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9788953 | Location of fluorotryptophan sequestered in an amphiphilic nanoparticle by rotational-echo double-resonance NMR. | Rotational-echo double-resonance (REDOR) 13C NMR spectra (with 19F dephasing) have been obtained of 6-fluorotryptophan complexed by a polymeric amphiphilic nanosphere consisting of a polystyrene core covalently attached to a poly(acrylic acid)-polyacrylamide shell. The REDOR spectra show that aromatic carbons from the ... |
9788942 | Molecular origins of osmotic second virial coefficients of proteins. | The thermodynamic properties of protein solutions are determined by the molecular interactions involving both solvent and solute molecules. A quantitative understanding of the relationship would facilitate more systematic procedures for manipulating the properties in a process environment. In this work the molecular ba... |
9788930 | A neutron reflectivity study of polymer-modified phospholipid monolayers at the solid-solution interface: polyethylene glycol-lipids on silane-modified substrates. | The structure of polymer-decorated phospholipid monolayers at the solid-solution interface was investigated using neutron reflectometry. The monolayers were composed of distearoylphosphatidylethanolamine (DSPE) matrixed with varying amounts of DSPE-PEG (DSPE with polyethylene glycol covalently grafted to its headgroup)... |
9788917 | Simultaneous height and adhesion imaging of antibody-antigen interactions by atomic force microscopy. | Specific molecular recognition events, detected by atomic force microscopy (AFM), so far lack the detailed topographical information that is usually observed in AFM. We have modified our AFM such that, in combination with a recently developed method to measure antibody-antigen recognition on the single molecular level ... |
9787000 | Intradermal injection of capsaicin in humans produces degeneration and subsequent reinnervation of epidermal nerve fibers: correlation with sensory function. | The ability of capsaicin to excite and subsequently to desensitize a select group of small sensory neurons has made it a useful tool to study their function. For this reason, application of capsaicin to the skin has been used for a variety of painful syndromes. We examined whether intradermal injection of capsaicin pro... |
9784519 | Immunological characterization of Asp f 2, a major allergen from Aspergillus fumigatus associated with allergic bronchopulmonary aspergillosis. | The 37-kDa recombinant protein Asp f 2, encoding an allergen of Aspergillus fumigatus, was expressed in a prokaryotic expression system and immunologically evaluated for its functional and structural properties. The open reading frame for a 310-amino-acid-long protein was shown to encode a signal peptide of 31 amino ac... |
9765472 | The bipartite geminivirus coat protein aids BR1 function in viral movement by affecting the accumulation of viral single-stranded DNA. | The movement of bipartite geminiviruses such as squash leaf curl virus (SqLCV) requires the cooperative interaction of two essential virus-encoded movement proteins, BR1 and BL1. While the viral coat protein AR1 is not essential for systemic infection, genetic studies demonstrate that its presence masks the defective p... |
29711632 | Crystal Structure of a Peptide-Steroid Macrocycle-Intramolecular Attraction between Steroids and Peptidic β(I) Turns. | Two molecules of the steroid lithocholic acid and two dipeptides (Phe-Phe) make up the macrocycle 1, in which the two steroidal surfaces approach each other so that the peptide parts fold into β(I) turns. Thus, the structure of a cyclic steroid-peptide compound was determined in the solid state for the first time. The ... |
29711626 | The Binding of Sulfate Anions by Guanidinium Receptors is Entropy-Driven. | Clear trends in the molecular recognition of guest species by artificial hosts in solution are often observed by intrinsic enthalpy-entropy compensation, which requires the dissection of these free-energy components. Contrary to common belief, it is not the enthalpic electrostatic attraction that makes guanidinium host... |
29711622 | Investigations into the Manzamine Alkaloid Biosynthetic Hypothesis. | The biomimetic synthesis of a pentacyclic alkaloid (keramaphidin B, 1), an intermediate in the biogenetic pathway to the manzamine alkaloids, has been achieved. Compound 1 was formed by an intramolecular Diels-Alder reaction of macrocycle 2 in buffer followed by reduction with NaBH<sub>4</sub> . This reaction provides ... |
29711612 | Calixarene-Based Copper(I) Complexes as Models for Monocopper Sites in Enzymes. | A cavity that acts as a molecular funnel is formed from calix[6]arene 1 and [Cu<sup>I</sup> (NCCH<sub>3</sub> )<sub>4</sub> ]PF<sub>6</sub> [Eq. (a)]. An exchange of the well-protected acetonitrile ligand for other nitriles RCN is only possible with small R groups. The protection of the copper ions precludes oxidative ... |
29711606 | Site-Directed Surface Derivatization of MCM-41: Use of High-Resolution Transmission Electron Microscopy and Molecular Recognition for Determining the Position of Functionality within Mesoporous Materials. | The "staining" cluster-crown compound [Ru<sub>6</sub> C(CO)<sub>14</sub> (η<sup>6</sup> -C<sub>6</sub> H<sub>4</sub> C<sub>10</sub> H<sub>20</sub> O<sub>6</sub> )] verifies that the internal walls of mesoporous silica MCM-41 may be selectively functionalized with propylammonium groups (see picture). By the use of high-... |
29711359 | Towards a Rational Synthesis of Large-Pore Zeolite-Type Materials? | A range of novel structures, such as the metalloaluminosilicate UCSB-8 (depicted schematically), are accessible by synthetic strategies that could provide the basis for the rational design of other large-pore zeolites and zeolite-type materials. The combination of experimental approaches with computational methods, for... |
29711354 | Self-Organization and Formation of Liquid Crystal Phases by Molecular Templates Related to Membrane Components of Archaebacteria. | Tubular supramolecular aggregates are formed from glycolipids 1, which are closely related to natural components of membranes of archaebacteria. The glycolipids exhibit disordered columnar thermotropic and hexagonal lyotropic liquid crystal phases. Whereas formation of the mesophases is insensitive to stereochemical fa... |
29711353 | Extended Calixpyrroles: meso-Substituted Calix[6]pyrroles. | A 1,3,5-alternate conformation of the pyrrole rings is adopted by the calix[6]pyrrole 1 in the crystal (see picture). Compound 1 was synthesized in a two-step process and although it crystallizes in the form of the adduct 1⋅3CH<sub>3</sub> COCH<sub>3</sub> ⋅H<sub>2</sub> O⋅CHCl<sub>3</sub> , there are no solvent molecu... |
21651251 | Electrochemistry of tert-Butylcalix[8]arene-C(60) Films Using a Scanning Electrochemical Microscope-Quartz Crystal Microbalance. | The electrochemical reduction of tert-butylcalix[8]arene-C(60) particle films was studied using the scanning electrochemical microscope combined with a quartz crystal microbalance (QCM) for several electrolytes in MeCN. Complexation of the fullerene within the film results in a negative shift of the peak potential of t... |
21651240 | Capillary electrophoresis with electrochemical detection for chiral separation of optical isomers. | The enantiomers of two amine derivatives were directly separated by capillary electrophoresis (CE), employing β-cyclodxtrin (β-CD) as a chiral additive in strongly alkaline solutions. The analytes were detected by electrochemistry, using a copper disk electrode at +675 mV vs Ag/AgCl reference electrode. Both the free e... |
10837670 | Nuclear import of polypeptides, polynucleotides and supramolecular complexes. | Nuclear import of macromolecules or particles is a strictly regulated phenomenon that is now understood in some depth at the molecular level. Transport across nuclear membranes is controlled by nuclear pores, with the involvement of cytoplasmic receptors and accessory molecules. Each nuclear pore complex is an assembly... |
9794754 | Strong enhancement of nonlinear optical properties through supramolecular chirality | A new approach to second-order nonlinear optical (NLO) materials is reported, in which chirality and supramolecular organization play key roles. Langmuir-Blodgett films of a chiral helicene are composed of supramolecular arrays of the molecules. The chiral supramolecular organization makes the second-order NLO suscepti... |
9789086 | A photosystem I reaction center driven by chlorophyll d in oxygenic photosynthesis. | A far-red type of oxygenic photosynthesis was discovered in Acaryochloris marina, a recently found marine prokaryote that produces an atypical pigment chlorophyll d (Chl d). The purified photosystem I reaction center complex of A. marina contained 180 Chl d per 1 Chl a with PsaA-F, -L, -K, and two extra polypeptides. L... |
11672391 | Synthesis of Mixed Thiophene/Furan Oligomers by Stille Coupling. | A series of mixed thiophene/furan oligomers have been synthesized via organometallic Stille coupling. In some cases, beside cross-coupling products, symmetrical coupling products were isolated. Oligomers consisting of up to 11 rings were obtained. Attempts to prepare macrocycles with 10 thiophene and furan units were n... |
11672353 | A New, Aqueous (1)H NMR Shift Reagent Based on Host-Guest Molecular Recognition Principles for Organic Compound Structural Analysis: Non-covalent pi-pi and Hydrophobic Interactions Using a Supramolecular Host, [CpRh(2'-deoxyadenosine)](3)(OTf)(3). | We have discovered that the supramolecular host [CpRh(2'-deoxyadenosine)](3)(OTf)(3) (1, Cp = eta(5)-C(5)Me(5), OTf = CF(3)SO(3)(-)) has utility as a new, aqueous (1)H NMR shift reagent, via a host-guest molecular recognition process that occurs by non-covalent pi-pi and hydrophobic interactions, with a wide variety of... |
11672302 | Water-Soluble Cavitands: Synthesis of Methylene-Bridged Resorcin[4]arenes Containing Hydroxyls and Phosphates at Their Feet and Bromomethyls and Thiomethyls at Their Rims. | The synthesis of rim-functionalized methylene-bridged resorcin[4]arenes ("cavitands") containing hydrophilic propanol or water-solublilizing propylphosphate feet is described. The cavitands possess the synthetically useful benzylthiol (cavitands 6 and 16) or benzylbromide (cavitands 9 and 11) functionalities at their r... |
11670709 | Self-Assembling Synthesis of Cyclic Tri- and Tetranuclear Cobalt(III) Complexes Bridged by Purine-6-thione and Their Characterization by Electrospray Mass Spectrometry and X-ray Crystal Analysis. | The cyclic multinuclear complexes [Co(n)()(L-N,S,N')(n)()(tacn)(n)()](n)()(+) (L = purine-6-thiones; tacn = 1,4,7-triazacyclononane) were synthesized through self-assembly of the mononuclear complex [Co(HL-N,S)Cl(tacn)](+) based on the multidentate bridging ability of purine-6-thione. Three kinds of purine-6-thione lig... |
11670707 | Neutral Guest Capture via Lewis Acid/Base Molecular Square Receptors. X-ray Crystal Structure of {Cyclobis[(cis-(dppp)Pt(4-ethynylpyridyl)(2))(cis- (PEt(3))(2)Pt)]Ag(2)}(+6)(phenazine)- ((-)OSO(2)CF(3))(6). | Interaction of {cyclobis[(cis-(dppp)Pt(4-ethynylpyridyl)(2))(cis-(L)M)]Ag(2)}(+6)((-)OSO(2)CF(3))(6), where M = Pt(II) or Pd(II) and L = dppp or 2PEt(3), with pyridine, pyrazine, phenazine, or 4,4'-dipyridyl ketone results in coordination Lewis acid/base host-guest assemblies via the "pi-tweezer effect" and mono or bis... |
11670695 | Unexpectedly Lengthened N-H.Co Hydrogen Bonds? | Low-temperature crystal structures of QuinH(+)Co(CO)(4)(-), 1 (QuinH(+) = quinuclidinium), (DABCO)H(+)Co(CO)(3)P(p-tolyl)(3)(-), 2, and (DABCO)H(+)Co(CO)(3)PPh(2)(p-tolyl)(-), 3 (DABCO = 1,4-diazabicyclooctane), 2 and 3 as their acetonitrile solvates, demonstrate that these salts exhibit intermolecular N-H.Co hydrogen ... |
15825381 | [Phenomena of supramolecular assembly fluid room temperature phosphorescence (II)--effects of alcohols on room temperature phosphorescence of cyclodextrin/4-iodo-4'-ethyl-biphenyl/bromocyclohexane system]. | Beta-cyclodextrin( beta/-CD)can induce 4-iodo-4'-ethyl-biphenyl(IEBP)to emit room temperature phosphorescence(RTP) in the presence of bromocyclohexane (BCH). If butyl alcohol (BuOH) is presented as a fourth component at the same time, RTP intensity of the system is enhanced obviously. Effects of different alcohols, CDs... |
9788898 | The role of reactive oxygen and nitrogen species in airway epithelial gene expression. | The body first encounters deleterious inhaled substances, such as allergens, industrial particles, pollutants, and infectious agents, at the airway epithelium. When this occurs, the epithelium and its resident inflammatory cells respond defensively by increasing production of cytokines, mucus, and reactive oxygen and n... |
10658446 | [Cardiovascular morbidity/mortality modified by the use of FGE1 alpha-cyclodextran and calcium heparin in patients with severe vascular diseases]. | <h4>Background</h4>Morbidity and mortality were evaluated in three groups of vascular patients: one group was treated with PGE1 alpha-ciclodestrina according to the short term protocol; the second group was treated with PGE1 alpha-ciclodestrina and subcutaneous calcium heparin (SCH; 0.5 ml once daily, in the evening) w... |
10658445 | [Reduction of cardiovascular morbidity/mortality in arteriopathies treated ith PGE1 alpha-cyclodextrin]. | <h4>Background</h4>Cardiovascular morbidity and mortality were evaluated in two groups of vascular patients (one treated with PGE1 alpha-ciclodestrina according to the short term protocol and one reference group) with a follow up of at least 24 month.<h4>Methods</h4>The former group included patients who had been treat... |
10658444 | [Circadian variations of cutaneous blood flow in normal subjects and in patients with peripheral arteriopathies. Effect of PGE1 and alpha-cyclodextrin]. | <h4>Background</h4>In this study the circadian skin flux pattern was evaluated in 10 normal reference subjects and in 35 patients (mean age 68 +/- 11) subdivided in groups (10 with intermittent claudication (200-400 m of walking distance), 10 diabetics with claudication, 7 patients with rest pain and 8 with localised g... |
10658443 | [Increasing transcutaneous PO2 in arteriopathies during treatment with PGE1 alpha-cyclodextrin]. | <h4>Background</h4>Transcutaneous PO2 values (at the dorsum of the foot) were evaluated in a group of 8 patients (mean age 66 +/- 11) with critical ischemia including 4 patients (mean age 65 +/- 10) with gangrene[. A group of 5 comparable normal controls was also studied.<h4>Methods</h4>Patients were treated with PGE1 ... |
10658442 | ["Responders and non-responders" to PGE1 and alpha-cyclodextrin]. | <h4>Background</h4>In this study we evaluated a group of 76 patients (mean age 66 +/- 12) treated with the short-term PGE1 alpha-ciclodestrina protocol (60 micrograms/die for 2 days). Responders to PGE1 alpha-ciclodestrina treatment were considered patients with an increase in flow/perfusion and an associated improveme... |
10658441 | [European trial of PGE1 alpha cyclodextrin. Short-term vs. long-term therapy in intermittent claudication]. | <h4>Background</h4>The efficacy, safety and cost of prostaglandin E1 (PGE1 alpha-ciclodestrina) in the treatment of severe intermittent claudication was studied comparing a long term treatment protocol (LTP) with a short term treatment protocol (STP) in a randomised, 20-week study.<h4>Methods</h4>The study has selected... |
10658440 | [Intra-arterial infusion of PGE1 alpha cyclodextrin]. | <h4>Background</h4>Intra-arterial infusion of PGE1 alpha-ciclodestrina was achieved by intrafemoral catheter in critical limb ischemia.<h4>Methods</h4>The acute infusion of 10 micrograms in 20 minutes, in 50 ml of saline was followed by chronic infusion 20 micrograms/die of PGE1 alpha-ciclodestrina for 5 days. Three ma... |
10658439 | [Analysis of costs and results of prostaglandin (PGE1 alpha-cyclodestrin) therapy of peripheral arterial diseases]. | <h4>Background</h4>In this study patients with peripheral vascular disease were treated with PGE1 alpha-ciclodestrina. In the intermittent claudication group (walking distance at inclusion between 200-600 m) we included 55 patients treated with PGE1 alpha-ciclodestrina (15 diabetics) and 22 controls (not treated with P... |
10500770 | Combinatorial libraries: studies in molecular recognition. | In recent years, combinatorial libraries have become a major tool for drug discovery and drug development. Along the way, one potential use of combinatorial chemistry libraries almost been neglected: the basic study of intermolecular interactions. Especially "one-bead-one-structure" libraries can be a powerful means fo... |
10209898 | Chiral determination of amphetamine and related compounds using chloroformates for derivatization and high-performance liquid chromatography. | The enantiomeric determination of amphetamine and various amphetamine-type compounds by liquid chromatography after chiral derivatization with 9-fluorenylmethyl chloroformate-L-proline (FMOC-L-Pro) is reported. The results obtained were compared with those achieved after achiral derivatization with 9-fluorenylmethyl ch... |
9920346 | The cytochrome P450 suicide inhibitor, 1-aminobenzotriazole, sensitizes rats to zymosan-induced toxicity. | Reduction in whole body cytochrome P450 (CYP 450) activity is evident in humans who develop trauma and sepsis-induced multiple organ failure (MOF). It is not known whether this has any deleterious or protective effect. Intraperitoneal injection of zymosan, the cell wall of Saccharomycoses A, induces dose-dependent infl... |
9875485 | Percutaneous absorption and model membrane variations of melatonin in aqueous-based propylene glycol and 2-hydroxypropyl-beta-cyclodextrin vehicles. | Percutaneous absorption and model membrane variations of melatonin (MT) in aqueous-based propylene glycol and 2-hydroxypropyl-beta-cyclodextrin vehicles were investigated. The excised hairless mouse skin (HMS) and two synthetic ethylene vinyl acetate (EVA) and microporous polyethylene (MPE) were selected as a model mem... |
9863956 | Inclusion complex formation of steroidal drugs with hydroxypropyl-beta-cyclodextrin studied by charge-transfer chromatography. | The interaction between 17 steroidal drugs and hyroxypropyl-beta-cyclodextrin (HPbetaBCD) was determined by charge-transfer chromatography and the relative strength of interaction was calculated. HPbetaCD interacted with each steroidal drugs decreasing the hydrophobicity of the guest molecules. The relative strength of... |
9863954 | The equilibrium constant of beta-cyclodextrin-phenolphtalein complex; influence of temperature and tetrahydrofuran addition. | The temperature influence on creation of a supramolecular complex in which beta-cyclodextrin (beta-CD) is the host molecule and phenolphtalein (PP) is the guest has been studied in aqueous solution by UV-visible absorption spectroscopy. The decrease of temperature of beta-cyclodextrin-phenolphtalein system resulted in ... |
9853673 | Structural dissection of the DNA-binding domain of the yeast transcriptional activator GAL4 reveals an alpha-helical region responsible for dimerization. | Limited proteolysis of the DNA-binding domain (residues 1-147) of the yeast transcriptional activator GAL4 has been used to define more precisely the subdomain structure required for DNA binding and dimerization. Two regions of the protein were found to be resistant to proteolysis: the cysteine-rich, zinc-binding regio... |
9839880 | FIV infection of IL-2-dependent and -independent feline lymphocyte lines: host cells range distinctions and specific cytokine upregulation. | We have analyzed the ability of three molecular clones of feline immunodeficiency virus (FIV) and an ex vivo variant to infect nine distinct specific-pathogen-free feline cell lines in tissue culture. The purpose of these studies was to elucidate mechanisms by which host cells regulate the level of virus infection and ... |
9832305 | Molecular recognition of cobalt(III)-ligated peptides by serine proteases: the role of electrostatic effects. | A series of peptides with a positively charged cobalt(III)-complex group attached to the carboxylate terminal was synthesized. The behavior of these metallopeptides as acceptor nucleophiles in acyl transfer reactions catalyzed by the three serine proteases bovine pancreatic alpha-chymotrypsin, porcine pancreatic trypsi... |
9828462 | Effects of mutations in the starch-binding domain of Bacillus macerans cyclodextrin glycosyltransferase. | Cyclodextrin glycosyltransferase (CGTase) is an industrially important enzyme that produces cyclodextrins (CD) from starch by intramolecular transglycosylation. CGTase consists of five globular domains labeled A through E. To better understand the role of domain E in CGTase catalysis, we have constructed several mutant... |
9828380 | Development of a biosensor for E. coli based on a flexural plate wave (FPW) transducer. | To fulfill the need for rapid, cost-effective and sensitive methods for the detection of bacteria in medical diagnostics, food technology, biotechnology and environmental monitoring, a development of a bacterial sensor was initiated. Our approach of a biosensor for E. coli is based on an acousto-gravimetric flexural pl... |
9827978 | Bacteraemia during the aplastic phase after allogeneic bone marrow transplantation is associated with early death from invasive fungal infection. | Episodes of bacteraemia during the aplastic phase were studied in 500 allogeneic bone marrow (BMT) recipients, regarding incidence, microbial aetiology, risk factors, mortality and causes of death. One hundred and sixty-four patients (33%) had at least one positive blood culture. Gram-positive cocci (alpha-streptococci... |
9818423 | On-line coupling of microdialysis sampling with liquid chromatography for the determination of peptide and non-peptide leukotrienes. | An automated on-line sampling method was developed using microdialysis as the simultaneous sampling and sample pre-treatment technique. The extraction fraction values of microdialysis probes sampling different eicosanoids were investigated. The impact of cyclodextrins in the perfusion liquid used for sampling hydrophob... |
9818355 | Growth, natural relationships, cellular fatty acids and metabolic adaptation of sulfate-reducing bacteria that utilize long-chain alkanes under anoxic conditions. | Natural relationships, improvement of anaerobic growth on hydrocarbons, and properties that may provide clues to an understanding of oxygen-independent alkane metabolism were studied with two mesophilic sulfate-reducing bacteria, strains Hxd3 and Pnd3. Strain Hxd3 had been formerly isolated from an oil tank; strain Pnd... |
9818270 | NMR structural studies of membrane proteins. | The three-dimensional structures of membrane proteins are essential for understanding their functions, interactions and architectures. Their requirement for lipids has hampered structure determination by conventional approaches. With optimized samples, it is possible to apply solution NMR methods to small membrane prot... |
9818257 | Cellulose, cellulases and cellulosomes. | The structural complexity and rigidity of cellulosic substrates have given rise to a phenomenal diversity of degradative enzymes--the cellulases. Cellulolytic microorganisms produce a wide variety of different catalytic and noncatalytic enzyme modules, which form the cellulases and act synergistically on their substrat... |
9818148 | Formation of an amino-acid-binding pocket through adaptive zippering-up of a large DNA hairpin loop. | <h4>Background</h4>In vitro selection has identified DNA aptamers that target cofactors, amino acids, peptides and proteins. Structure determination of such ligand-DNA aptamer complexes should elucidate the details of adaptive DNA structural transitions, binding-pocket architectures and ligand recognition. We have dete... |
9818090 | The role of proline in the prevention of aggregation during protein folding in vitro. | Proline effectively inhibits protein aggregation during the refolding of bovine carbonic anhydrase. Other osmolytes used such as glycine and ethylene glycol fail to exhibit the 'aggregation-blockade' role shown by proline. Results of viscosity and ANS fluorescence (1-anilino-8-naphthalene sulphonic acid) experiments su... |
9809070 | Formation of a novel four-helix bundle and molecular recognition sites by dimerization of a response regulator phosphotransferase. | A basis for understanding specificity of molecular recognition between phosphorelay proteins has been deduced from the 2.6 A structure of the Spo0B phosphotransferase of the phosphorelay regulating sporulation initiation. Spo0B consists of two domains: an N-terminal alpha-helical hairpin domain and a C-terminal alpha/b... |
9809750 | Multiple initiations in the c-myc replication origin independent of chromosomal location. | At supramolecular resolution, DNA synthesis begins at preferred replication origins in the chromosomes of metazoan cells. To characterize one of these origins in detail, the initiation of replication was examined in the HeLa c-myc origin. Polymerase chain reaction (PCR) amplification of size-fractionated nascent chromo... |
9799623 | Posttraining estrogen and memory modulation. | The present paper provides a review of recent research carried out in this laboratory investigating the effects of posttraining peripheral and intrahippocampal injection of estradiol on memory in rats, and estradiol-acetylcholine interactions in memory modulation. Ovariectomized rats received an eight-trial training se... |
9799368 | Phylogenetic analysis of plastid origins based on secA sequences. | We have generated secA sequence data from a number of photosynthetic prokaryotes and carried out a phylogenetic analysis using secA sequences from prokaryotes, green plants, and red and brown algae. We have studied the substitution patterns that give rise to the apparent phylogenetic structure. We show that the high AT... |
9795258 | A new tool for studying the molecular architecture of the fungal cell wall: one-step purification of recombinant trichoderma beta-(1-6)-glucanase expressed in Pichia pastoris. | The fungal cell wall is a supramolecular network of glycoproteins and polysaccharides. Its analysis is seriously hampered by the lack of easily available hydrolytic enzymes in a pure form. Here we describe a simple and efficient purification procedure of a recombinant beta-(1-6)-glucanase from Trichoderma harzianum exp... |
9796431 | Kinetic spectroscopy of erythrosin phosphorescence and delayed fluorescence in aqueous solution at room temperature. | The photophysics and polarization of the phosphorescence and delayed fluorescence of erythrosin in conditions compatible with the current biological applications of the dye (aqueous buffers at pH 7.4 at ambient temperatures) and in ethanol have been studied as a function of dye concentration (10(-7)-10(-5) M) and tempe... |
9796418 | Neutral carrier-type ion sensors based on sol-gel-derived membranes incorporating a bis(crown ether) derivative by covalent bonding. | Sol-gel-derived membranes incorporating crown ether neutral carriers by covalent bonding have been designed for durable, nontoxic neutral carrier-type ion sensors by sol-gel processing using tetraethoxysilane, diethoxydimethylsilane, and their corresponding alkoxysilylated neutral carriers. A tetraphenylborate anion wa... |
9794499 | Design and evaluation of an osmotic pump tablet (OPT) for prednisolone, a poorly water soluble drug, using (SBE)7m-beta-CD. | <h4>Purpose</h4>The purpose of this study was to develop a controlled-porosity osmotic pump tablet (OPT) for poorly water soluble drugs using a sulfobutyl ether-beta-cyclodextrin, (SBE)7m-beta-CD or Captisol, which acted as both a solubilizer and as an osmotic agent.<h4>Methods</h4>Prednisolone (PDL) was chosen as a mo... |
9788966 | The Ile164 beta2-adrenergic receptor polymorphism adversely affects the outcome of congestive heart failure. | The beta2-adrenergic receptor (beta2AR), an important modulator of cardiac inotropy and chronotropy, has significant genetic heterogeneity in the population. Because dysfunctional betaARs play a role in the pathogenesis of the failing ventricle, we tested the hypothesis that beta2AR polymorphisms alter the outcome of c... |
9789023 | Direct molecular level measurements of the electrostatic properties of a protein surface. | In this work, we used direct measurements with the surface force apparatus to determine the pH-dependent electrostatic charge density of a single binding face of streptavidin. Mean field calculations have been used with considerable success to model electrostatic potential fields near protein surfaces, but these models... |
9789022 | Inhibiting transthyretin conformational changes that lead to amyloid fibril formation. | Insoluble protein fibrils resulting from the self-assembly of a conformational intermediate are implicated as the causative agent in several severe human amyloid diseases, including Alzheimer's disease, familial amyloid polyneuropathy, and senile systemic amyloidosis. The latter two diseases are associated with transth... |
9789015 | Comparison of x-ray crystal structures of an acyl-enzyme intermediate of subtilisin Carlsberg formed in anhydrous acetonitrile and in water. | The x-ray crystal structures of trans-cinnamoyl-subtilisin, an acyl-enzyme covalent intermediate of the serine protease subtilisin Carlsberg, have been determined to 2.2-A resolution in anhydrous acetonitrile and in water. The cinnamoyl-subtilisin structures are virtually identical in the two solvents. In addition, the... |
9788999 | In vitro evolution of horse heart myoglobin to increase peroxidase activity. | Random mutagenesis and screening for enzymatic activity has been used to engineer horse heart myoglobin to enhance its intrinsic peroxidase activity. A chemically synthesized gene encoding horse heart myoglobin was subjected to successive cycles of PCR random mutagenesis. The mutated myoglobin gene was expressed in Esc... |
9790678 | Mechanism of synergism between antimicrobial peptides magainin 2 and PGLa. | The antimicrobial peptides magainin 2 and PGLa, discovered in the skin of the African clawed frog, Xenopus laevis, exhibit marked synergism [Westerhoff, H. V., Zasloff, M., Rosner, J. L., Hendler, R. W., de Waal, A., Vaz Gomes, A., Jongsma, A. P. M., Riethorst, A., and Juretic, D., Eur. J. Biochem. 228, 257-264 (1995)]... |
9790673 | Role of the isoprenyl tail of ubiquinone in reaction with respiratory enzymes: studies with bovine heart mitochondrial complex I and Escherichia coli bo-type ubiquinol oxidase. | The hydrophobic isoprene tail of ubiquinone-2 (Q2) exihibits binding specificity in redox reactions with bovine heart mitochondrial complex I (Ohshima, M., Miyoshi, H., Sakamoto, K., Takegami, K., Iwata, J., Kuwabara, K., Iwamura, H., and Yagi, T. (1998) Biochemistry 37, 6436-6445) and the Escherichia coli bo-type ubiq... |
9792100 | Tertiary structure-dependence of misfolding substitutions in loops of the maltose-binding protein. | We previously identified and characterized amino acid substitutions in a loop connecting helix I to strand B, the alphaI/betaB loop, of the N-domain that are critical for in vivo folding of the maltose-binding protein (MalE31). The tertiary context-dependence of this mutation in MalE folding was assessed by probing the... |
9784241 | Binding of the cysteine proteinases papain and cathepsin B-like to coated laminin: use of synthetic peptides from laminin and from the laminin binding region of the beta 1 integrin subunit to characterize the binding site. | Cysteine proteinases of the papain superfamily, i.e., papain and cathepsin B-like proteinase, were found to be able to bind to laminin-coated wells. When papain and cathepsin B-like proteinase were used, saturable binding curves were found. The characterization of the binding site was carried out using synthetic peptid... |
9786946 | The dynamin-related GTPase, Dnm1p, controls mitochondrial morphology in yeast. | The Saccharomyces cerevisiae Dnm1 protein is structurally related to dynamin, a GTPase required for membrane scission during endocytosis. Here we show that Dnm1p is essential for the maintenance of mitochondrial morphology. Disruption of the DNM1 gene causes the wild-type network of tubular mitochondrial membranes to c... |
9784498 | HSP101 functions as a specific translational regulatory protein whose activity is regulated by nutrient status. | The 5' leader (Omega) of tobacco mosaic viral RNA functions as a translational enhancer. Sequence analysis of a 102-kD protein, identified previously as a specific Omega RNA-binding protein, revealed homology to the HSP101/HSP104/ClpB family of heat shock proteins and its expression in yeast complemented a thermotolera... |
9788310 | Cyclodextrins as selectivity enhancers in capillary zone electrophoresis of proteins. | The selectivity in the capillary zone electrophoresis (CZE) of a variety of acidic and basic proteins including alpha-chymotrypsinogen A, cytochrome c, lysozyme, ribonuclease A, ovalbumin, and beta-lactoglobulins A and B, was altered by adding 6-monodeoxy-6-monoamino-beta-cyclodextrin or carboxymethylated beta-cyclodex... |
9781692 | Factors limiting display of foreign peptides on the major coat protein of filamentous bacteriophage capsids and a potential role for leader peptidase. | Many small peptides can be displayed on every copy of the major coat protein in recombinant filamentous bacteriophages but larger peptides can only be accommodated in hybrid virions mixed with wild-type protein subunits. A peptide insert of 12 residues capable of display at high copy number in a hybrid virion was found... |
9777251 | Characterization of the human gonadotropin-releasing hormone receptor heterologously produced using the baculovirus/insect cell and the Semliki Forest virus systems. | 1. Two eukaryotic viral systems, the baculovirus/insect cell and the Semliki Forest virus systems, were tested for heterologous expression of human gonadotropin-releasing hormone receptor (GnRHR) cDNA. 2. An unmodified as well as a c-myc epitope-tagged human GnRH receptor was produced in two insect cell lines (Spodopte... |
9774339 | Pathogenic poxviruses reveal viral strategies to exploit the ErbB signaling network. | Virulence of poxviruses, the causative agents of smallpox, depends on virus-encoded growth factors related to the mammalian epidermal growth factor (EGF). Here we report that the growth factors of Shope fibroma virus, Myxoma virus and vaccinia virus (SFGF, MGF and VGF) display unique patterns of specificity to ErbB rec... |
9772164 | Stabilization of radical intermediates by an active-site tyrosine residue in methylmalonyl-CoA mutase. | The adenosylcobalamin-dependent methylmalonyl-CoA mutase catalyzes the reversible rearrangement of methylmalonyl-CoA into succinyl-CoA by a free-radical mechanism. The recently solved X-ray crystal structure of methylmalonyl-CoA mutase from Propionibacterium shermanii has shown that tyrosine 89 is an active-site residu... |
9770482 | Low frequency vibrational modes in proteins: changes induced by point-mutations in the protein-cofactor matrix of bacterial reaction centers. | As a step toward understanding their functional role, the low frequency vibrational motions (<300 cm-1) that are coupled to optical excitation of the primary donor bacteriochlorophyll cofactors in the reaction center from Rhodobacter sphaeroides were investigated. The pattern of hydrogen-bonding interaction between the... |
9770479 | The structure and organization within the membrane of the helices composing the pore-forming domain of Bacillus thuringiensis delta-endotoxin are consistent with an "umbrella-like" structure of the pore. | The aim of this study was to elucidate the mechanism of membrane insertion and the structural organization of pores formed by Bacillus thuringiensis delta-endotoxin. We determined the relative affinities for membranes of peptides corresponding to the seven helices that compose the toxin pore-forming domain, their modes... |
9770452 | The role of the ClpA chaperone in proteolysis by ClpAP. | ClpA, a member of the Clp/Hsp100 family of ATPases, is a molecular chaperone and, in combination with a proteolytic component ClpP, participates in ATP-dependent proteolysis. We investigated the role of ClpA in protein degradation by ClpAP by dissociating the reaction into several discrete steps. In the assembly step, ... |
9770445 | Ionophores and receptors using cation-pi interactions: collarenes. | Cation-pi interactions are important forces in molecular recognition by biological receptors, enzyme catalysis, and crystal engineering. We have harnessed these interactions in designing molecular systems with circular arrangement of benzene units that are capable of acting as ionophores and models for biological recep... |
9770443 | A peptide that inhibits hydroxyapatite growth is in an extended conformation on the crystal surface. | Proteins play an important role in the biological mechanisms controlling hard tissue development, but the details of molecular recognition at inorganic crystal interfaces remain poorly characterized. We have applied a recently developed homonuclear dipolar recoupling solid-state NMR technique, dipolar recoupling with a... |
9773884 | Supramolecular receptor structures in the plasma membrane of lymphocytes revealed by flow cytometric energy transfer, scanning force- and transmission electron-microscopic analyses. | Receptors in the plasma membrane of blood cells in general and in that of lymphocytes in particular are supposed to move around in a random walk fashion relatively freely driven by thermal diffusion, as described by the Singer-Nicolson fluid mosaic membrane model. In this article we summarized data and techniques that ... |
9767629 | Structure-based design of cathepsin K inhibitors containing a benzyloxy-substituted benzoyl peptidomimetic. | Peptidomimetic cathepsin K inhibitors have been designed using binding models which were based on the X-ray crystal structure of an amino acid-based, active site-spanning inhibitor complexed with cathepsin K. These inhibitors, which contain a benzyloxybenzoyl group in place of a Cbz-leucine moiety, maintained good inhi... |
9765579 | The 20S proteasome of Streptomyces coelicolor. | 20S proteasomes were purified from Streptomyces coelicolor A3(2) and shown to be built from one alpha-type subunit (PrcA) and one beta-type subunit (PrcB). The enzyme displayed chymotrypsin-like activity on synthetic substrates and was sensitive to peptide aldehyde and peptide vinyl sulfone inhibitors and to the Strept... |
9767121 | Effect of beta-cyclodextrin dietary supplementation on biliary proteins and their resulting cholesterol nucleating activity in pigs. | We explored the possibility that the biliary protein fraction may support part of the variation in the nucleating activity previously measured in gallbladder biles of pigs. Eighteen gallbladder aspirates freshly obtained from three dietary groups (0, 5, or 10% beta-cyclodextrin) of six pigs were chromatographed to puri... |
9768788 | Fundamental properties of local anesthetics: half-maximal blocking concentrations for tonic block of Na+ and K+ channels in peripheral nerve. | <h4>Unlabelled</h4>Local anesthetics suppress excitability by interfering with ion channel function. Ensheathment of peripheral nerve fibers, however, impedes diffusion of drugs to the ion channels and may influence the evaluation of local anesthetic potencies. Investigating ion channels in excised membrane patches avo... |
9763531 | Cholesterol metabolism and efflux in human THP-1 macrophages. | This study has investigated in detail factors regulating accumulation, esterification, and mobilization of cholesterol in human THP-1 macrophages. Human THP-1 monocytes were differentiated into macrophages and then cholesterol enriched by exposure to acetylated LDL (AcLDL), together with [3H]free cholesterol (FC). Alth... |
9765310 | The pleckstrin homology domains of dynamin isoforms require oligomerization for high affinity phosphoinositide binding. | The dynamins are 100-kDa GTPases involved in the scission event required for formation of endocytotic vesicles. The two main described mammalian dynamins (dynamin-1 and dynamin-2) both contain a pleckstrin homology (PH) domain, which has been implicated in dynamin binding to (and activation by) acidic phospholipids, mo... |
9763437 | Fibronectin matrix regulates activation of RHO and CDC42 GTPases and cell cycle progression. | Adherent cells assemble fibronectin into a fibrillar matrix on their apical surface. The fibril formation is initiated by fibronectin binding to the integrins alpha5 beta1 and alphav beta3, and is completed by a process that includes fibronectin self-assembly. We found that a 76- amino acid fragment of fibronectin (III... |
9763424 | Small espin: a third actin-bundling protein and potential forked protein ortholog in brush border microvilli. | An approximately 30-kD isoform of the actin-binding/ bundling protein espin has been discovered in the brush borders of absorptive epithelial cells in rat intestine and kidney. Small espin is identical in sequence to the COOH terminus of the larger ( approximately 110-kD) espin isoform identified in the actin bundles o... |
9763441 | The role of topoisomerase II in meiotic chromosome condensation and segregation in Schizosaccharomyces pombe. | Topoisomerase II is able to break and rejoin double-strand DNA. It controls the topological state and forms and resolves knots and catenanes. Not much is known about the relation between the chromosome segregation and condensation defects as found in yeast top2 mutants and the role of topoisomerase II in meiosis. We st... |
9761744 | Effects of cholesterol depletion by cyclodextrin on the sphingolipid microdomains of the plasma membrane. | Sphingolipid microdomains are thought to result from the organization of plasma membrane sphingolipids and cholesterol into a liquid ordered phase, wherein the glycosylphosphatidylinositol (GPI)-anchored proteins are enriched. These domains, resistant to extraction by cold Triton X-100, can be isolated as buoyant membr... |
9761736 | Sulphated glycosaminoglycans prevent the neurotoxicity of a human prion protein fragment. | Although a number of features distinguish the disease isoform of the prion protein (PrPSc) from its normal cellular counterpart (PrPC) in the transmissible spongiform encephalopathies (TSEs), the neuropathogenesis of these diseases remains an enigma. The amyloid fibrils formed by fragments of human PrP have, however, b... |
9761725 | The rate of sphingomyelin synthesis de novo is influenced by the level of cholesterol in cultured human skin fibroblasts. | Plasma membrane sphingomyelin (SM) is known to affect the cellular distribution of cholesterol. The aim of this work was to examine how SM homoeostasis in human skin fibroblasts is affected by alterations in the level of cholesterol in the cell. The cellular cholesterol level was decreased by exposing cells to 2-hydrox... |
9758813 | Stereo- and regioselective hydroxylation of alpha-ionone by Streptomyces strains. | A total of 215 Streptomyces strains were screened for their capacity to regio- and stereoselectively hydroxylate beta- and/or alpha-ionone to the respective 3-hydroxy derivatives. With beta-ionone as the substrate, 15 strains showed little conversion to 4-hydroxy- and none showed conversion to the 3-hydroxy product as ... |
9755201 | Modulation of MSL1 abundance in female Drosophila contributes to the sex specificity of dosage compensation. | Dosage compensation in Drosophila is the mechanism by which X-linked gene expression is made equal in males and females. Proper regulation of this process is critical to the survival of both sexes. Males must turn the male-specific lethal (msl)-mediated pathway of dosage compensation on and females must keep it off. Th... |
9755160 | alphaKAP is an anchoring protein for a novel CaM kinase II isoform in skeletal muscle. | Ca2+/calmodulin-dependent protein kinase II (CaM kinase II) is present in a membrane-bound form that phosphorylates synapsin I on neuronal synaptic vesicles and the ryanodine receptor at skeletal muscle sarcoplasmic reticulum (SR), but it is unclear how this soluble enzyme is targeted to membranes. We demonstrate that ... |
9753742 | Identification and hydropathic characterization of structural features affecting sequence specificity for doxorubicin intercalation into DNA double-stranded polynucleotides. | The computer molecular modeling program HINT (Hydropathic INTeractions), an empirical hydropathic force field function that includes hydrogen bonding, coulombic and hydrophobic terms, was used to study sequence-selective doxorubicin binding/intercalation in the 64 unique CAxy, CGxy, TAxy, TGxy base pair quartet combina... |
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