Mostrando recursos 1 - 20 de 39

  1. Molecular cloning, sequencing, and expression in Escherichia coli of human preprourokinase cDNA

    Jacobs, P.; Cravador, A.; Loriau, R.; Brockly, F.; Colau, B.; Chuchana, P.; Van Elsen, A.; Herzog, A.; Bollen, A.
    A cDNA library derived from human carcinoma cells was used to isolate a clone, pULB1000, coding for the preproenzyme form of human urokinase. This clone carries the full-length sequence coding for the signal peptide and for the A chain (157 amino acids) and B chain (253 amino acids) of urokinase in tandem. The sequence of the cDNA predicts the presence of a single lysine residue between the last amino acid of the mature A polypeptide (Phe-157) and the first amino acid of the mature B polypeptide (Ile-1). The amino acid sequence deduced from the cDNA sequence fits the published amino...

  2. Unusual reactivity of selenoboranes towards epoxides: New selective routes to beta- hydroxyselenides and allylalcohols

    Cravador, A.; Krief, A.
    Selenoboranes react with terminal, α, β-di- and trisubstituted epoxides to produce β-hydroxyselenides (or olefins) in the two first cases and allyl alcohols in the last one. A very high stereodescrimination has been observed for α, β-bisubstituted epoxides: the cis epoxide being much more reactive.

  3. CRYSTALLIZATION AND PRELIMINARY-X-RAY DIFFRACTION ANALYSIS OF TETRA-HEME CYTOCHROME-C(3) FROM SULFATE-REDUCING AND NITRATE-REDUCING DESULFOVIBRIO-DESULFURICANS ATCC-27774

    Frazao, C; Cravador, A.; Matias, Pm; Carrondo, Ma
    Crystals of the tetra-heme cytochrome C3 (M(r) = 13 kDa, 107 residues, four heme groups) from sulfate- and nitrate-reducing Desulfovibrio desulfuricans ATCC 27774 have been obtained and crystallographically characterized. They belong to space group P6(1)22 with cell dimensions a = b = 61.84 (4) and c = 109.7 (2) angstrom, and z = 12. Intensity data were initially collected on a FAST system with a rotating-anode X-ray source leading to a total of 22 592 observations, from which only 4930 were unique, in the resolution range 20.0-2.4 angstrom with an R(merge)(I) of 7.0%. Higher resolution data were measured on a...

  4. Molecular cloning of two genes induced by alpha-interferon in human cells.

    Moutschen, S; Wathelet, M; Cravador, A.; Defilippi, P; Huez, G; Content, J

  5. Synthesis of selenoacetals

    Clarembeau, M.; Cravador, A.; Dumont, W.; Hevesi, L.; Krief, A.; Lucchetti, J.; Vanende, D.
    This paper reports our results concerning the syntheses of various bis(alkylseleno)alkanes and some of their arylseleno analogues by different methods. The scope and limitation of each of them are presented.

  6. Molecular cloning, full-length sequence and preliminary characterization of a 56-kDa protein induced by human interferons

    Wathelet, M.; Moutschen, S.; Defilippi, P.; Cravador, A.; Collet, M.; Huez, G.; Content, J.
    Among the various proteins which are induced when human cells are are treatened with interferon, a predominant protein of unknown function, with molecular mass 56 kDa, has been observed. With the aim of exploring the molecular basis of the regulation of this protein and of its mRNA, in order to understand its biological functionand its possible contribution to the various antiviral and non-antiviral actions exerted by interferons.

  7. Two novel alkaloids from american ladybug Hippodamia-convergens (coleoptera, coccinellidae)

    Tursch, B.; Daloze, D.; Pasteels, J. M.; Cravador, A.; Braekman, J. C.; Hootele, C.; Zimmermann, D.

  8. Full-length sequence and expression of the 42 kDa 2-5A synthetase induced by human interferon

    Wathelet, M; Moutschen, S; Cravador, A.; Dewit, L; Defilippi, P; Huez, G; Content, J
    Interferon-induced 2-5A synthetases are probably involved in some antiviral actions of interferon. In human cells two different mRNAs (1.6, 1.8 kb long) coding for this protein are transcribed from the same gene and are produced by differential splicing. The relationship between the two mRNAs of different size and the active enzyme is not clear, nor is the cellular localization of the latter known. We have cloned a cDNA corresponding to the 1.6 kb RNA. This cDNA was sequenced and its complete coding region was subcloned into pSP64. The resulting plasmid was used to direct the synthesis of micrograms of capped...

  9. Chemical ecology of arthropods. 9. Structure and absolute configuration of hippodamine and convergine, two novel alkaloids from american ladybug hippodamia convergens (coleoptera- coccinellidae)

    Tursch, B.; Daloze, D.; Braekman, J. C.; Hootele, C.; Cravador, A.; Losman, D.; Karlsson, R.
    In a previous communication (2) the isolation of two defensive alkaloid, hippodamine and convergine, from the American ladybug Hippodamia convergens was reported. A preliminary chemical study (2) led to the hypothesis that hippodamine could be represented by (1), with unknown stereochemistry at carbon atom 2. Convergine was supposed to be a 3a or 6a hydroxyhippodamine.

  10. Antisense synthetic DNA

    Cravador, A.
    One old dream of the chemist in the field of the drug research is to create molecules capable of reaching their target with the precision of a missile. To accomplish it these molecules must have the propriety of distinguishing qualitative differences between healthy and diseased cells. A therapy based on this principle, able of eradicating specifically defective cells, or cells affected by a pathogen has an enormous advantage with the regard to the classical approach in which the cytotoxic drugs merely exploit quantitative biochemical and kinetic differences between abnormal and normal cells. We present in this article a review on...

  11. Porcine D-amino acid oxidase: determination of the mRNA nucleotide sequence by the characterization of genomic and cDNA clones

    Jacobs, P.; Brockly, F.; Massaer, M.; Loriau, R.; Guillaume, J. P.; Ciccarelli, E.; Heinderyckx, M.; Cravador, A.; Biemans, R.; Van Elsen, A.; Herzog, A; Bollen, A.
    Oligodeoxynucleotide probes derived from the published amino acid (aa) sequence for D-amino acid oxidase (DAO) [Ronchi et al. J. Biol. Chem. 259 (1982) 8824-8834] were used to screen cDNA libraries made from porcine kidney cortex and liver. Whereas no clones were obtained from kidney mRNAs, 20 independent ones were isolated from the liver library. Surprisingly, all of them carried only partial cDNAs for DAO starting around aa 100 in the coding sequence and extending for up to 250 bp in the 3'-noncoding sequence. One of these clones, pULB9103, was used to screen a porcine genomic library and allowed the isolation...

  12. NEW SYNTHESES OF METHYLSELENO-ACETALS AND KETALS

    Cravador, A.; Krief, A

  13. High-level production of fully active human alpha 1-antitrypsin in Escherichia coli.

    Johansen, H; Sutiphong, J; Sathe, G; Jacobs, P; Cravador, A.; Bollen, A; Rosenberg, M; Shatzman, A
    The human alpha-1-antitrypsin (A1AT) gene expressed in Escherichia coli as a full-length, non-fusion gene product accumulates to a relatively low level approaching less than or equal to 0.1% of total cellular protein. In contrast, deletion of the first 5, 10 or 15 codons leads to production of truncated A1AT derivatives at levels between 10 and 30% of total cellular protein. The protein with the largest truncation was insoluble and inactive following solubilization by chaotropic agents. In contrast, the two derivatives with the smaller truncations were found to be soluble, and exhibit identical specific activities in both trypsin and elastase inhibition...

  14. Cleavage (deprotection) of selenoacetals to carbonyl compoundes: a comparative study

    Burton, A.; Hevesi, L.; Dumont, W.; Cravador, A.; Krief, A.
    Phenyl and methyls (1) have found increasing interest in organic synthesis. They have been prepared from aldehydes or ketones (2) and selenols, from 1,1-bis(phenylseleno)-alkanes, and from 1,1,1-tris(seleno)-alkanes (5).

  15. The neurotrophic factor neuroleukin is 90% homologous with phosphohexose isomerase

    Chaput, M; Claes, V; Portetelle, D; Cludts, I; Cravador, A.; Burny, A; Gras, H; Tartar, A
    Neuroleukin (NLK) is a protein of relative molecular mass (M(r)) 56,000 (56K) secreted by denervated rat muscle and found in large amounts in muscle, brain, heart and kidneys. The protein is a neurotrophic factor for spinal and sensory neurons and a lymphokine product of lectin-stimulated T-cells. It also induces immunoglobulin secretion by human mononuclear cells. Molecular clones of NLK have been expressed in monkey COS cells and the product was shown to have the same biological and biochemical properties as the extracted protein. NLK is abundant in muscle, brain and kidney, but is active at concentrations of 10-9 to 10-11...

  16. Unexpectedly easy formation of alpha-seleno-carbonyl compounds from vinyl selenides

    Cravador, A.; Krief, A.
    Seleno-carbonyl compounds are formed on reaction of seleninic acid or anhydride with vinyl selenides and vinyl sulphides.

  17. Electrostatic calculations on fungal elicitins.

    Martel, Pj; Rodrigues, L; Cravador, A.

  18. Selective detection of human papilloma virus DNAs by specific synthetic DNA probes

    Cravador, A.; Herzog, A.; Houard, S.; D'ippolito, P.; Carroll, R.; Bollen, A.
    Specific oligodeoxynucleotide probes ranging from 20 to 35 nucleotides were defined to differentiate each of the HPV1a, 5, 6b, 8, 11, 16, 18 and 33. They were chosen using computer programs developed to compare simultaneously several 8000 bp long DNA sequences. Sequences common to all and to specific groups of the HPV DNA were also selected. Specificity of 32P-labelled probes for HPV6b, 11, 16, 18 and 33 was demonstrated and the sensitivity of the assays was evaluated by filter hybridization with viral clones and with DNA from cervical tumor biopsies. © 1989.

  19. Reduction vs acetalisation of some carbonyl-compounds by means of methylselenol and lewis-acids

    Cravador, A.; Krief, A.; Hevesi, L.
    Aliphatic ketones and aromatic carbonyl compounds on reaction with methylselenol :and a Lewis acid, are shown to undergo acetalisation and/or reduction to methyl selenide, the unexpected reduction reaction being predominant in most cases.

  20. Structure of beta-cinnamomin, a protein toxic to some plant species

    Rodrigues, M.; Archer, Margarida; Martel, P.; Jacquet, Alain; Cravador, A.; Carrondo, Maria A.
    Phytophthora and Pythium species are among the most aggressive plant pathogens, as they invade many economically important crops and forest trees. They secrete large amounts of 10 kDa proteins called elicitins that can act as elicitors of plant defence mechanisms. These proteins may also induce a hypersensitive response (HR) including plant cell necrosis, with different levels of toxicity depending on their pI. Recent studies showed that elicitins function as sterol carrier proteins. The crystallographic structure of the highly necrotic recombinant beta-cinnamomin (beta-CIN) from Phytophthora cinnamomi has been determined at 1.8 Angstrom resolution using the molecular-replacement method. beta-CIN has the same...

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