and nucleates actin polymerization with low efficiency. WASp and Scar are two similar proteins that bind the p21 subunit of the Arp2/3 complex, but their effect on the nu... |
10097106 | Raft association of SNAP receptors acting in apical trafficking in Madin-Darby canine kidney cells. | We have investigated the relationships between the apical sorting mechanism using lipid rafts and the soluble N-ethyl maleimide-sensitive factor attachment protein receptor (SNARE) machinery, which is involved in membrane docking and fusion. We first confirmed that anti-alpha-SNAP antibodies inhibit the apical pathway ... |
10097098 | In situ atomic force microscopy study of Alzheimer's beta-amyloid peptide on different substrates: new insights into mechanism of beta-sheet formation. | We have applied in situ atomic force microscopy to directly observe the aggregation of Alzheimer's beta-amyloid peptide (Abeta) in contact with two model solid surfaces: hydrophilic mica and hydrophobic graphite. The time course of aggregation was followed by continuous imaging of surfaces remaining in contact with 10-... |
10097075 | The role of threonine 37 in flavin reactivity of the old yellow enzyme. | Threonine 37 is conserved among all the members of the old yellow enzyme (OYE) family. The hydroxyl group of this residue forms a hydrogen bond with the C-4 oxygen atom of the FMN reaction center of the enzyme [Fox, K. M. & Karplus, P. A. (1994) Structure 2, 1089-1105]. The position of Thr-37 and its interaction with f... |
10096666 | ECM-stimulated actin bundle formation in embryonic corneal epithelia is tyrosine phosphorylation dependent. | Previous studies demonstrated that corneal epithelial cells isolated without basal lamina respond to extracellular matrix (ECM) in an actin dependent manner; the basal cell surface flattens and the actin cortical mat reorganizes. We hypothesize that the actin reorganization is initiated by intracellular signaling mecha... |
10090736 | Role of the extracellular loops of G protein-coupled receptors in ligand recognition: a molecular modeling study of the human P2Y1 receptor. | The P2Y1 receptor is a G protein-coupled receptor (GPCR) and is stimulated by extracellular ADP and ATP. Site-directed mutagenesis of the three extracellular loops (ELs) of the human P2Y1 receptor indicates the existence of two essential disulfide bridges (Cys124 in EL1 and Cys202 in EL2; Cys42 in the N-terminal segmen... |
10090733 | Nearest-neighbor thermodynamics and NMR of DNA sequences with internal A.A, C.C, G.G, and T.T mismatches. | Thermodynamic measurements are reported for 51 DNA duplexes with A.A, C.C, G.G, and T.T single mismatches in all possible Watson-Crick contexts. These measurements were used to test the applicability of the nearest-neighbor model and to calculate the 16 unique nearest-neighbor parameters for the 4 single like with like... |
10094312 | Packaging and replication regulation revealed by chimeric genome segments of double-stranded RNA bacteriophage phi6. | Bacteriophage phi6 has a double-stranded RNA genome composed of three linear segments, L, M, and S. The innermost particle in the virion of phi6, like in the other dsRNA viruses, is an RNA-dependent RNA polymerase complex, which carries out all the functions needed for the replication of the viral genome. Empty polymer... |
10094303 | The role of overlapping U1 and U11 5' splice site sequences in a negative regulator of splicing. | Splicing of Rous sarcoma virus RNA is regulated in part by a cis-acting intronic RNA element called the negative regulator of splicing (NRS). An NRS mutant affecting nt 916-923 disrupts U11 snRNP binding and reduces NRS activity (Gontarek et al., 1993, Genes & Dev 7:1926-1936). However, we observed that a U15' splice s... |
10089290 | Comparison of the IV pharmacokinetics in sheep of miconazole-cyclodextrin solutions and a micellar solution. | The pharmacokinetics of miconazole were studied after intravenous administration to six sheep (4 mg/kg) of three aqueous solutions: a marketed micellar solution containing polyoxyl-35 castor oil (Daktarin IV(R)) was compared with two solutions both containing 50 mM lactic acid and a cyclodextrin derivative (100 mM HP-b... |
10089459 | Determination of the structure of seleno-methionine-labelled hydroxymethylbilane synthase in its active form by multi-wavelength anomalous dispersion. | The enzyme hydroxymethylbilane synthase (HMBS, E.C. 4.3.1.8) catalyzes the conversion of porphobilinogen into hydroxymethylbilane, a key intermediate for the biosynthesis of heme, chlorophylls, vitamin B12 and related macrocycles. The enzyme is found in all organisms, except viruses. The crystal structure of the seleno... |
10091669 | Covalent modification of Lys19 in the CTP binding site of cytidine 5'-monophosphate N-acetylneuraminic acid synthetase. | Periodate oxidized CTP (oCTP) was used to investigate the importance of lysine residues in the CTP binding site of the cytidine 5'-monophosphate N-acetylneuraminic acid (CMP-NeuAc) synthetase (EC 2.7.7.43) from Haemophilus ducreyi. The reaction of oCTP with the enzyme follows pseudo-first-order saturation kinetics, giv... |
10091666 | Cloning, mutagenesis, and structural analysis of human pancreatic alpha-amylase expressed in Pichia pastoris. | Human pancreatic alpha-amylase (HPA) was expressed in the methylotrophic yeast Pichia pastoris and two mutants (D197A and D197N) of a completely conserved active site carboxylic acid were generated. All recombinant proteins were shown by electrospray ionization mass spectrometry (ESI-MS) to be glycosylated and the site... |
10091663 | Comparison of protein-protein interactions in serine protease-inhibitor and antibody-antigen complexes: implications for the protein docking problem. | The protein-protein interaction energy of 12 nonhomologous serine protease-inhibitor and 15 antibody-antigen complexes is calculated using a molecular mechanics formalism and dissected in terms of the main-chain vs. side-chain contribution, nonrotameric side-chain contributions, and amino acid residue type involvement ... |
10091661 | A survey of left-handed polyproline II helices. | Left-handed polyproline II helices (PPII) are contiguous elements of protein secondary structure in which the phi and psi angles of constituent residues are restricted to around -75 degrees and 145 degrees, respectively. They are important in structural proteins, in unfolded states and as ligands for signaling proteins... |
10091650 | Solution assembly of the pseudo-high affinity and intermediate affinity interleukin-2 receptor complexes. | The high affinity interleukin-2 receptor is composed of three cell surface subunits, IL-2Ralpha, IL-2Rbeta, and IL-2Rgamma. Functional forms of the IL-2 receptor exist, however, that enlist only two of the three subunits. On activated T-cells, the alpha- and beta-subunits combine as a preformed heterodimer (the pseudo-... |
10089820 | Photophysics of melatonin in different environments. | Melatonin (N-acetyl-5-methoxytryptamine) is a naturally occurring hormone with a structural resemblance to tryptophan. Its fluorescence is solvent dependent and strongly quenched in the presence of oxygen. Fluorescence quenching in aqueous and organic solutions have been studied in the presence of different quenchers. ... |
10087266 | Rho GTPases control polarity, protrusion, and adhesion during cell movement. | Cell movement is essential during embryogenesis to establish tissue patterns and to drive morphogenetic pathways and in the adult for tissue repair and to direct cells to sites of infection. Animal cells move by crawling and the driving force is derived primarily from the coordinated assembly and disassembly of actin f... |
10087256 | A conserved biogenesis pathway for nucleoporins: proteolytic processing of a 186-kilodalton precursor generates Nup98 and the novel nucleoporin, Nup96. | The mammalian nuclear pore complex (NPC) is comprised of approximately 50 unique proteins, collectively known as nucleoporins. Through fractionation of rat liver nuclei, we have isolated >30 potentially novel nucleoporins and have begun a systematic characterization of these proteins. Here, we present the characterizat... |
10090208 | Microscopy for recognition of individual biomolecules. | One frontier challenge in microscopy and analytical chemistry is the analysis of soft matter at the single molecule level with biological systems as most complex examples. Towards this goal we have developed two novel microscopy methods. Both employ highly specific molecular recognition schemes used by nature-the recog... |
10085287 | SNARE membrane trafficking dynamics in vivo. | The ER/Golgi soluble NSF attachment protein receptor (SNARE) membrin, rsec22b, and rbet1 are enriched in approximately 1-micrometer cytoplasmic structures that lie very close to the ER. These appear to be ER exit sites since secretory cargo concentrates in and exits from these structures. rsec22b and rbet1 fused to flu... |
10085143 | Ligand binding properties of the very low density lipoprotein receptor. Absence of the third complement-type repeat encoded by exon 4 is associated with reduced binding of Mr 40,000 receptor-associated protein. | The very low density lipoprotein receptor (VLDLR) binds, among other ligands, the Mr 40,000 receptor-associated protein (RAP) and a variety of serine proteinase-serpin complexes, including complexes of the proteinase urokinase-type plasminogen activator (uPA) with the serpins plasminogen activator inhibitor-1 (PAI-1) a... |
10082963 | Small angle X-ray scattering of wheat seed-storage proteins: alpha-, gamma- and omega-gliadins and the high molecular weight (HMW) subunits of glutenin. | Small angle X-ray scattering in solution was performed on seed-storage proteins from wheat. Three different groups of gliadins (alpha-, gamma- and omega-) and a high molecular weight (HMW) subunit of glutenin (1Bx20) were studied to determine molecular size parameters. All the gliadins could be modelled as prolate elli... |
10082948 | Q-Band resonance Raman investigation of turnip cytochrome f and Rhodobacter capsulatus cytochrome c1. | The results of a comprehensive Q-band resonance Raman investigation of cytochrome c1 and cytochrome f subunits of bc1 and b6f complexes are presented. Q-band excitation provides a particularly effective probe of the local heme environments of these species. The effects of protein conformation (particularly axial ligati... |
10080933 | Combinatorial chemistry reveals a new motif that binds the platelet fibrinogen receptor, gpIIbIIIa. | Among cell adhesion molecules, the classic Arg-Gly-Asp (RGD) motif is the best studied. We used combinatorial chemical and affinity immunochemical methods to find a novel motif of unnatural peptide ligands for the fibrinogen receptor of platelets, gpIIbIIIa (alphaIIbbeta3). The new d-amino acid motif, p(f/y)l, is uniqu... |
29711774 | Template-Directed Self-Recognition of Alkyl-Bridged Bis(catechol) Ligands in the Formation of Helicate-Type Complexes. | A controlling influence on the self-assembly in the complexation reaction of a mixture of methylene- and ethylene-bridged bis(catechol) ligands (1-H<sub>4</sub> and 2-H<sub>4</sub> , respectively) with titanium(IV) ions is exerted by alkali metal cations (see scheme). Thus, not a complicated mixture of complexes, but a... |
29711762 | A Self-Assembled Calix[4]arene Dimer Linked through Hydrogen-Bonded 2-Ureidopyrimidin-4(1H)-one Groups. | Tightly linked! A linear array of complementary hydrogen bonds forms between two 2-ureidopyrimidin-4(1H)-one rings attached to the upper rims of facing 1,3-alternate calix[4]arenes (shown schematically). The strength of the binding (K<sub>ass</sub> >10<sup>6</sup> M<sup>-1</sup> in chloroform) and the efficiency of th... |
29711760 | Easy Access to Soluble Polyanions-Stabilization of the One-Dimensional Chain <sup>1</sup><sub>∞</sub> [K<sub>4</sub> Sn<sub>9</sub> ] by [18]Crown-6 in [K<sub>4</sub> Sn<sub>9</sub> ([18]crown-6)<sub>3</sub> ]⋅ethylenediamine. | Well-characterized Group 14 Zintl anions were accessible by solution methods only in low yields up to now. An easy and inexpensive reaction route to polyanions, which starts from the elements, is admissible through the usage of [18]crown-6 as reaction medium at 40°C. The [K([18]crown-6)] unit proves to be an advantageo... |
29711758 | Helical Coordination Polymers with Large Chiral Cavities. | A quarter of the unit cell volume of [{Ni(4,4'-dipy)(3-nitrobenzoate)<sub>2</sub> (MeOH)<sub>2</sub> }<sub>n</sub> ], which crystallizes in the form of helices, is occupied by large chiral cavities (400-500 Å<sup>3</sup> ). The cavities are capable of encapsulating not only single molecules, but also face-to-face dimer... |
29711756 | Selective Vesicle Formation from Calixarenes by Self-Assembly. | Amphiphilic polyhydroxy macrocycles self-assemble in water to form vesicles selectively. These vesicles are uniform in size (50-200 nm; see representation) and stable both in aqueous solution and in dried form. The selective mode of aggregation can be correlated with structural characteristics of the phenolic amphiphil... |
29711753 | Modeling the Selectivity of Potassium Channels with Synthetic, Ligand-Assembled π Slides. | A supramolecular ion channel model mediates transmembrane ion transport (shown schematically) with a selectivity topology similar to that of K<sup>+</sup> channels. This supports the biological significance of flexible arene arrays as selective cation binding sites. |
29711654 | Homogeneous Hydrogenation Catalysis with Monodisperse, Dendrimer-Encapsulated Pd and Pt Nanoparticles. | Extraordinarily stable, monodisperse noble metal nanoparticles can be prepared by using dendrimers as both templates and stabilizers. Dendrimer-encapsulated Pd nanoparticles (see the schematic representation) exhibit high catalytic activity for the hydrogenation of alkenes in water. The catalytic activity and selectivi... |
29711653 | Predetermined Chirality at Metal Centers. | Asymmetric synthesis in coordination chemistry was described very clearly by Smirnoff in 1920, but, contrary to the development in organic chemistry, it was almost completely neglected for several decades. The interest in chirality in coordination chemistry (see the stereoview of [Ru(bpy)<sub>3</sub> ]<sup>2+</sup> ) h... |
29711650 | Amphiphilic p-tert-Butylcalix[4]arene Scaffolds Containing Exposed Carbohydrate Dendrons. | The best of both worlds. Amphiphilic hybrid molecules, in which water-exposed glycodendrons are attached to a hydrophobic p-tert-butylcalix[4]arene scaffold, display strong affinities for both carbohydrate-binding proteins and polystyrene surfaces (shown schematically). The molecules can form monolayers useful in bioan... |
29711647 | High-Yielding Rotaxane Synthesis with an Anion Template. | An electrophile caught like a mouse in a trap! An anionic stopper-wheel complex acts as a supramolecular nucleophile in an almost quantitative synthesis of a phenyl ether rotaxane. The electrophilic semiaxle has to thread through the macrocycle in order to contact the bulky phenolate group that is positioned on the oth... |
29711642 | Supramolecular Catalysis of Ester and Amide Cleavage by a Dinuclear Barium(II) Complex. | Five components spontaneously self-assemble to yield the productive complex 1, where one barium ion delivers an ethoxide to the carbonyl group of an amide substrate anchored by means of a distal carboxylate moiety to the other barium ion. High substrate specificity, fairly high reaction rates with catalytic turnover, a... |
24481912 | Signal perception in plant pathogen defense. | Highly sensitive and specific recognition systems for microbial pathogens are essential for disease resistance in plants. Structurally diverse elicitors from various pathogens have been identified and shown to trigger plant defense mechanisms. Elicitor recognition by the plant is assumed to be mediated by receptors. Pl... |
21662722 | Extraction Selectivities of Crown Ethers for Alkali Metal Cations: Differences between Single-Species and Competitive Solvent Extractions. | Separation factor values for pairs of alkali metal cations determined in competitive solvent extractions of alkali metal picrates from aqueous solutions into chloroform by a variety of benzo- and cyclohexano-group-containing crown ethers vary significantly from extrapolations based upon the results of single-species ex... |
9933157 | Asymmetric scattering of polarized electrons by organized organic films of chiral molecules | Electron transmission experiments demonstrate a large asymmetry in the scattering probability of polarized electrons by thin organized films of chiral molecules. This large asymmetry results from the interaction of the electron's wavefunction with many scatterers (molecules) in the organized monolayer structure and rep... |
10024236 | Supertetrahedral sulfide crystals with giant cavities and channels | Although aluminosilicates and metal phosphates can form porous open-framework materials such as zeolites, sulfide analogs usually form high-density phases because of the relatively small tetrahedral angle at sulfur atoms. One strategy to overcome this limitation is to use tetrahedral clusters as the building blocks to ... |
11674163 | A Unified Strategy toward the Synthesis of Acerogenin-Type Macrocycles: Total Syntheses of Acerogenins A, B, C, and L and Aceroside IV. | A general strategy for the synthesis of acerogenin-type diarylheptanoids containing an endocyclic biaryl ether bond has been developed, and convergent total syntheses of acerogenin A, B, C, and L and aceroside IV have been accomplished. Cycloetherification of the linear diarylheptanoid 1-(4-fluoro-3-nitrophenyl)-7-(3-h... |
11674138 | Chiral Synthesis via Organoboranes. 46. An Efficient Preparation of Chiral Pyridino- and Thiopheno-18-crown-6 Ligands from Enantiomerically Pure C(2)-Symmetric Pyridine- and Thiophenediols(1). | Asymmetric reduction of 2,6-diacylpyridines with B-chlorodiisopinocampheylborane provides the corresponding C(2)-symmetric diols in very high de and ee. Asymmetric allylboration of 2,6-pyridinedicarboxaldehyde and 2,5-thiophenedicarboxaldehyde provides the corresponding bis-homoallylic alcohols in very high de and ee. ... |
11673944 | [(Ethylenediamine)Pt(uracilate)](4), a Metal Analogue of Calix[4]arene. Coordination and Anion Host-Guest Chemistry Related to Its Conformational Dynamics. | The open "molecular box" [(en)Pt(UH-N(1),N(3))](4)(NO(3))(4) (with en = 1,2-diaminoethane, UH = uracil monoanion) resembles calix[4]arenes in its structure and solution dynamics. It adopts a 1,3-alternate conformation in the solid-state (1a), but in solution and after deprotonation to [(en)Pt(U-N(1),N(3))](4), a second... |
10078988 | Chronic administration of adenosine A3 receptor agonist and cerebral ischemia: neuronal and glial effects. | We have previously shown that chronic administration of the selective A3 receptor agonist N6-(3-iodobenzyl)-5'-N-methylcarboxoamidoadenosine (IB-MECA) leads to a significant improvement of postocclusive cerebral blood flow, and protects against neuronal damage and mortality induced by severe forebrain ischemia in gerbi... |
10077036 | Synthesis and relaxometry of high-generation (G = 5, 7, 9, and 10) PAMAM dendrimer-DOTA-gadolinium chelates. | A series of high-generation (G) ethylenediamine-core polyamidoamine (PAMAM) dendrimers corresponding to G = 5, 7, 9, and 10 were conjugated with the bifunctional chelate 2-(4-isothiocyanatobenzyl)- 1,4,7,10-tetraazacyclododecane-N,N',N",N"'-tetraacetate (p-SCN-Bz-DOTA). Gadolinium (III) ion was added to the macromolecu... |
9889083 | Oligonucleotide and plasmid DNA packaging into polyoma VP1 virus-like particles expressed in Escherichia coli. | The drug delivery system described here is based on the properties of the capsoid or capsid-like structure resulting from the assembly of polyoma virus capsid protein VP1 expressed in Escherichia coli. The capsid protein VP1 was expressed as a fusion protein with a completely removable N-terminal His6 affinity tag. The... |
10072321 | Pyruvate decarboxylase filaments are associated with the cortical cytoskeleton of asci and spores over the sexual cycle of filamentous ascomycetes. | We show that pyruvate decarboxylase (PDC) 8- to 10-nm-diameter filaments, first described in vegetative cells of Neurospora crassa, are ubiquitously present in filamentous fungi. The cellular arrangement of these structures was examined over the entire sexual cycle of the ascomycetes N. crassa, N. tetraesperma, Podospo... |
10070875 | High efficiency of benzoporphyrin derivative in the photodynamic therapy of pigmented malignant melanoma. | Benzoporphyrin derivative monoacid ring A (verteporfin, BPD-MA) when intravenously injected (5.5 micromol kg(-1)) to C57/BL6 mice bearing a subcutaneously transplanted B1 melanoma gave a maximal accumulation in the tumour within 1-3 h with recoveries of 1.84-1.96 micromol kg(-1). Irradiation of BPD-MA-loaded melanoma w... |
10069431 | A single step purification process for cyclodextrin glucanotransferase from a Bacillus sp. isolated from soil. | Cyclodextrin glucanotransferase (CGTase) is a commercially important enzyme which catalyses the formation of cyclodextrins (CDs) from starch. A CGTase producing bacterium was isolated from soil which gave a fairly high enzyme activity of 7.5 U mL(-1) after 24 h of growth which was further increased to 22 U mL(-1) by pr... |
10052977 | Synthesis, CoMFA analysis, and receptor docking of 3,5-diacyl-2, 4-dialkylpyridine derivatives as selective A3 adenosine receptor antagonists. | 3,5-Diacyl-2,4-dialkyl-6-phenylpyridine derivatives have been found to be selective antagonists at both human and rat A3 adenosine receptors (Li et al. J. Med. Chem. 1998, 41, 3186-3201). In the present study, ring-constrained, fluoro, hydroxy, and other derivatives in this series have been synthesized and tested for a... |
10047523 | Muscle assembly: a titanic achievement? | The formation of perfectly aligned myofibrils in striated muscle represents a dramatic example of supramolecular assembly in eukaryotic cells. Recently, considerable progress has been made in deciphering the roles that titin, the third most abundant protein in muscle, has in this process. An increasing number of sarcom... |
10037798 | Matrix valency regulates integrin-mediated lymphoid adhesion via Syk kinase. | Lymphocytes accumulate within the extracellular matrix (ECM) of tumor, wound, or inflammatory tissues. These tissues are largely comprised of polymerized adhesion proteins such as fibrin and fibronectin or their fragments. Nonactivated lymphoid cells attach preferentially to polymerized ECM proteins yet are unable to a... |
10048331 | Folding of apocytochrome c induced by the interaction with negatively charged lipid micelles proceeds via a collapsed intermediate state. | Unfolded apocytochrome c acquires an alpha-helical conformation upon interaction with lipid. Folding kinetic results below and above the lipid's CMC, together with energy transfer measurements of lipid bound states, and salt-induced compact states in solution, show that the folding transition of apocytochrome c from th... |
10048326 | Sequence specificity, statistical potentials, and three-dimensional structure prediction with self-correcting distance geometry calculations of beta-sheet formation in proteins. | A statistical analysis of a representative data set of 169 known protein structures was used to analyze the specificity of residue interactions between spatial neighboring strands in beta-sheets. Pairwise potentials were derived from the frequency of residue pairs in nearest contact, second nearest and third nearest co... |
10029515 | Multiple types of association of photosystem II and its light-harvesting antenna in partially solubilized photosystem II membranes. | Photosystem II is a multisubunit pigment-protein complex embedded in the thylakoid membranes of chloroplasts. It utilizes light for photochemical energy conversion, and is heavily involved in the regulation of the energy flow. We investigated the structural organization of photosystem II and its associated light-harves... |
10024461 | Experimentally based orientational refinement of membrane protein models: A structure for the Influenza A M2 H+ channel. | The 97-residue M2 protein from Influenza A virus forms H+-selective ion channels which can be attributed solely to the homo-tetrameric alpha-helical transmembrane domain. Site-directed infrared dichroism spectra were obtained for the transmembrane domain of M2, reconstituted in lipid vesicles. Data analysis yielded the... |
10021418 | Mechanism and specificity of the terminal thioesterase domain from the erythromycin polyketide synthase. | <h4>Background</h4>Polyketides are important compounds with antibiotic and anticancer activities. Several modular polyketide synthases (PKSs) contain a terminal thioesterase (TE) domain probably responsible for the release and concomitant cyclization of the fully processed polyketide chain. Because the TE domain influe... |
10022844 | Tight binding of the 5' exon to domain I of a group II self-splicing intron requires completion of the intron active site. | Group II self-splicing requires the 5' exon to form base pairs with two stretches of intronic sequence (EBS1 and EBS2) which also bind the DNA target during retrotransposition of the intron. We have used dimethyl sulfate modification of bases to obtain footprints of the 5' exon on intron Pl.LSU/2 from the mitochondrion... |
10022842 | In vivo expression of the nucleolar group I intron-encoded I-dirI homing endonuclease involves the removal of a spliceosomal intron. | The Didymium iridis DiSSU1 intron is located in the nuclear SSU rDNA and has an unusual twin-ribozyme organization. One of the ribozymes (DiGIR2) catalyses intron excision and exon ligation. The other ribozyme (DiGIR1), which along with the endonuclease-encoding I-DirI open reading frame (ORF) is inserted in DiGIR2, ca... |
10022829 | Binding of the G domains of laminin alpha1 and alpha2 chains and perlecan to heparin, sulfatides, alpha-dystroglycan and several extracellular matrix proteins. | The C-terminal G domain of the mouse laminin alpha2 chain consists of five lamin-type G domain (LG) modules (alpha2LG1 to alpha2LG5) and was obtained as several recombinant fragments, corresponding to either individual modules or the tandem arrays alpha2LG1-3 and alpha2LG4-5. These fragments were compared with similar ... |
10022822 | Crystal structure of MHC class II-associated p41 Ii fragment bound to cathepsin L reveals the structural basis for differentiation between cathepsins L and S. | The lysosomal cysteine proteases cathepsins S and L play crucial roles in the degradation of the invariant chain during maturation of MHC class II molecules and antigen processing. The p41 form of the invariant chain includes a fragment which specifically inhibits cathepsin L but not S. The crystal structure of the p41... |
9990029 | Structural analysis at 2.2 A of orthorhombic crystals presents the asymmetry of the allophycocyanin-linker complex, AP.LC7.8, from phycobilisomes of Mastigocladus laminosus. | An electrophoretically purified allophycocyanin-linker complex, AP. LC7.8, from phycobilisomes of Mastigocladus laminosus has been crystallized in the orthorhombic space group P212121. Cryocrystallographic x-ray measurements enabled the structural analysis of the complex at a resolution of 2.2 A. The asymmetric unit co... |
9990027 | Forced unfolding of the fibronectin type III module reveals a tensile molecular recognition switch. | The 10th type III module of fibronectin possesses a beta-sandwich structure consisting of seven beta-strands (A-G) that are arranged in two antiparallel sheets. It mediates cell adhesion to surfaces via its integrin binding motif, Arg78, Gly79, and Asp80 (RGD), which is placed at the apex of the loop connecting beta-st... |
9990018 | The charged region of Hsp90 modulates the function of the N-terminal domain. | Hsp90, an abundant heat shock protein that is highly expressed even under physiological conditions, is involved in the folding of key molecules of the cellular signal transduction system such as kinases and steroid receptors. It seems to contain two chaperone sites differing in substrate specificity. Binding of ATP or ... |
9990008 | Principles of quasi-equivalence and Euclidean geometry govern the assembly of cubic and dodecahedral cores of pyruvate dehydrogenase complexes. | The pyruvate dehydrogenase multienzyme complex (Mr of 5-10 million) is assembled around a structural core formed of multiple copies of dihydrolipoyl acetyltransferase (E2p), which exhibits the shape of either a cube or a dodecahedron, depending on the source. The crystal structures of the 60-meric dihydrolipoyl acyltra... |
9990004 | Structure-activity analysis of synthetic autoinducing thiolactone peptides from Staphylococcus aureus responsible for virulence. | The synthesis of virulence factors and other extracellular proteins responsible for pathogenicity in Staphylococcus aureus is under the control of the agr locus. A secreted agr-encoded peptide, AgrD, processed from the AgrD gene product, is known to be an effector of self-strain activation and cross-strain inhibition o... |
9925526 | Comparison of a new triazole antifungal agent, Schering 56592, with itraconazole and amphotericin B for treatment of histoplasmosis in immunocompetent mice. | A murine model of intratracheally induced histoplasmosis was used to evaluate a new triazole antifungal agent, Schering (SCH) 56592, for treatment of histoplasmosis. MICs were determined for SCH 56592, amphotericin B, and itraconazole by testing yeast-phase isolates from 20 patients by a macrobroth dilution method. The... |
9925523 | ParC and GyrA may be interchangeable initial targets of some fluoroquinolones in Streptococcus pneumoniae. | To evaluate the role of known topoisomerase IV and gyrase mutations in the fluoroquinolone (FQ) resistance of Streptococcus pneumoniae, we transformed susceptible strain R6 with PCR-generated fragments encompassing the quinolone resistance-determining regions (QRDRs) of parC or gyrA from different recently characterize... |
9988760 | Non-lamellar structure and negative charges of lipopolysaccharides required for efficient folding of outer membrane protein PhoE of Escherichia coli. | Lipopolysaccharides (LPS) are amphiphilic molecules in the outer leaflet of the bacterial outer membrane. Recently, an early role for LPS in the folding of outer membrane porin PhoE was demonstrated in vitro. In order to elucidate the molecular mechanism of LPS-protein interactions, folding of PhoE protein was studied ... |
9974389 | A giant protease with potential to substitute for some functions of the proteasome. | An alanyl-alanyl-phenylalanyl-7-amino-4-methylcoumarin-hydrolyzing protease particle copurifying with 26S proteasomes was isolated and identified as tripeptidyl peptidase II (TPPII), a cytosolic subtilisin-like peptidase of unknown function. The particle is larger than the 26S proteasome and has a rod-shaped, dynamic s... |
9971905 | The effect of methylated beta-cyclodextrins on the tight junctions of the rat nasal respiratory epithelium: electron microscopic and confocal laser scanning microscopic visualization studies. | The nasal absorption enhancer randomly methylated beta-cyclodextrin (RAMEB) is thought to increase the paracellular permeability of the nasal epithelium by opening of the tight junctions. The effects of RAMEB on the cytoskeleton of the rat nasal epithelium in vivo were determined by confocal laser scanning microscopy (... |
9950683 | A cell-free system to study regulation of focal adhesions and of the connected actin cytoskeleton. | Assembly and modulation of focal adhesions during dynamic adhesive processes are poorly understood. We describe here the use of ventral plasma membranes from adherent fibroblasts to explore mechanisms regulating integrin distribution and function in a system that preserves the integration of these receptors into the pl... |
9916034 | Oriented, active Escherichia coli RNA polymerase: an atomic force microscope study. | Combining a system for binding proteins to surfaces (Sigal, G. B., C. Bamdad, A. Barberis, J. Strominger, and G. M. Whitesides. 1996. Anal. Chem. 68:490-497) with a method for making ultraflat gold surfaces (Hegner, M., P. Wagner, and G. Semenza. 1993. Surface Sci. 291:39-46 1993) has enabled single, oriented, active E... |
9929494 | Effect of protein aggregation in the aqueous phase on the binding of membrane proteins to membranes. | Analysis of the binding of hydrophobic peptides or proteins to membranes generally assumes that the solute is monomeric in both the aqueous phase and the membrane. Simulations were performed to examine the effect of solute self-association in the aqueous phase on the binding of monomeric solute to lipid vesicles. Aggre... |
9929492 | Interaction of cholesterol with sphingomyelins and acyl-chain-matched phosphatidylcholines: a comparative study of the effect of the chain length. | In this study we have synthesized sphingomyelins (SM) and phosphatidylcholines (PC) with amide-linked or sn-2 linked acyl chains with lengths from 14 to 24 carbons. The purpose was to examine how the chain length and degree of unsaturation affected the interaction of cholesterol with these phospholipids in model membra... |
9929479 | Molecular theory of lipid-protein interaction and the Lalpha-HII transition. | We present a molecular-level theory for lipid-protein interaction and apply it to the study of lipid-mediated interactions between proteins and the protein-induced transition from the planar bilayer (Lalpha) to the inverse-hexagonal (HII) phase. The proteins are treated as rigid, membrane-spanning, hydrophobic inclusio... |
9929476 | A physical approach to reduce nonspecific adhesion in molecular recognition atomic force microscopy. | Atomic force microscopy is one of the few techniques that allow analysis of biological recognition processes at the single-molecule level. A major limitation of this approach is the nonspecific interaction between the force sensor and substrate. We have modeled the nonspecific interaction by looking at the interaction ... |
9931030 | Comparison of the sequence-selective DNA binding by peptide dimers with covalent and noncovalent dimerization domains. | Sequence-specific DNA binding proteins generally consist of more than two DNA-contacting regions to ensure the selectivity of recognition. The multiple DNA binding modules are connected either through the covalent linker or through the noncovalent dimerization domain. We have compared the DNA binding of peptide dimers ... |
9927693 | Enhancing versus suppressive effects of stress hormones on skin immune function. | Delayed-type hypersensitivity (DTH) reactions are antigen-specific cell-mediated immune responses that, depending on the antigen, mediate beneficial (e.g., resistance to viruses, bacteria, and fungi) or harmful (e.g., allergic dermatitis and autoimmunity) aspects of immune function. Contrary to the idea that stress sup... |
9927691 | The stretch-activation response may be critical to the proper functioning of the mammalian heart. | The "stretch-activation" response is essential to the generation of the oscillatory power required for the beating of insect wings. It has been conjectured but not previously shown that a stretch-activation response contributes to the performance of a beating heart. Here, we generated transgenic mice that express a hum... |
9927754 | Mutational analysis of the engrailed homeodomain recognition helix by phage display. | The homeodomain (HD) is a ubiquitous protein fold that confers DNA binding function on a superfamily of eukaryotic gene regulatory proteins. Here, the DNA binding of recognition helix variants of the HD from the engrailed gene of Drosophila melanogaster was investigated by phage display. Nineteen different combinations... |
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