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12683805 | Solubilization of single-wall carbon nanotubes by supramolecular encapsulation of helical amylose. | We have developed a simple, efficient process for solubilization of single-wall carbon nanotubes (SWNTs) with amylose in aqueous DMSO. This process requires two important conditions, presonication of SWNTs and subsequent amylose treatment in an optimum mixture of DMSO/H2O. The former step separates SWNT bundles, and th... |
12683804 | Dendrimers as ligands. Formation of a 2:1 luminescent complex between a dendrimer with a 1,4,8,11-tetraazacyclotetradecane (cyclam) core and Zn2+. | We have investigated the formation of metal complexes between Zn2+ and two derivatives, 1 and 2, of the well-known 1,4,8,11-tetraazacyclotetradecane (cyclam) ligand. Compound 1 is 1,4,8,11-tetrakis(naphthylmethyl) cyclam, and compound 2 is a dendrimer consisting of a cyclam core with appended 12 dimethoxybenzene and 16... |
12684370 | Nuclear import of zinc binuclear cluster proteins proceeds through multiple, overlapping transport pathways. | In Aspergillus nidulans, the high transcriptional level of the ethanol utilization pathway genes (alc) is regulated by the specific activator AlcR. Here we have analyzed the mechanism of the nuclear import of AlcR, as well as that of other proteins belonging to the Zn(2)Cys(6) binuclear cluster family. The nuclear loca... |
12681511 | Engagement of CD99 triggers the exocytic transport of ganglioside GM1 and the reorganization of actin cytoskeleton. | We studied the role of lipid rafts and actin cytoskeleton in CD99-mediated signaling to elucidate the mechanism of protein transport upon CD99 engagement. CD99 engagement in Jurkat cells elicited the exocytic transport of GM1 as well as several surface molecules closely related with CD99 functions. In addition, CD99 mo... |
12681281 | Supramolecular organization in streptococcal pericellular capsules is based on hyaluronan tertiary structures. | Supramolecular organization involving a polyanionic glycan in a bacterial capsule (hyaluronan, HA, in streptococcal capsules) is revealed, for the first time, by electron-histochemical methodology previously used to elucidate ultrastructure in extracellular matrix. Capsular HA filaments thereby revealed closely resembl... |
12682015 | Structural basis for antibiotic recognition by the TipA class of multidrug-resistance transcriptional regulators. | The TipAL protein, a bacterial transcriptional regulator of the MerR family, is activated by numerous cyclic thiopeptide antibiotics. Its C-terminal drug-binding domain, TipAS, defines a subfamily of broadly distributed bacterial proteins including Mta, a central regulator of multidrug resistance in Bacillus subtilis. ... |
12682010 | Modeling the early stages of vascular network assembly. | In vertebrates, networks of capillary vessels supply tissues with nutrients. Capillary patterns are closely mimicked by endothelial cells cultured on basement membrane proteins that allow single randomly dispersed cells to self-organize into vascular networks. Here we provide a model including chemoattraction as the fu... |
12682471 | Possible role of increased oxidant stress in multiple organ failure after systemic inflammatory response syndrome. | <h4>Objective</h4>Host response to infection and other forms of tissue injury have been termed systemic inflammatory response syndrome (SIRS). This inflammatory response can frequently be accompanied by oxidative injury in one or more organ systems in the body. The objective of this report was to clarify the possible r... |
12681923 | Enhanced chemiluminescence of 6-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-3(7H)-one by attachment of a cyclomaltooligosaccharide (cyclodextrin). Attachment of cyclomaltononaose (delta-cyclodextrin). | 2-Methyl-6-(4-methoxyphenyl)imidazo[1,2-a]pyrazin-3(7H)-one (MCLA) is an oxygen-induced chemiluminescent compound. It has been shown that the chemiluminescence can be enhanced by forming a cyclomaltooligosaccharide (cyclodextrin)-bound MCLA, and therefore, in continuation of the survey of the types of cyclodextrins, in... |
12681922 | X-ray structure of the cyclomaltohexaicosaose triiodide inclusion complex provides a model for amylose-iodine at atomic resolution. | Cyclomaltohexaicosaose (CA26) is folded into two 1(2)/(3) turns long V-helices that are oriented antiparallel. Crystals of complexes of CA26 with NH(4)I(3) and Ba(I(3))(2) are brown and X-ray analyses show that I(3)(-) units are located in the approximately 5 A wide central channels of the V-helices. In the complex wit... |
12680759 | Relation between interface properties and kinetics of electron transfer in the interaction of cytochrome f and plastocyanin from plants and the cyanobacterium Phormidium laminosum. | Cytochrome f and plastocyanin from the cyanobacterium Phormidium laminosum react an order of magnitude faster than their counterparts from chloroplasts when long-range electrostatic interactions have been screened out by high salt concentration [Schlarb-Ridley, B. G., et al. (2002) Biochemistry 41, 3279-3285]. To inves... |
12679945 | The influence of Enteral Nutrition in postoperative patients with poor liver function. | <h4>Aim</h4>To investigate the safety, rationality and the practicality of enteral nutritional (EN) support in the postoperative patients with damaged liver function and the protective effect of EN on the gut barrier.<h4>Methods</h4>135 patients with liver function of Child B or C grade were randomly allocated to enter... |
12676613 | Interaction of organophosphate pesticides and related compounds with the androgen receptor. | Identification of several environmental chemicals capable of binding to the androgen receptor (AR) and interfering with its normal function has heightened concern about adverse effects across a broad spectrum of environmental chemicals. We previously demonstrated AR antagonist activity of the organophosphate (OP) pesti... |
12676605 | Effects of a diphenyl ether-type herbicide, chlornitrofen, and its amino derivative on androgen and estrogen receptor activities. | Chlornitrofen (CNP) was widely used in large quantities as a herbicide in rice paddy fields in Japan during 1965-1994. Recently, there has been concern that chemicals in the environment may disrupt the endocrine function of wildlife and humans, but little is known about the effect of CNP on endocrine function. We have ... |
12517304 | A proteomic approach to the identification of heterogeneous nuclear ribonucleoproteins as a new family of poly(ADP-ribose)-binding proteins. | A new class of poly(ADP-ribose) (pADPr)-binding proteins, heterogeneous nuclear ribonucleoproteins (hnRNPs), has been identified by a proteomic approach using matrix-assisted laser-desorption-ionization time-of-flight ('MALDI-TOF') MS. Liquid-phase isoelectric focusing with a Rotofor cell (Bio-Rad) allowed pre-fraction... |
12676705 | Surface display of the receptor-binding region of the Lactobacillus brevis S-layer protein in Lactococcus lactis provides nonadhesive lactococci with the ability to adhere to intestinal epithelial cells. | Lactobacillus brevis is a promising lactic acid bacterium for use as a probiotic dietary adjunct and a vaccine vector. The N-terminal region of the S-layer protein (SlpA) of L. brevis ATCC 8287 was recently shown to mediate adhesion to various human cell lines in vitro. In this study, a surface display cassette was con... |
12676675 | Expression of heteropolymeric ferritin improves iron storage in Saccharomyces cerevisiae. | Saccharomyces cerevisiae was engineered to express different amount of heavy (H)- and light (L)-chain subunits of human ferritin by using a low-copy integrative vector (YIp) and a high-copy episomal vector (YEp). In addition to pep4::HIS3 allele, the expression host strain was bred to have the selection markers leu2(-)... |
12672608 | Phosphatidylethanolamine mediated destabilization of lipid-based pDNA delivery systems. | We have previously reported the development of lipid-DNA particles (LDPs) formed, via a hydrophobic cationic lipid-DNA complex intermediate, when detergent-solubilized cationic lipids are mixed with DNA. This study investigates the influence of zwitterionic co-lipid headgroups on the formation and stability of this int... |
12672996 | Capillary electrophoresis for simultaneous determination of emodin, chrysophanol, and their 8-beta-D-glucosides. | The simultaneous separation and determination of the major anthraquinones, emodin, chrysophanol, and their glucosides, of Rumex japonicus HOUTT., and emodin and emodin glucoside, of Cassia tora L., Rhamnus purshiana DC., Polygonum multiflorum THUNB., and P. cuspidatum SIEB. et ZUCC., were achieved by cyclodextrin modif... |
12670985 | Peptide-peptide interactions between human transferrin and transferrin-binding protein B from Moraxella catarrhalis. | Transferrin-binding protein B (TbpB) is one component of a bipartite receptor in several gram-negative bacterial species that binds host transferrin and mediates the uptake of iron for growth. Transferrin and TbpB are both bilobed proteins, and the interaction between these proteins seems to involve similar lobe-lobe i... |
12670977 | Porphyrin-mediated cell surface heme capture from hemoglobin by Porphyromonas gingivalis. | The porphyrin requirements for growth recovery of Porphyromonas gingivalis in heme-depleted cultures are investigated. In addition to physiologically relevant sources of heme, growth recovery is stimulated by a number of noniron porphyrins. These data demonstrate that, as for Haemophilus influenzae, reliance on capture... |
12670962 | Subunit oligomerization and substrate recognition of the Escherichia coli ClpYQ (HslUV) protease implicated by in vivo protein-protein interactions in the yeast two-hybrid system. | The Escherichia coli ClpYQ (HslUV) is an ATP-dependent protease that consists of an ATPase large subunit with homology to other Clp family ATPases and a peptidase small subunit related to the proteasomal beta-subunits of eukaryotes. Six identical subunits of both ClpY and ClpQ self-assemble into an oligomeric ring, and... |
12670250 | Sulfonic Acid-functionalized gold nanoparticles: a colloid-bound catalyst for soft lithographic application on self-assembled monolayers. | In this report, we present a new lithographic approach to prepare patterned surfaces. Self-assembled monolayers (SAMs) of the acid-labile trimethylsilyl ether (TMS-OC(11)H(22)S)(2) (TMS adsorbate) was formed on gold. 5-Mercapto-2-benzimidazole sulfonic acid sodium salt (MBS-Na(+)) was used as a ligand for gold nanopart... |
12670245 | 2-Aminopyrimidine directed self-assembly of zinc porphyrins containing bulky 3,5-di-tert-butylphenyl groups. | The 2-aminopyrimidin-5-yl ligand is revealed to be a promising candidate for the construction of supramolecular porphyrin arrays with broad absorption bands for efficient light-harvesting. 10-Mono- and 10,20-di(2-aminopyrimidin-5-yl) derivatives of 5,15-bis(3,5-di-tert-butylphenyl)porphyrin have been synthesized in hig... |
12670236 | Anomeric configuration, glycosidic linkage, and the solution conformational entropy of O-linked disaccharides. | Oligosaccharides perform a large number of biological roles, as dictated by their chemical structure and spatial arrangement. While conformational entropies are usually determined in vacuo by computer modeling, molecular recognition processes normally take place in solution. Here I show results of experiments using siz... |
12670232 | Formation of a PNA2-DNA2 hybrid quadruplex. | DNA guanine (G) quadruplexes are stabilized by an interesting variation of the hydrogen-bonding schemes encountered in nucleic acid duplexes and triplexes. In an attempt to use this mode of molecular recognition, we target a dimeric G-quadruplex formed by the Oxytricha nova telomeric sequence d(G(4)T(4)G(4)) with a pep... |
12670226 | Diarylurea-linked zinc porphyrin dimer as a dual-mode artificial receptor: supramolecular control of complexation-facilitated photoinduced electron transfer. | A novel porphyrinic receptor 1 in which two zinc porphyrins are bridged by two diarylurea linkers was developed for recognition of a viologen derivative (hexyl viologen, HV). The electronic absorption spectra as well as the 1H NMR experiments revealed that the HV molecule was bound to the cleft in 1 mainly through carb... |
12670205 | C3v symmetric receptors show high selectivity and high affinity for phosphate. | The binding of phosphate to tripodal metalloreceptors 1 and 2 is reported. Receptors 1 and 2 are C3v symmetric, designed to complement three sides of a tetrahedron. The receptors derive from tripodal ligands that are preorganized through binding to a central Cu(II) atom. These metalloreceptors demonstrate high selectiv... |
12670395 | Protein kinase C-theta (PKCtheta): it's all about location, location, location. | Much progress has been made in understanding the function of protein kinase C-theta (PKCtheta) in the immune system since this Ca2+-independent PKC isotype was isolated in 1993 as an enzyme that is highly expressed in T lymphocytes and in muscle cells. Biochemical and genetic approaches revealed that, while dispensable... |
12671686 | Self-assembly of minimal COPII cages. | The small G-protein Sar1 and the cytosolic complexes Sec23/24 and Sec13/31 associate sequentially on endoplasmic reticulum membranes to form a protein coat named COPII, which drives the formation of transport vesicles. Using dynamic light scattering, we show that Sec23/24 and Sec13/31 can self-assemble in a stoichiomet... |
12668098 | Crystal structure of the dimeric beta-cyclodextrin complex with 1,12-dodecanediol. | The structure of the complex of beta-cyclodextrin (beta-CD) with 1,12-dodecanediol has been determined at 173 K and refined to a final R=0.0615 based on 22,386 independent reflections. The complex crystallizes in the triclinic space group P1; with a=17.926(4), b=15.399(3), c=15.416(3) A, alpha=103.425(4), beta=113.404(... |
12668467 | Evidence that collagen fibrils in tendons are inhomogeneously structured in a tubelike manner. | The standard model for the structure of collagen in tendon is an ascending hierarchy of bundling. Collagen triple helices bundle into microfibrils, microfibrils bundle into subfibrils, and subfibrils bundle into fibrils, the basic structural unit of tendon. This model, developed primarily on the basis of x-ray diffract... |
12668466 | Penton release from P22 heat-expanded capsids suggests importance of stabilizing penton-hexon interactions during capsid maturation. | Bacteriophage assembly frequently begins with the formation of a precursor capsid that serves as a DNA packaging machine. The DNA packaging is accompanied by a morphogenesis of the small round precursor capsid into a large polyhedral DNA-containing mature phage. In vitro, this transformation can be induced by heat or c... |
12668465 | X-ray diffraction characterization of the dense phases formed by nucleosome core particles. | Multiple dense phases of nucleosome core particles (NCPs) were formed in controlled ionic conditions (15-160 mM monovalent salt, no divalent ions), under osmotic pressures ranging from 4.7 x 10(5) to 2.35 x 10(6) Pa. We present here the x-ray diffraction analysis of these phases. In the lamello-columnar phase obtained ... |
12668464 | Sedimentation velocity analysis of flexible macromolecules: self-association and tangling of amyloid fibrils. | A novel bead modeling technique has been developed for the analysis of the sedimentation velocity behavior of flexible fibrils. The method involves the generation of a family of bead models representing a sample of the conformations available to the molecule and the calculation of the sedimentation coefficients of thes... |
12668462 | The endogenous calcium ions of horseradish peroxidase C are required to maintain the functional nonplanarity of the heme. | Horseradish peroxidase C (HRPC) binds 2 mol calcium per mol of enzyme with binding sites located distal and proximal to the heme group. The effect of calcium depletion on the conformation of the heme was investigated by combining polarized resonance Raman dispersion spectroscopy with normal coordinate structural decomp... |
12668461 | Reorientational dynamics of enzymes adsorbed on quartz: a temperature-dependent time-resolved TIRF anisotropy study. | The preservation of enzyme activity and protein binding capacity upon protein adsorption at solid interfaces is important for biotechnological and medical applications. Because these properties are partly related to the protein flexibility and mobility, we have studied the internal dynamics and the whole-body reorienta... |
12668460 | Energy transfer pathways in the minor antenna complex CP29 of photosystem II: a femtosecond study of carotenoid to chlorophyll transfer on mutant and WT complexes. | The energy transfer processes between carotenoids and Chls have been studied by femtosecond transient absorption in the CP29-WT complex, which contains only two carotenoids per polypeptide located in the L1 and L2 sites, and in the CP29-E166V mutant in which only the L1 site is occupied. The comparison of these two sam... |
12668459 | Chlorophyll b to chlorophyll a energy transfer kinetics in the CP29 antenna complex: a comparative femtosecond absorption study between native and reconstituted proteins. | The energy transfer processes between Chls b and Chls a have been studied in the minor antenna complex CP29 by femtosecond transient absorption spectroscopy. Two samples were analyzed: the native CP29, purified from higher plants, and the recombinant one, reconstituted in vitro with the full pigment complement. The mea... |
12668458 | High-performance photovoltaic behavior of oriented purple membrane polymer composite films. | The photovoltaic behavior of films in which bacteriorhodopsin molecules are embedded in a polyvinyl alcohol matrix has been investigated by using both pulsed laser excitation and regular light illumination. Response times as short as milliseconds, photocurrents as great as 120 micro A/cm(2), and photovoltages as large ... |
12668449 | Puroindolines form ion channels in biological membranes. | Wheat seeds contain different lipid binding proteins that are low molecular mass, basic and cystine-rich proteins. Among them, the recently characterized puroindolines have been shown to inhibit the growth of fungi in vitro and to enhance the fungal resistance of plants. Experimental data, using lipid vesicles, suggest... |
12668437 | Molecular dynamics simulations of the NGF-TrkA domain 5 complex and comparison with biological data. | The nerve growth factor (NGF) is an important pharmacological target for Alzheimer's and other neurodegenerative diseases. Its action derives partly from its binding to the tyrosine kinase A receptor (TrkA). Here we study energetics and dynamics of the NGF-TrkA complex by carrying out multinanosecond molecular dynamics... |
12668435 | Structural modeling extends QSAR analysis of antibody-lysozyme interactions to 3D-QSAR. | This work shows that quantitative multivariate modeling is an emerging possibility for unraveling protein-protein interactions using a combination of designed mutations with sequence and structure information. Using this approach, it is possible to stereochemically determine which residue properties contribute most to ... |
12668433 | Energetics and self-assembly of amphipathic peptide pores in lipid membranes. | We present a theoretical study of the energetics, equilibrium size, and size distribution of membrane pores composed of electrically charged amphipathic peptides. The peptides are modeled as cylinders (mimicking alpha-helices) carrying different amounts of charge, with the charge being uniformly distributed over a hydr... |
12668431 | Forced detachment of the CD2-CD58 complex. | The force-induced detachment of the adhesion protein complex CD2-CD58 was studied by steered molecular dynamics simulations. The forced detachment of CD2 and CD58 shows that the system can respond to an external force by two mechanisms, which depend on the loading rate. At the rapid loading rates of 70 and 35 pN/ps (pu... |
12665577 | Molecular dissection of a yeast septin: distinct domains are required for septin interaction, localization, and function. | The septins are a family of cytoskeletal proteins present in animal and fungal cells. They were first identified for their essential role in cytokinesis, but more recently, they have been found to play an important role in many cellular processes, including bud site selection, chitin deposition, cell compartmentalizati... |
12665357 | Thermically and electrochemically induced isomerization of a (bis(ferrocene)-cyclam)copper(II) complex. | The new bis(ferrocene)-cyclam macrocycle 1,8-bis(ferrocenylmethyl)-1,4,8,11-tetraazacyclotetradecane, denoted L, has been synthesized. Two Cu(II) complexes with L have been isolated and characterized from X-ray structure determination and electrochemical studies. These two LCu(II) complexes correspond to the type I (fe... |
12665356 | Unusual aryl-porphyrin rotational barriers in peripherally crowded porphyrins. | Previous studies of 5,10,15,20-tetraarylporphyrins have shown that the barrier for meso aryl-porphyrin rotation (DeltaG++(ROT)) varies as a function of the core substituent M and is lower for a small metal (M = Ni) compared to a large metal (M = Zn) and for a dication (M = 4H(2+)) versus a free base porphyrin (M = 2H).... |
12665353 | Lanthanide-transition heterometallic extended structures with novel orthogonal metalloligand as building block. | One-dimensional lanthanide-transition heterometallic chains of squares, [LnNi(2)L(3)(HL)(DMF)(4)(ClO(4))(4).S]( infinity ) (Ln = Gd and Tb; HL is the Schiff base obtained by the condensation of 2-pyridylaldehyde with isonicotinic hydrazide N-oxide; S = solvent) and [LnNi(2)L(4)(DMF)(4)(ClO(4))(3).S]( infinity ) (Ln = D... |
12665343 | Enhancement of the phosphorescence of organic luminophores upon interaction with a mercury trifunctional Lewis acid. | The interaction of the trinuclear mercury(II) complex [(o-C(6)F(4)Hg)(3)] (1) and pyrene leads to the formation of the 1:1 adduct 1.pyrene. The crystal structure of this adduct reveals the existence of supramolecular stacks in which molecules of 1 and molecules of pyrene alternate along the infinite chains. Steady-stat... |
12662296 | Altered proximal T-cell receptor signalling events in mouse CD4+ T cells in the presence of anti-CD4 monoclonal antibodies: evidence for reduced phosphorylation of Zap-70 and LAT. | Anti-CD4 monoclonal antibodies are potential therapeutic agents for the prevention of autoimmune disease and treatment of rejection after organ transplantation and are capable of both restoring tolerance to self-antigens and inducing tolerance to antigens introduced under the cover of the antibody therapy in vivo. Tole... |
12663797 | Viral persistence alters CD8 T-cell immunodominance and tissue distribution and results in distinct stages of functional impairment. | Chronic viral infections often result in ineffective CD8 T-cell responses due to functional exhaustion or physical deletion of virus-specific T cells. However, how persisting virus impacts various CD8 T-cell effector functions and influences other aspects of CD8 T-cell dynamics, such as immunodominance and tissue distr... |
12663789 | Complexes of poliovirus serotypes with their common cellular receptor, CD155. | Structures of all three poliovirus (PV) serotypes (PV1, PV2, and PV3) complexed with their cellular receptor, PV receptor (PVR or CD155), were determined by cryoelectron microscopy. Both glycosylated and fully deglycosylated CD155 exhibited similar binding sites and orientations in the viral canyon for all three PV ser... |
12663788 | Interactions between papillomavirus L1 and L2 capsid proteins. | The human papillomavirus (HPV) capsid consists of 360 copies of the major capsid protein, L1, arranged as 72 pentamers on a T=7 icosahedral lattice, with substoichiometric amounts of the minor capsid protein, L2. In order to understand the arrangement of L2 within the HPV virion, we have defined and biochemically chara... |
12663770 | Human papillomavirus type 16 L1 capsomeres induce L1-specific cytotoxic T lymphocytes and tumor regression in C57BL/6 mice. | We analyzed capsomeres of human papillomavirus type 16 (HPV16) consisting of the L1 major structural protein for their ability to trigger a cytotoxic T-cell (CTL) response. To this end, we immunized C57BL/6 mice and used the L1(165-173) peptide for ex vivo restimulation of splenocytes prior to analysis ((51)Cr release ... |
12663761 | Homo-oligomerization of the porcine reproductive and respiratory syndrome virus nucleocapsid protein and the role of disulfide linkages. | As a step toward understanding the assembly pathway of the porcine reproductive and respiratory syndrome virus (PRRSV), the oligomeric properties of the nucleocapsid (N) protein were investigated. In this study, we have demonstrated that under nonreducing conditions the N protein forms disulfide-linked homodimers. Howe... |
12663758 | Subcellular localization of feline immunodeficiency virus integrase and mapping of its karyophilic determinant. | Feline immunodeficiency virus (FIV), like other members of the lentivirus subfamily, such as human immunodeficiency virus type 1 (HIV-1), can infect nondividing and terminally differentiated cells. The transport of the preintegration complex into the nucleus is cell cycle-independent, but the mechanism is not well unde... |
12662041 | Self-assembly of novel [3]- and [2]rotaxanes based on donor-acceptor and hydrogen-bonding interactions. Intensified inter-ring repulsion interaction and shuttling behavior. | Three novel hetero[3]rotaxanes, which comprise one neutral tetraamide cyclophane, one tetracationic cyclophane, and one linear component, have been assembled by utilizing hydrogen-bonding and donor-acceptor interactions, through three neutral [2]rotaxanes as intermediates. Three tetracationic [2]rotaxanes are also prep... |
12662039 | Nitrosation of 2-acetylcyclohexanone. 2. Reaction in water in the absence and presence of cyclodextrins. | The kinetic study of the nitrosation of the enol of 2-acetylcyclohexanone (ACHE) has been performed in aqueous acid media in the absence and presence of alpha- and beta-cyclodextrin. The reaction is first-order with respect to both reactants concentration: [nitrite] and [ACHE]; but, unexpectly, the dependence of both [... |
12662024 | Host-[2]rotaxane: advantage of converging functional groups for guest recognition. | A host-[2]rotaxane was constructed by converting a diaminophenylcalix[4]arene into a [2]rotaxane using the DCC-rotaxane method (Zehnder, D.; Smithrud, D. B. Org. Lett. 2001, 16, 2485-2486). N-Ac-Arg groups were attached to the dibenzo-24-crown-8 ring of the rotaxane to provide a convergent functional group. To demonstr... |
12662023 | Structure-function relationship of amino acid-[2]rotaxanes. | Synthetic methodology was developed to construct amino acid-[2]rotaxanes that have phenylalanine and 3,5-di-tert-butylbenzene as blocking groups and dibenzo-24-crown-8, derivatized with either N-acetylargininyl or a carboxylic group, as the ring. A relative measure of the intramolecular interaction energies between the... |
12659898 | Near infrared spectral investigations of hydration of 18-crown-6 in HDO-D2O solutions at different temperatures. | Near infrared spectra of solution of 6.4 M HDO in D(2)O have been obtained at 15, 25, 30, and 35 degrees C. It was observed that the bands of HDO in D(2)O occur at 1416, 1525, 1556, and 1666 nm, which are in good agreement with the similar data reported earlier by Worley and Klotz. The calculations of enthalpy change f... |
12659885 | Raman spectroscopic investigation of the single-monolayer Langmuir-Blodgett film of C16NaphOH and C10AzoNaphC4N-SDS. | Raman spectra were measured for Langmuir-Blodgett (LB) films of C(16)NaphOH and C(10)AzoNaphC(4)N-SDS on Calcium Fluorite substrate for the first time. In order to find out favorable excitation condition, Raman spectra of the single and multi-monolayer LB films excited at different lines at 244, 514, 633 and 778 nm are... |
12659592 | Weak C-H/pi interaction participates in the diastereoselectivity of a host-guest complex in the presence of six strong hydrogen bonds. | [structure: see text] We report a study of the interaction between methylmethanetriacetic acid (MMTA) and a tripodal amidopyridine receptor 1, where the geometry of the binding is in part governed by a weak C-H/pi interaction in the presence of six strong N(O)-H.O(N) hydrogen bonds. There are two possible binding geome... |
12659588 | Intramolecular syn and anti hydrosilylation and silicon-assisted cross-coupling: highly regio- and stereoselective synthesis of trisubstituted allylic alcohols. | [reaction: see text] The geometrical isomers of 6-ethylidenedioxadisilacyclohexane were prepared by intramolecular hydrosilylation of an unsymmetrical disiloxane by the use of Pt (syn) and Ru (anti) catalysts. This new class organosilicon reagents underwent cross-coupling reactions with a range of aryl iodides to affor... |
12659576 | Multipoint molecular recognition of amino acids and biogenic amines by ureidocalix[5]arene receptors. | [reaction: see text] p-tert-Butylcalix[5]arenes in a fixed cone conformation, endowed with a urea functionality at the upper rim, behave as remarkably efficient abiotic receptors of omega-amino acids and biogenic amines, which are bound with one end of the chain within the pi-basic cavity (primary recognition site) and... |
12659570 | Short and diverse route toward complex natural product-like macrocycles. | [reaction: see text] A general strategy toward macrocyclic compounds using multicomponent reaction (MCR) chemistry, e.g., Passerini and Ugi variants, and ring-closing metathesis (RCM) is introduced. The corresponding bifunctional isocyanides carboxylic acids bearing a terminal olefin are easy to prepare from the corres... |
12640443 | A HEX-1 crystal lattice required for Woronin body function in Neurospora crassa. | The Woronin body is a dense-core vesicle specific to filamentous ascomycetes (Euascomycetes), where it functions to seal the septal pore in response to cellular damage. The HEX-1 protein self-assembles to form this solid core of the vesicle. Here, we solve the crystal structure of HEX-1 at 1.8 A, which provides the str... |
12661077 | Improved aqueous solubility of crystalline astaxanthin (3,3'-dihydroxy-beta, beta-carotene-4,4'-dione) by Captisol (sulfobutyl ether beta-cyclodextrin). | Carotenoids are the most widely distributed natural pigments, with over 600 individual compounds identified and characterized from natural sources. A few are commercially important molecules, having found utility as additions to animal feed in the aquaculture, poultry, and swine feed industries. The majority are lipoph... |
12659750 | Synthesis, cellular internalization and photodynamic activity of glucoconjugated derivatives of tri and tetra(meta-hydroxyphenyl)chlorins. | Glucoconjugated tri and tetra(meta-hydroxyphenyl)chlorins have been synthesized in order to explore how glucoconjugation of the macrocycle affects the photoactivity of the molecule. Internalization processes, photosensitizing efficacy of TPC(m-O-GluOH)(3) and TPC(m-O-GluOH)(4), in HT29 human adenocarcinoma cells have b... |
12657914 | Chiral analysis of d- and l-modafinil in human serum: application to human pharmacokinetic studies. | Modafinil is a novel stimulant approved by the FDA for use in the management of excessive sleepiness associated with narcolepsy. Utility for other indications includes attention deficit-hyperactivity disorder (ADHD), depression, and management of cocaine dependence. To investigate the pharmacokinetics of modafinil in t... |
12656627 | Mapping the influence of molecular structure on rates of electron transfer using direct measurements of the electron spin-spin exchange interaction. | The spin-spin exchange interaction, 2J, in a radical ion pair produced by a photoinduced electron transfer reaction can provide a direct measure of the electronic coupling matrix element, V, for the subsequent charge recombination reaction. We have developed a series of dyad and triad donor-acceptor molecules in which ... |
12656625 | Luminescent CdSe/CdS core/shell nanocrystals in dendron boxes: superior chemical, photochemical and thermal stability. | The surface ligands, generation-3 (G3) dendrons, on each semiconductor nanocrystal were globally cross-linked through ring-closing metathesis (RCM). The global cross-linking of the dendron ligands sealed each nanocrystal in a dendron box, which yielded box-nanocrystals. Although the dendron ligands coated CdSe nanocrys... |
12656618 | Sanglifehrin-cyclophilin interaction: degradation work, synthetic macrocyclic analogues, X-ray crystal structure, and binding data. | Sanglifehrin A (SFA) is a novel immunosuppressive natural product isolated from Streptomyces sp. A92-308110. SFA has a very strong affinity for cyclophilin A (IC(50) = 6.9 +/- 0.9 nM) but is structurally different from cyclosporin A (CsA) and exerts its immunosuppressive activity via a novel mechanism. SFA has a comple... |
12656595 | Bimetallic palladium-platinum dendrimer-encapsulated catalysts. | We report the synthesis, characterization, and catalytic activity of bimetallic palladium-platinum dendrimer-encapsulated catalysts (DECs). These materials are prepared by co-complexation of different ratios of palladium and platinum salts to the interior tertiary amines of fourth-generation, hydroxyl-terminated poly(a... |
12658658 | Shape-controlled bridged silsesquioxanes: hollow tubes and spheres. | A new approach for the morphological control of bridged silsesquioxanes has been achieved by the hydrolysis of silylated organic molecules bearing urea groups. The urea groups are responsible for the auto-association of the molecules through intermolecular hydrogen-bonding interactions. The self-assembly leads to supra... |
12658651 | Quantitative comparison of kinetic stabilities of metallomacrocycle-based rotaxanes. | Four mononuclear metallomacrocycles with identical cavities but different transition metals (Os(VI), Pd(II), Pt(II), and Re(I)) were prepared. With these metallomacrocycles, the corresponding rotaxanes 2-Os, 2-Pd, 2-Pt, and 2-Re were self-assembled by hydrogen-bonding interactions. The kinetic stabilities of the rotaxa... |
12658643 | High-pressure structural trends of Group 15 elements: simple packed structures versus complex host-guest arrangements. | The Group 15 elements P, As, Sb, and Bi all have layered structures consisting of six-membered rings under ambient conditions and attain the body-centered cubic (bcc) structure at the highest pressures applied. In the intermediate pressure region, however, phosphorus and its heavier congeners behave profoundly differen... |
12658642 | Macrocycles from perhalogenated heterocycles. | Perhalogenated heteroaromatic systems, such as trichloro-s-triazine and pentafluoropyridine, are multifunctional "building blocks" that react with a number of appropriate difunctional nucleophiles to provide access to a variety of macrocyclic and even cage-like molecular architectures. Unusual structural and complexati... |
12655009 | Molecular recognition properties of IGS-mediated reactions catalyzed by a Pneumocystis carinii group I intron. | We report the development, analysis and use of a new combinatorial approach to analyze the substrate sequence dependence of the suicide inhibition, cyclization, and reverse cyclization reactions catalyzed by a group I intron from the opportunistic pathogen Pneumocystis carinii. We demonstrate that the sequence specific... |
12655002 | AINTEGUMENTA utilizes a mode of DNA recognition distinct from that used by proteins containing a single AP2 domain. | The Arabidopsis protein AINTEGUMENTA (ANT) is an important regulator of organ growth during flower development. ANT is a member of the AP2 subclass of the AP2/ERF family of plant-specific transcription factors. These proteins contain either one or two copies of a DNA-binding domain called the AP2 domain. Here, it is sh... |
12654822 | Helicobacter pylori mutants defective in RuvC Holliday junction resolvase display reduced macrophage survival and spontaneous clearance from the murine gastric mucosa. | Homologous recombination contributes to the extraordinary genetic diversity of Helicobacter pylori and may be critical for surface antigen expression and adaptation to environmental challenges within the stomach. We generated isogenic, nonpolar H. pylori ruvC mutants to investigate the function of RuvC, a Holliday junc... |
12655653 | Effect of anti-CD20 monoclonal antibody, Rituxan, on cynomolgus monkey and human B cells in a whole blood matrix. | <h4>Background</h4>Cynomolgus monkeys are widely used animal models in biomedical research. The differences between cynomolgus monkey and human B cells are not completely understood. However, these differences are of crucial importance for interpretation of data from studies on new therapeutic agents aimed at B-cell de... |
12654692 | Efficacy of micafungin alone or in combination against systemic murine aspergillosis. | We tested the efficacy of micafungin (FK) alone or in combination with other antifungals against systemic murine aspergillosis. FK alone at 10 mg/kg of body weight/dose prolonged survival (P = 0.01) and reduced CFU in the brain and kidney. Combination therapy that used suboptimal FK with amphotericin B or itraconazole ... |
12654687 | Activity of posaconazole against Pseudallescheria boydii: in vitro and in vivo assays. | Thirty isolates of Pseudallescheria boydii were tested to compare the in vitro activity of posaconazole with those of fluconazole and itraconazole, using NCCLS methods. Posaconazole was evaluated in an immunosuppressed mouse model of disseminated pseudallescheriasis. Posaconazole was more effective than itraconazole an... |
12651630 | Switch moiety in agonist/antagonist dual effect of S19 ribosomal protein dimer on leukocyte chemotactic C5a receptor. | The cross-linked homodimer of S19 ribosomal protein (RP S19) induces monocyte predominant infiltration due to a dual effect on the C5a receptor in leukocyte chemotaxis, agonistic to monocytes and antagonistic to polymorphonuclear leukocytes (PMN) (H. Nishiura, Y. Shibuya, T. Yamamoto, Lab Invest 1998, 78:1615-1623). Th... |
12649445 | Analyses of circular dichroism spectra of membrane proteins. | Circular dichroism (CD) spectroscopy is a valuable technique for the determination of protein secondary structures. Many linear and nonlinear algorithms have been developed for the empirical analysis of CD data, using reference databases derived from proteins of known structures. To date, the reference databases used b... |
12649431 | Using nondenaturing mass spectrometry to detect fortuitous ligands in orphan nuclear receptors. | Nondenaturing electrospray mass spectrometry (ESI-MS) has been used to reveal the presence of potential ligands in the ligand-binding domain (LBD) of orphan nuclear receptors. This new approach, based on supramolecular mass spectrometry, allowed the detection and identification of fortuitous ligands for the retinoic ac... |
12485116 | Positive and negative regulation of T-cell activation through kinases and phosphatases. | The sequence of events in T-cell antigen receptor (TCR) signalling leading to T-cell activation involves regulation of a number of protein tyrosine kinases (PTKs) and the phosphorylation status of many of their substrates. Proximal signalling pathways involve PTKs of the Src, Syk, Csk and Tec families, adapter proteins... |
12643772 | K+ and Na+-induced self-assembly of telomeric oligonucleotide d(TTAGGG)n. | The telomeric DNA oligomers, d(TTAGGG)(n), where n=1, 2, 4, could self-associate into the multi-stranded structures in appropriate condition, exhibited different CD spectra. The presense of Na(+) was more advantage to facilitate the formation of anti-parallel conformation, but the presense of K(+) enhanced their therma... |
12643764 | Molecular dynamics simulations of the unfolding of the starch binding domain from Aspergillus niger glucoamylase. | The 600 ps molecular dynamics simulations to investigate the unfolding of the starch binding domain from Aspergillus niger glucoamylase were conducted in vacuum as well as in an external field with the dielectric constant of 80 with temperature jump technique. Electrostatic interactions play an important role in determ... |
12644498 | Mutations which uncouple transport and phosphorylation in the D-mannitol phosphotransferase system of Escherichia coli K-12 and Klebsiella pneumoniae 1033-5P14. | Mutants of Escherichia coli K-12 were isolated which lack the normal phosphotransferase system-dependent catabolic pathway for D-mannitol (Mtl). In some mutants the pts genes for the general proteins enzyme I and histidine protein of the phosphoenolpyruvate-dependent carbohydrate phosphotransferase systems were deleted... |
12644494 | Differential expression of the Escherichia coli autoaggregation factor antigen 43. | Antigen 43 (Ag43) is a self-recognizing surface adhesin found in most Escherichia coli strains. Due to its excellent cell-to-cell aggregation characteristics, Ag43 expression confers clumping and fluffing of cells and promotes biofilm formation. Ag43 expression is repressed by the cellular redox sensor OxyR. Here we us... |
12644485 | Metabolic enzymes from psychrophilic bacteria: challenge of adaptation to low temperatures in ornithine carbamoyltransferase from Moritella abyssi. | The enzyme ornithine carbamoyltransferase (OTCase) of Moritella abyssi (OTCase(Mab)), a new, strictly psychrophilic and piezophilic bacterial species, was purified. OTCase(Mab) displays maximal activity at rather low temperatures (23 to 25 degrees C) compared to other cold-active enzymes and is much less thermoresistan... |
12640129 | Supramolecular complex formation between Rad6 and proteins of the p53 pathway during DNA damage-induced response. | The HR6A and -B genes, homologues of the yeast Rad6 gene, encode ubiquitin-conjugating enzymes that are required for postreplication repair of DNA and damage-induced mutagenesis. Using surface plasmon resonance, we show here that HR6 protein (referred as Rad6) physically interacts with p53. Analysis of proteins coimmun... |
12640128 | Involvement of poly(ADP-Ribose) polymerase 1 and poly(ADP-Ribosyl)ation in regulation of centrosome function. | The regulatory mechanism of centrosome function is crucial to the accurate transmission of chromosomes to the daughter cells in mitosis. Recent findings on the posttranslational modifications of many centrosomal proteins led us to speculate that these modifications might be involved in centrosome behavior. Poly(ADP-rib... |
12637642 | Outcome in a post-cardiac surgery population with acute renal failure requiring dialysis: does age make a difference? | <h4>Background</h4>Acute renal failure (ARF), requiring dialysis (ARF-d), develops in 1-5% of patients undergoing cardiac surgery and is associated with higher in-hospital mortality. Age is one of the known risk factors for the development of ARF. As the ageing population is increasing, the nephrologist will be faced w... |
12628314 | Violacein and its beta-cyclodextrin complexes induce apoptosis and differentiation in HL60 cells. | Violacein, a pigment isolated from Chromobacterium violaceum, has been reported to have multiple biological activities including in vitro antitumor effects. Certain anticancer agents are known to induce apoptosis in human tumor cell lines. In this work, our aim was to investigate the effectiveness of violacein/beta-cyc... |
12604266 | High sensitivity detection of molecular recognition using magnetically labelled biomolecules and magnetoresistive sensors. | Small magnetoresistive spin valve sensors (2 x 6 microm(2)) were used to detect the binding of single streptavidin functionalized 2 microm magnetic microspheres to a biotinylated sensor surface. The sensor signals, using 8 mA sense current, were in the order of 150-400 microV for a single microsphere depending on senso... |
12586142 | Supramolecular interactions of humic acids with organic and inorganic xenobiotics studied by capillary electrophoresis. | Methodology based on capillary electrophoresis (CE) to study humic acids (HAs)-xenobiotics interactions is proposed. The interactions of HAs with organic and inorganic xenobiotics like paraquat, diquat, p,p(')-DDE, p,p(')-DDT, potassium ferrocyanide, potassium ferricyanide, chloride, 4-nitrocatechol and other organic c... |
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