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2016704 | Conformationally constrained renin inhibitory peptides: cyclic (3-1)-1-(carboxymethyl)-L-prolyl-L-phenylalanyl-L-histidinamide as a conformational restriction at the P2-P4 tripeptide portion of the angiotensinogen template. | Interest in conformationally constrained peptides as potential inhibitors of renin led us to examine an N-terminal cycle of linear renin inhibitory peptides. A cyclic structure was prepared by joining the N-terminal proline at the P4 site to the imidazole ring of histidine at the P2 site via a carboxymethylene fragment... |
2015914 | Molecular recognition in the binding of vitamin B12 by the cobalamin-specific Intrinsic Factor. | Equilibrium constants (given as log K/M-1) have been determined at pH 7.4 and 4 degrees C for binding by porcine Intrinsic Factor (B12-binding protein from the gut, specific for the 'cobalamin' series of Co corrinoids) of vitamin B12 or cyanocobalamin (10.5), cyanocobinamide, alpha-ribazole and alpha-ribazole-phosphate... |
2015822 | Studies on the molecular recognition of synthetic methyl beta-lactoside analogs by ricin, a cytotoxic plant lectin. | The binding of methyl beta-lactoside and of all possible monodeoxy derivatives of methyl beta-lactoside to the galactose-specific highly cytotoxin lectin ricin, has been investigated. The distribution of low-energy conformers of the disaccharide structures has been first determined using molecular-mechanics calculation... |
1849737 | Ligand interaction energies and molecular recognition by chloramphenicol acetyltransferase. | The apparent binding energy for the interaction of the 3-hydroxyl group of chloramphenicol (CM) with the proposed general base (His-195) in chloramphenicol acetyltransferase (CAT) was determined by comparison of the dissociation constants of CM and 3-deoxyCM with CAT. The delta Gapp for this hydrogen bond to the N-3 of... |
2014229 | Identification of a determinant within the human immunodeficiency virus 1 surface envelope glycoprotein critical for productive infection of primary monocytes. | Profound differences exist in the replicative capacities of various human immunodeficiency virus 1 isolates in primary human monocytes. To investigate the molecular basis for these differences, recombinant full-length clones were constructed by reciprocal DNA fragment exchange between a molecular clone derived from a m... |
1901454 | Inhibition of mineralization of glutaraldehyde-pretreated bovine pericardium by AlCl3. Mechanisms and comparisons with FeCl3, LaCl3, and Ga(NO3)3 in rat subdermal model studies. | In the present study, the authors investigated the mechanism by which Al3+ preincubations inhibited the pathologic calcification of glutaraldehyde-pretreated bovine pericardium (GPBP) implanted subdermally in rats. The concentration dependency of the Al3+ anticalcification effect was compared with that of other trivale... |
1707238 | A novel chain of basement membrane-associated collagen as revealed by biochemical and immunohistochemical characterizations of the epitope recognized by a monoclonal antibody against human placenta basement membrane collagen. | Biochemical and immunohistochemical characterizations of the epitope recognized by a monoclonal antibody, JK-132, originally produced against human type IV collagen showed that it was distinct from the previously reported monoclonal antibody, JK-199 (Kino et al, J Biochem 1988, 103:829-835). The bound fraction of a cru... |
2011595 | Prediction of the thermodynamics of protein unfolding: the helix-coil transition of poly(L-alanine). | The method given earlier for predicting the thermodynamics of protein unfolding from the x-ray structure of a protein is applied here to the poly(L-alanine) helix. First, the fitting parameters derived earlier from a data base of 10 proteins were used to predict the unfolding thermodynamics of 4 other proteins. The agr... |
2011577 | Anti-Tac-H, a humanized antibody to the interleukin 2 receptor, prolongs primate cardiac allograft survival. | High-affinity interleukin 2 receptors (IL-2Rs) are expressed by T cells activated in response to foreign histocompatibility antigens but not by normal resting T cells. To exploit this difference in IL-2R expression, anti-Tac-M, a murine monoclonal antibody specific for the IL-2R alpha chain, was used to inhibit organ a... |
2010469 | The NC1 domain of type IV collagen promotes axonal growth in sympathetic neurons through interaction with the alpha 1 beta 1 integrin. | We have examined the effects of collagen IV on the morphological development of embryonic rat sympathetic neurons in vitro. In short-term (less than or equal to 24 h) culture, collagen IV accelerated process outgrowth, causing increases in the number of neurites and total neuritic length. Analysis of proteolytic fragme... |
2010058 | Mutations in collagen genes: causes of rare and some common diseases in humans. | More than 70 mutations in the two structural genes for type I procollagen (COL1A1 and COL1A2) have been found in probands with osteogenesis imperfecta, a heritable disease of children characterized by fragility of bone and other tissues rich in type I collagen. The mutations include deletions, insertions, RNA splicing ... |
2009856 | A nucleation--elongation mechanism for the self-assembly of side polar sheets of smooth muscle myosin. | Self-assembled filaments of smooth muscle myosin were observed by low dose electron microscopy to be flat side-polar sheets, in which the component molecules appeared straight and close-packed. Fraying experiments released small oligomers, in which molecules were staggered in parallel by about +/- 14 nm relative to two... |
1901052 | Low-temperature induction of Myxococcus xanthus developmental gene expression in wild-type and csgA suppressor cells. | The csgA gene encodes an extracellular protein that plays an essential role in the regulation of fruiting-body formation and sporulation of Myxococcus xanthus. The csgA suppressor allele soc-500 (formerly referred to as csp-500) was selected based on its ability to restore sporulation to csgA cells under developmental ... |
1826042 | Recognition of U1 and U2 small nuclear RNAs can be altered by a 5-amino-acid segment in the U2 small nuclear ribonucleoprotein particle (snRNP) B" protein and through interactions with U2 snRNP-A' protein. | We have investigated the sequence elements influencing RNA recognition in two closely related small nuclear ribonucleoprotein particle (snRNP) proteins, U1 snRNP-A and U2 snRNP-B". A 5-amino-acid segment in the RNA-binding domain of the U2 snRNP-B" protein was found to confer U2 RNA recognition when substituted into th... |
2005880 | Identification of base and backbone contacts used for DNA sequence recognition and high-affinity binding by LAC9, a transcription activator containing a C6 zinc finger. | The LAC9 protein of Kluyveromyces lactis is a transcriptional regulator of genes in the lactose-galactose regulon. To regulate transcription, LAC9 must bind to 17-bp upstream activator sequences (UASs) located in front of each target gene. LAC9 is homologous to the GAL4 protein of Saccharomyces cerevisiae, and the two ... |
2005200 | Inhibition of peripheral aromatization in the male cynomolgus monkey by a novel nonsteroidal aromatase inhibitor (R 76713). | R 76713 (6-[(4-chlorophenyl)(1-H-1,2,4-trizol-1-yl)methyl]1-H benzotriazole) is a highly potent and selective inhibitor of the aromatase enzyme both in vitro and in vivo. The ability of R 76713 to inhibit peripheral aromatization of androstenedione (A) to estrone (E1) in vivo was studied in male cynomolgus monkeys (Mac... |
1848318 | Coinfection with recombinant vaccinia viruses expressing poliovirus P1 and P3 proteins results in polyprotein processing and formation of empty capsid structures. | The assembly process of poliovirus occurs via an ordered proteolytic processing of the capsid precursor protein, P1, by the virus-encoded proteinase 3CD. To further delineate this process, we have isolated a recombinant vaccinia virus which expresses, upon infection, the poliovirus P1 capsid precursor polyprotein with ... |
1848307 | Derivatives of Moloney murine sarcoma virus capable of being transcribed in embryonal carcinoma stem cells have gained a functional Sp1 binding site. | The long terminal repeat (LTR) sequences of Moloney murine leukemia virus and its closely related derivative Moloney murine sarcoma virus (Mo-MSV) are incapable of directing transcription in embryonal carcinoma (EC) stem cells. The myeloproliferative sarcoma virus, a derivative of Mo-MSV, has several point mutations in... |
1804277 | Mass analysis of bacteriophage T4 proheads and mature heads by scanning transmission electron microscopy and hydrodynamic measurements. | Quantitative mass analysis of bacteriophage T4 proheads by scanning transmission electron microscopy (STEM) revealed a mass of 79.5 +/- 0.6 MDa, while hydrodynamic measurements yielded a prohead mass of about 80 MDa. This is 25% less than the prohead mass deduced from its polypeptide composition, and this finding impli... |
24242175 | Continuous-flow fast atom bombardment mass spectrometry of oligonucleotides. | Although frit-fast atom bombardment (frit-FAB) and continuous-flow FAB mass spectrometry have become standard methods for the analysis of peptides and peptide mixtures, these techniques have not been applied previously to the analysis of oligonucleotides. Mobilephase composition, flow rate, and sample size were optimiz... |
19283124 | Influence of Lectins on Constricting Ring Formation by Arthrobotrys dactyloides. | Incubation of Arthrobotrys dactyloides conidia in the presence of Radopholus citrophilus in lectin solutions with their corresponding sugars did not alter the stimulation of trap formation in solutions containing lectins alone. The lack of inhibition of lectin-stimulated trap formation by sugars or by lectin denaturati... |
18600678 | Enzymatic production of cyclodextrins from unliquefied corn starch in an attrition bioreactor. | A novel enzymatic process for the production of cyclodextrins from unliquefied starch was developed. Cyclodextrins were produced in an attrition bioreactor in which simultaneous hydrolysis of starch and synthesis of cyclodextrins by cyclodextrin glycosyltransferase (CGTase) occur. The CGTase was obtained from isolated ... |
1912068 | [Regulation of supermolecular organization and catalytic activity of the lysosomal complex GM1-galactosidase and neuraminidase in vitro]. | The regulation of the catalytic activity and supramolecular organization of human kidney Gm1-galactosidase and neuraminidase was investigated in the reversed micellar systems of Aerosol OT in octane. It was found that in the reversed micellar systems the Gm1-galactosidase can exist in the monomeric, tetrameric or octam... |
1885686 | Determination of sorbic acid in margarine and butter by high-performance liquid chromatography with fluorescence detection. | A procedure is reported for the separation and determination of sorbic acid, as a derivative of 4-bromoethyl-6,7-dimethoxycoumarin, by reversed-phase high-performance liquid chromatography with fluorescence detection using enanthic acid as an internal standard. Sorbic acid, separated from samples of commercial margarin... |
1885684 | High-performance liquid chromatographic separation of racemic and diastereomeric mixtures of 2,4-pentadienoate-iron tricarbonyl derivatives. | beta-Cyclodextrin chiral stationary phase facilitates the chiral separation of the (+/-)-methyl-5-formyl-2,4-pentadienoate-iron tricarbonyl (1) racemic mixture. The separation of oxazolidine derivatives 2 and 3 diastereomers were achieved with a C18 column but the compounds underwent in-column hydrolysis to give (-)- a... |
1882711 | The effect of detergents on firefly luciferase reactions. | The reaction rate of ATP-limited firefly luciferase-catalysed reactions, is affected by the presence of detergents. Anionic detergents inhibit luciferase activity without causing significant enzyme inactivation during the reaction. Cationic detergents increase reaction rate several-fold with a sharply defined optimum c... |
2071951 | [Simple and efficient method for clinical isolation of Bordetella pertussis]. | Commercially available Amies transport medium with charcoal and three isolation media were tested to assess their efficiency in the clinical isolation of B. pertussis. First, the isolation rates of B. pertussis were compared between direct inoculation of nasopharyngeal specimens and inoculation after stored in Amies tr... |
1829899 | Structure of a photoresponsive crown ether, 21-(4'-methoxyphenylazo)-1,4,7,14,23-pentaoxa[7.2.2] orthometaorthobenzenophane. | 3,10,13,16,23-Pentaoxatetracyclo-[23.3.1.0.(4,9)0(17,22)]nonaco sa-1(29), 4,6,8,17,19,21,25,27-nonaene-29-azo-(4'-methoxybenzene), C31H30N2O6, Mr = 526, monoclinic, P2(1)/n, a = 14.564 (3), b = 19.177 (2), c = 10.025 (2) A, beta = 100.42 (1) degrees, V = 2754 (1) A3, Z = 4, Dx = 1.269 g cm-3, Mo K alpha, lambda = 0.710... |
2065378 | [Immunological injury from serum sickness on aortic connective tissue components]. | Changes of aortic proteoglycan, collagen and elastic fibers following immunological injury were studied quantitatively and qualitatively under electron microscope after ruthenium red labelling. The results showed that repeated intravenous injections of bovine serum albumin in rabbits activated the synthesis of collagen... |
2054900 | Phospholipid phase transitions: kinetics and structural mechanisms. | A brief review is given on the principles and methods used to investigate structural phase transitions in phospholipid supramolecular structures. The conceptual differences of approaches close to and far from equilibrium are addressed, and the consequences in terms of the limits of interpretation for different types of... |
2052529 | The effects of cyclodextrins on the disposition of intravenously injected drugs in the rat. | Naproxen and flurbiprofen form complexes with hydroxypropyl-beta-cyclodextrin; with stability constants of 2207 and 12515 M-1, respectively. However, only small fractions of the drug remain complexed when the drug-cyclodextrin complex is added to plasma in vitro. This result can be explained by albumin effectively comp... |
2045963 | Fertilization-induced changes in the vitelline envelope of echinoderm and amphibian eggs: self-assembly of an extracellular matrix. | The surface of the unfertilized sea urchin egg is covered by the vitelline layer (VL), a fibrous extracellular matrix that contains receptors for sperm. At fertilization, cortical granule exocytosis releases enzymes and structural proteins that cause the VL to elevate and become remodelled into the mechanically and che... |
2039236 | In vitro measurement of the adherence of Staphylococcus epidermidis to plastic by using cellular urease as a marker. | A rapid and sensitive in vitro assay was developed to quantitatively assess the adherence of Staphylococcus epidermidis to a hydrophobic plastic surface. The assay is based upon the detection of cell-associated urease activity as a marker of bacteria remaining adherent to the polystyrene microwells of flat-bottomed, 96... |
2030672 | Cellulose biosynthesis and function in bacteria. | The current model of cellulose biogenesis in plants, as well as bacteria, holds that the membranous cellulose synthase complex polymerizes glucose moieties from UDP-Glc into beta-1,4-glucan chains which give rise to rigid crystalline fibrils upon extrusion at the outer surface of the cell. The distinct arrangement and ... |
2015856 | Accessibility of crystallins to HCI gas. | Different crystallins (alpha, beta H, beta L and LMW) were isolated from bovine lenses. Lyophilized samples of single components (homoaggregates) and those of mixtures (heteroaggregates) were exposed to HCI vapor in a high vacuum vapor sorption apparatus. Lyophilized 5-microns sections of bovine lens were similarly exp... |
2012613 | Characterization of inositol 1,4,5-trisphosphate- and inositol 1,3,4,5-tetrakisphosphate-binding sites in rat cerebellum. | 1. The properties of specific Ins(1,4,5)P3- and Ins(1,3,4,5)P4-binding sites have been compared in a crude 'P2' cerebellar membrane fraction. 2. A homogeneous population of [3H]Ins(1,4,5)P3-binding sites was present (KD 23.1 +/- 3.6 nM) at high density (Bmax. 11.9 +/- 1.8 pmol/mg of protein); whereas data obtained for ... |
2012610 | Isolation of two N-monosubstituted protoporphyrins, bearing either the whole drug or a methyl group on the pyrrole nitrogen atom, from liver of mice given griseofulvin. | 1. A hepatic green pigment with inhibitory properties towards the enzyme ferrochelatase has been isolated from the liver of mice treated with griseofulvin and identified as N-methylprotoporphyrin. 2. All four structural isomers of N-methylprotoporphyrin have been demonstrated to be present, NA, where ring A of protopor... |
2006184 | A self-assembling protein kinase C inhibitor. | Previous studies have described a dicationic anticarcinoma agent that can chemically assemble in situ from monocationic phosphonium salts. The chemical combination of these monocationic precursors in the micromolar concentration range, occurring after their uptake by cells, was probably responsible for their synergisti... |
2002500 | Supramolecular organization of double-stranded DNA molecules in the columnar hexagonal liquid crystalline phase. An electron microscopic analysis using freeze-fracture methods. | I present an electron microscopical analysis of the columnar hexagonal liquid crystalline phase of DNA. Freeze-fracture methods reveal that this phase is a lamellar structure, each layer (30 to 40 A thick) composed of DNA molecules aligned in parallel. Numerous defects can be seen in the structure, and their nature is ... |
2002453 | A comparative NMR study between the macrolide antibiotic roxithromycin and erythromycin A with different biological properties. | 1H nuclear Overhauser enhancement studies and 1H NMR 3J analysis establish the similarity between the major solution-state conformation of roxithromycin (1) and the erythromycin (2). A major difference between the structure of antibiotics 1 and 2 is the replacement of the 9-keto group in 2 by a 9-[O-(2,5-dioxahexyl)oxi... |
1900510 | Myxococcus xanthus protein C is a major spore surface protein. | Fruiting body formation in Myxococcus xanthus involves the aggregation of cells to form mounds and the differentiation of rod-shaped cells into spherical myxospores. The surface of the myxospore is composed of several sodium dodecyl sulfate (SDS)-soluble proteins, the best characterized of which is protein S (Mr, 19,00... |
1705884 | Amino acid substitutions within the matrix protein of type D retroviruses affect assembly, transport and membrane association of a capsid. | The functional roles of the matrix (MA) protein in the assembly and maturation of retroviruses was investigated with a series of MA mutants of Mason-Pfizer monkey virus (M-PMV), an immunosuppressive type D retrovirus. The mutants we describe here were generated by the introduction of random point mutations within the M... |
2001367 | FTIRS in H2O demonstrates that collagen monomers undergo a conformational transition prior to thermal self-assembly in vitro. | The assembly of type I collagen molecules into native fibrils can be accomplished in vitro in solutions at physiological ionic strength and pH by raising the temperature above 30 degrees C. The thermal self-assembly reaction exhibits a distinct lag phase. This lag phase has been proposed to be evidence for a conformati... |
2000401 | The pharmacophore of debromoaplysiatoxin responsible for protein kinase C activation. | Protein kinase C is physiologically activated by 1,2-diacyl-sn-glycerol in the S configuration. The enzyme is also powerfully activated by structurally diverse tumor promotors. A model has been developed that demonstrates how the various tumor promotors and diacylglycerols can all be accommodated by the same binding si... |
1825658 | Spontaneous assembly of pore complex-containing membranes ("annulate lamellae") in Xenopus egg extract in the absence of chromatin. | Extract prepared from activated Xenopus eggs is capable of reconstituting nuclei from added DNA or chromatin. We have incubated such extract in the absence of DNA and found that numerous flattened membrane cisternae containing densely spaced pore complexes (annulate lamellae) formed de novo. By electron and immunofluor... |
1999454 | The properdin-like type I repeats of human thrombospondin contain a cell attachment site. | Thrombospondin (TS) is a modular adhesive glycoprotein that contains three domains previously implicated in the attachment of cells to TS. These include the amino-terminal heparin-binding domain, the carboxy terminal cell or platelet-binding domain, and an RGDA sequence of TS. We have characterized a mAb against human ... |
1705558 | Structure of the chicken neuron-glia cell adhesion molecule, Ng-CAM: origin of the polypeptides and relation to the Ig superfamily. | The neuron-glia cell adhesion molecule (Ng-CAM) mediates both neuron-neuron and neuron-glia adhesion; it is detected on SDS-PAGE as a predominant 135-kD glycoprotein, with minor components of 80, 190, and 210 kD. We have isolated cDNA clones encoding the entire sequence of chicken Ng-CAM. The predicted extracellular re... |
1899963 | Changes in plasma levels of tissue-plasminogen activator/inhibitor complex and active plasminogen activator inhibitor in patients with disseminated intravascular coagulation. | Plasma levels of tissue-plasminogen activator.plasminogen activator inhibitor (t-PA.PAI) complex and active PAI were assayed in 58 cases of disseminated intravascular coagulation (DIC). A significant elevation of both parameters was observed in most cases of DIC, especially in patients with non-Hodgkin lymphoma, sepsis... |
1847482 | Mutations in a herpes simplex virus type 1 origin that inhibit interaction with origin-binding protein also inhibit DNA replication. | The herpes simplex virus type 1 genome contains three origins of replication: OriL and a diploid OriS. The origin-binding protein, the product of the UL9 gene, interacts with two sites within OriS, box I and box II. A third site, box III, which is homologous to boxes I and II, may also be a binding site for the origin-... |
1995952 | Dextran sulfate blocks antibody binding to the principal neutralizing domain of human immunodeficiency virus type 1 without interfering with gp120-CD4 interactions. | The mechanism of the antiviral activity of sulfated polysaccharides on human immunodeficiency virus type 1 (HIV-1) was investigated by determining the effect of dextran sulfate on the binding of CD4 and several anti-gp120 monoclonal antibodies to both recombinant and cell surface gp120. Dextran sulfate did not interfer... |
1847456 | Sendai virus protein-protein interactions studied by a protein-blotting protein-overlay technique: mapping of domains on NP protein required for binding to P protein. | Proteins from Sendai virus particles and from infected cells were analyzed in a protein-blotting protein-overlay assay for their interaction with in vitro-synthesized, [35S]methionine-labeled viral proteins NP, P, and M. After separation by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, transfer onto polyvi... |
1825340 | The amino-terminal portion of CD1 of the adenovirus E1A proteins is required to induce susceptibility to tumor necrosis factor cytolysis in adenovirus-infected mouse cells. | Previous work by our laboratory and others has shown that mouse cells normally resistant to tumor necrosis factor can be made sensitive to the cytokine by the expression of adenovirus E1A. The E1A gene can be introduced by either infection or transfection, and either of the two major E1A proteins, 289R or 243R, can ind... |
1847446 | Characterization of the DNA-binding properties of the polyomavirus capsid protein VP1. | The major capsid protein of polyomavirus, VP1, has been expression cloned in Escherichia coli, and the recombinant VP1 protein has been purified to near homogeneity (A. D. Leavitt, T. M. Roberts, and R. L. Garcea, J. Biol. Chem. 260:12803-12809, 1985). With this recombinant protein, a nitrocellulose filter transfer ass... |
11607167 | The second amino acid of alfalfa mosaic virus coat protein is critical for coat protein-mediated protection. | Transgenic plants expressing the coat protein (CP) of alfalfa mosaic virus (AIMV) are resistant to infection by AIMV. A mutation was introduced into the second amino acid of the cDNA for the CP of AIMV. Three different transgenic tobacco lines expressing the mutant CP and two different transgenic tobacco lines expressi... |
1810350 | A strategy for efficient characterization of macromolecular heteroassociations via measurement of sedimentation equilibrium. | A method is proposed for the selection of experimental conditions for sedimentation equilibrium experiments that will provide maximal information about the values of equilibrium association constants within a given scheme for heteroassociation of two solute components. A discriminator function is proposed that indicate... |
1687353 | Production and characterization of antibodies to mouse scrapie-amyloid protein elicited by non-carrier linked synthetic peptide immunogens. | Two polyclonal antibodies were raised by immunizing rabbits with two non carrier-linked synthetic peptides whose amino acid sequences corresponded to codons 89-107 (peptide P1) and 219-233 (peptide P2) of the translated cDNA sequence of murine PrP protein. These free peptides, whose structural characteristics in soluti... |
1810349 | Immunological mapping of fine molecular surface structures of citrate synthase enzymes from different cell types. | Citrate synthase (EC 4.1.3.7), which is present in all living organisms as a key enzyme in aerobic energy metabolism, is one of the most highly phylogenetically conserved enzymes known in terms of its primary and active site structure. However, in terms of other parameters such as in vitro stability, tolerance to chang... |
1810348 | Cytokine conformations: predictive studies. | The amino acid sequences of human and murine haemopoietins have been analysed using algorithms predictive for secondary structure. The results for 19 of these proteins (human and murine interleukins 2, 3, 4, 5, 6, 7 and granulocyte, macrophage and granulocyte macrophage-colony stimulating factors as well as human eryth... |
1810347 | 'Hot spot' amino acid distribution in Ha-ras oncogene product p21: relationship to guanine binding site. | Although the rules which describe the atomic basis of structure-function relationships of proteins have yet to be deciphered, they are nevertheless coded within the framework of the amino acid and nucleotide sequence. The objectives of the present investigations were to document a composite, new approach for the evalua... |
1667264 | Proposed loci of interaction between bombesin and its receptor. | The non-coding strand of the bombesin receptor gene, when 'translated' 5' to 3', contains an interrupted sequence of the 10 amino acids of bombesin. This finding forms the basis for proposing the points of contact between bombesin and its receptor as well as a partial conformation of the binding region of the receptor. |
1810346 | A 500 MHz proton NMR study of stacking interactions: binding of tripeptide Lys-Tyr-Lys to tetradeoxynucleotide d-GpCpGpC. | The complete sequential assignment and conformation of d-GpCpGpC in D2O has been determined from 1D NMR spectra at 285-320 K and room temperature 2D-COSY and NOESY spectra. The tetradeoxynucleotide exists primarily as a right handed double helix at 285 K, having Tm as 314 K. On binding to a tripeptide Lys-Tyr-Lys in a ... |
1664260 | Molecular recognition between oligopeptides and nucleic acids: DNA binding selectivity of a series of 1,2,4-triazole-containing lexitropsins. | The synthesis of a series of 1,2,4-triazole-containing oligopeptide lexitropsins related to the natural antitumor antibiotic distamycin is described. The binding properties of these new agents to both native DNAs and synthetic polydeoxyribonucleotides were determined by UV absorption and circular dichroism studies. The... |
24242908 | Continuous lifetime distributions of β-cyclodextrin-anilinonaphthalene sulfonic acid inclusion complexes. | Fluorescence lifetimes are reported for a series of anilinonaphthalene sulfonate (ANS) probe molecules complexed with β-cyclodextrin (β-CD). The fluorescence decay kinetics are recovered by multifrequency phase and modulation measurements in concert with a global analysis scheme. In all cases studied, a continuous Lore... |
17014771 | Calculation of the optimal surface area for amphiphile molecules using the hard core method. | In this work, we have calculated the optimal surface area per amphiphile molecule using a two-dimensional gas of electric dipoles interacting with hard The optimal surface area can be evaluated according to a formula (in the two-body approximation) or as a root of an equation (in the three-body approximation). If the e... |
1878886 | Vibrational Raman optical activity of carbohydrates. | Vibrational Raman optical activity (R.o.a.) spectra of a range of carbohydrates in aqueous solution, measured in back-scattering between 700 and 1500 cm-1, are presented. Features were revealed that appear to be characteristic of details of the stereochemistry. Effects associated with the glycosidic linkage in di- and ... |
1905884 | Comparative performance of 14-crown-4 derivatives as lithium-selective electrodes. | A series of neutral ionophore-based lithium-selective liquid-membrane electrodes have been prepared and the electrode performance compared with similar electrodes based on the lithium ionophores ETH 1810-ortho-nitrophenyl octyl ether (oNPOE) and ETH 2137-bis(1-butylpentyl) adipate (BBPA). By using a diamide substituted... |
1711399 | Promotion of neuronal survival in vitro by thermal proteins and poly(dicarboxylic)amino acids. | Evaluating molecules for their ability to promote survival and growth of neurons, we tested thermal proteins on cultures of dissociated fetal rat forebrain neurons. (Thermal proteins are polyamino acids formed when mixtures of amino acids with minimal proportions of glutamic or aspartic acid are heated.) Thermal protei... |
2051892 | Triacylglycerol synthesis in the oleaginous yeast Candida curvata D. | Low rates of triacylglycerol (TAG) biosynthesis were observed in cell-free extracts of Candida curvata, but rates were increased up to 10-fold by adding either alpha- or beta-cyclodextrins. Spheroplasts, whole or gently disrupted, had higher rates of incorporation of both [U-14C]glycerol 3-phosphate or [1-14C]oleate in... |
2051328 | Physical properties of the complexes formed between heptakis(2,6-di-O-methyl)-beta-cyclodextrin, beta-cyclodextrin, and chlorambucil. | The solid complex of chlorambucil (CHL) and heptakis-(2,6-di-O-methyl)-beta-cyclodextrin (DIMEB) has been isolated from ethanol and analyzed by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), and powder X-ray diffractometry. The carbonyl stretching band of the complex, observed ... |
2051319 | Interaction of prostaglandin E1 with alpha-cyclodextrin in aqueous systems: stability of the inclusion complex. | Prostavasin, an inclusion complex of prostaglandin E1 (PGE1) with alpha-cyclodextrin (alpha-CD), is used in the therapy of thrombosis. Nuclear magnetic resonance measurements have been made to study the interaction of PGE1 with alpha-CD. The observed interaction (chemical shift) and the derived dissociation constant pr... |
2038032 | Cryosputtering--a combined freeze-drying and sputtering method for high-resolution electron microscopy. | Preparing cellular structures for visualization by high-resolution scanning electron microscopy (SEM) is a multi-step process which includes fixation, dehydration, drying and metal coating. Drying and metal coating are limiting for high-resolution work. Commonly, the dried samples are exposed to the air before they are... |
1903467 | [Hemopurification in the management of ARDS complicating multiple organ failure]. | In the field of critical care medicine, it has been claimed that ARDS often develops as a part of multiple organ failure (MOF). Since multi-modality therapy is necessary in the management of MOF, it is also mandatory even in the management of ARDS. Among the various therapeutic approaches for patients with MOF, hemopur... |
1850970 | Novel quinolone resistance mutations of the Escherichia coli DNA gyrase A protein: enzymatic analysis of the mutant proteins. | Using the techniques of gap misrepair mutagenesis and site-directed mutagenesis, we have generated two novel quinolone resistance mutations of the Escherichia coli DNA gyrase A protein. DNA sequencing showed these mutations to be Ser-83----Ala and Gln-106----Arg. The mutant proteins were overproduced and purified, and ... |
1708788 | Immunocytochemical localization and development of multiple kinds of neuropeptides and neuroendocrine proteins in the chick ultimobranchial gland. | The ultimobranchial gland is an endocrine organ consisting of C cell groups. In chickens, the glands are richly supplied by nerve fibers immunoreactive for neurofilaments. It was found by immunocytochemical staining that C cells of chick ultimobranchial glands showed immunoreactivities for multiple kinds of neuropeptid... |
1901990 | Nucleotides in precursor tRNAs that are required intact for catalysis by RNase P RNAs. | Precursor tRNAAsp molecules, containing a 26-base 5' leader, were treated with diethylpyrocarbonate, 50% hydrazine or anhydrous hydrazine/3M NaCl and then subjected to processing by RNase P RNAs from Escherichia coli or Bacillus subtilis. Fully processed tRNAs and material not successfully cleaved by the catalytic RNAs... |
2017364 | Xenopus laevis Oct-1 does not bind to certain histone H2B gene promoter octamer motifs for which a novel octamer-binding factor has high affinity. | Oct-1 and a second, previously unidentified octamer-binding protein (Oct-R) have been identified in extracts of Xenopus laevis oocytes and embryos. Oct-1 does not bind to the octamer motif associated with certain Xenopus laevis histone H2B gene promoters, whereas Oct-R binds well to this motif, but only in the sequence... |
1826504 | Column-friendly reversed-phase high-performance liquid chromatography of peptides and proteins using formic acid with sodium chloride and dynamic column coating with crown ethers. | Reversed-phase high-performance liquid chromatography of proteins, traditionally carried out with strong acids like trifluoroacetic acid or phosphoric acid, which can damage reversed-phase columns, can be performed with excellent results using the far milder formic acid in the presence of salt. For certain separations,... |
1848735 | Brain tumors. | Recent advances in experimental tumor biology are being applied to critical clinical problems of primary brain tumors. The expression of peripheral benzodiazepine receptors, which are sparse in normal brain, is increased as much as 20-fold in brain tumors. Experimental studies show promise in using labeled ligands to t... |
1826034 | Structure of cyclodextrin glycosyltransferase refined at 2.0 A resolution. | The previously reported structural model of cyclodextrin glycosyltransferase (EC 2.4.1.19) from Bacillus circulans has been improved. For this purpose the known sequence was built into an electron density map established by multiple isomorphous replacement and subsequent solvent-flattening at 2.5 A resolution. The resu... |
2004022 | Electrokinetic properties and surface membrane sialic acid status of platelets in idiopathic thrombocytopenic purpura (ITP). | Continuous flow electrophoresis has been used to investigate heterogeneity in the circulating platelets from patients with idiopathic thrombocytopenia (ITP) and from age- and sex-matched control donors. The ITP patients' platelet counts ranged from 15 to 80 X 10(9)/l and they had much higher mean volumes and significan... |
1900418 | The pro-polypeptide of von Willebrand factor is required for the formation of a functional factor VIII-binding site on mature von Willebrand factor. | We have established that a recombinant von Willebrand Factor (vWF) mutant (vWFdelpro) that lacks the propolypeptide, in contrast with mature wild-type vWF, with which it is identical in terms of primary amino acid sequence, is not able to form a complex with Factor VIII. Wild-type vWF (flvWF) and vWFdelpro were express... |
2001227 | Modification of host cell membrane lipid composition by the intra-erythrocytic human malaria parasite Plasmodium falciparum. | The phospholipid and fatty acid compositions of the host infected erythrocyte plasma membrane (IEPM) have been determined for erythrocytes infected with the human malaria parasite Plasmodium falciparum. IEPM were prepared by selective lysis of the host erythrocyte (but not of the parasite membranes) with 0.1% saponin, ... |
1847624 | Use of 'solid-state' promoters in the electrochemistry of cytochrome c at a gold electrode. | The direct electrochemistry of cytochrome c at a gold electrode was investigated by cyclic voltammetry using, as promoters, microperoxidase (the haem-undecapeptide obtained by hydrolysis of cytochrome c), Fe(III)-protoporphyrin IX or protoporphyrin-IX, all entrapped in a cellulose triacetate membrane. The results indic... |
1996954 | 'Slow-binding' sixth-ligand inhibitors of cytochrome P-450 aromatase. Studies with 19-thiomethyl- and 19-azido-androstenedione. | The progress curves for the inhibition of aromatase by 19-thiomethylandrostenedione and 19-azidoandrostenedione were found to be non-linear where the extent of inhibition increased with time. Further experiments enabled these compounds to be classified as 'slow-binding' inhibitors of aromatase. The phenomenon was attri... |
1899927 | Amyloid precursor protein in aged nonhuman primates. | In individuals with Alzheimer disease and in aged nonhuman primates, deposits of amyloid occur in senile plaques in brain parenchyma and in the walls of some meningeal and cortical vessels. Amyloid is primarily composed of beta/A4, a 4-kDa peptide derived from the transmembrane form of an amyloid precursor protein (APP... |
1995606 | Restoration of the calcium binding activity of mutant calmodulins toward normal by the presence of a calmodulin binding structure. | The altered calcium binding activity of calmodulins (CaM) with point mutations can be restored toward that of wild type CaMs by the formation of a complex between CaM and a CaM binding sequence. Three different site-specific mutations resulted in selective effects on the apparent stoichiometry and affinity of CaM for c... |
1825212 | Polarized expression of integrin receptors (alpha 6 beta 4, alpha 2 beta 1, alpha 3 beta 1, and alpha v beta 5) and their relationship with the cytoskeleton and basement membrane matrix in cultured human keratinocytes. | In human keratinocytes cultured in conditions which allow differentiation and stratification and are suitable to reconstitute a fully functional epidermis, alpha 6 beta 4 and two members of the beta 1 integrin family (alpha 2 beta 1 and alpha 3 beta 1) were respectively polarized to the basal and lateral domains of the... |
1993735 | Three different actin filament assemblies occur in every hair cell: each contains a specific actin crosslinking protein. | The apex of hair cells of the chicken auditory organ contains three different kinds of assemblies of actin filaments in close spatial proximity. These are (a) paracrystals of actin filaments with identical polarity in stereocilia, (b) a dense gellike meshwork of actin filaments forming the cuticular plate, and (c) a bu... |
1992484 | Kinetics of self-assembly of alpha alpha-tropomyosin coiled coils from unfolded chains. | The two-chain coiled-coil structural motif is found in fibrous muscle proteins and leucine zippers. Unfolding/refolding studies abound, but none establishes the time scale or mechanism of structural assembly from separated, unfolded chains. Stopped-flow circular dichroism studies of such refolding of alpha-tropomyosin ... |
1992462 | Negative supercoiling of DNA facilitates an interaction between transcription factor IID and the fibroin gene promoter. | Transcription of the fibroin gene can be reconstituted with partially purified components from HeLa cells. Transcription factors IIB, IID, and IIE and RNA polymerase II are required for accurate initiation of transcription. Linear and relaxed closed circular DNA show a similar level of template activity. However, trans... |
1846961 | Binary system for regulating transgene expression in mice: targeting int-2 gene expression with yeast GAL4/UAS control elements. | We have developed a binary transgenic system that activates an otherwise silent transgene in the progeny of a simple genetic cross. The system consists of two types of transgenic mouse strains, targets and transactivators. A target strain bears a transgene controlled by yeast regulatory sequences (UAS) that respond onl... |
1846702 | Inhalational anesthetics stereochemistry: optical resolution of halothane, enflurane, and isoflurane. | Halothane (I), enflurane (II), and isoflurane (III), which are among the most important inhalation anesthetics, are currently administered as racemic mixtures. The pure enantiomers have not been described, and no analytical method for resolving the commercially available racemic mixtures has been reported. Complete opt... |
1846673 | Alpha B crystallin accumulation is a specific response to Ha-ras and v-mos oncogene expression in mouse NIH 3T3 fibroblasts. | The conditional expression of the v-mos and Ha-ras(EJ) oncogenes in NIH 3T3 cells leads to the accumulation of a 23-kDa protein (p23) (R. Klemenz, S. Hoffmann, R. Jaggi, and A.-K. Werenskiold, Oncogene 4:799-803, 1989). We purified p23 to homogeneity and determined part of the amino acid sequence. The obtained sequence... |
1990011 | Bovine glomerular basement membrane. Location and structure of the asparagine-linked oligosaccharide units and their potential role in the assembly of the 7 S collagen IV tetramer. | Collagen IV contains an amino-terminal tetramerization domain (7 S) that is involved in aggregation and cross-linking as part of the process of self-assembly of the collagen IV matrix of basement membranes. We determined the structure and location of the Asn-linked oligosaccharides of the 7 S tetramer. Two glycopeptide... |
1988539 | The CD4 molecule is not always required for the T cell response to bacterial enterotoxins. | T cells respond in a V beta-restricted fashion to bacterial enterotoxins bound to major histocompatibility complex (MHC) class II molecules. The requirement for CD4 in MHC class II-restricted T cell responses is very well established. We have assessed the role of CD4 in the T cell response to the bacterial enterotoxins... |
1898972 | Differential loss of envelope glycoprotein gp120 from virions of human immunodeficiency virus type 1 isolates: effects on infectivity and neutralization. | Several parameters which may affect the infectivity of human immunodeficiency virus type 1 in tissue culture were analyzed. In particular, we used gel exclusion chromatography to investigate how the loss of the surface glycoprotein gp120 from virions of the HTLV-IIIB (IIIB), HTLV-IIIRF (RF), and SF-2 isolates modulates... |
1846187 | Structure of the herpes simplex virus capsid: effects of extraction with guanidine hydrochloride and partial reconstitution of extracted capsids. | Viral B capsids were purified from cells infected with herpes simplex virus type 1 and extracted in vitro with 2.0 M guanidine hydrochloride (GuHCl). Sodium dodecyl sulfate-polyacrylamide gel analyses demonstrated that extraction resulted in the removal of greater than 95% of capsid proteins VP22a and VP26 while there ... |
1987068 | Intracellular and extracellular enzymatic deacylation of bacterial endotoxin during localized inflammation induced by Escherichia coli. | Acyloxyacyl hydrolase (AOAH), an enzyme that removes the secondary acyl chains of gram-negative bacterial lipid A (endotoxin), has been identified previously in human neutrophils and mouse macrophages. We report here that bovine leukocytes also contain AOAH activity. Although bovine AOAH deacylates bacterial lipopolysa... |
16348415 | Homologous Streptomycin Resistance Gene Present among Diverse Gram-Negative Bacteria in New York State Apple Orchards. | The streptomycin resistance gene of Pseudomonas syringae pv. papulans Psp36 was cloned into Escherichia coli and used to develop a 500-bp DNA probe that is specific for streptomycin resistance in P. syringae pv. papulans. The probe is a portion of a 1-kb region shared by three different DNA clones of the resistance gen... |
16348407 | Physiological diversity and distributions of heterotrophic bacteria in deep cretaceous sediments of the atlantic coastal plain. | A series of 23 intact core segments was obtained from two distinct deep subsurface geological formations, the Middendorf and the Cape Fear formations, underlying the southeastern coastal plain of South Carolina. The Middendorf formation in this region consists of permeable, saturated, sandy sediments; the Cape Fear for... |
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