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Immunologie, Immunopathologie et Chimie Thérapeutique
Publications
2013
Schaeffer Evelyne, Dehuyser Laure, Sigwalt David, Flacher Vincent, Bernacchi Serena, Chaloin Olivier, Remy Jean-Serge, Mueller Christopher G, Baati Rachid, Wagner Alain
Dynamic micelles of mannoside glycolipids are more efficient than polymers for inhibiting HIV-1 trans-infection Article de journal
Dans: Bioconjugate Chemistry, vol. 24, no. 11, p. 1813–1823, 2013, ISSN: 1520-4812.
Résumé | Liens | BibTeX | Étiquettes: Anti-HIV Agents, Calcium, Cells, Chemistry, Cultured, Dendritic Cells, Dose-Response Relationship, Drug, Electron, fluorescence, Glycolipids, HIV, HIV Infections, HIV-1, Human, Humans, immunodeficiency, immunopathology, inhibition, LECTIN, Lectins, lipid, Mannosides, Micelles, Microbial Sensitivity Tests, Microscopy, Models, Molecular, Molecular Structure, Polymers, prophylaxis, Spectrometry, Structure-Activity Relationship, Surface Plasmon Resonance, target, Team-Mueller, Thermodynamics, Transmission, virus
@article{schaeffer_dynamic_2013,
title = {Dynamic micelles of mannoside glycolipids are more efficient than polymers for inhibiting HIV-1 trans-infection},
author = {Evelyne Schaeffer and Laure Dehuyser and David Sigwalt and Vincent Flacher and Serena Bernacchi and Olivier Chaloin and Jean-Serge Remy and Christopher G Mueller and Rachid Baati and Alain Wagner},
doi = {10.1021/bc4000806},
issn = {1520-4812},
year = {2013},
date = {2013-11-01},
journal = {Bioconjugate Chemistry},
volume = {24},
number = {11},
pages = {1813--1823},
abstract = {Mannoside glycolipid conjugates are able to inhibit human immunodeficiency virus type 1 (HIV-1) trans-infection mediated by human dendritic cells (DCs). The conjugates are formed by three building blocks: a linear or branched mannose head, a hydrophilic linker, and a 24-carbon lipid chain. We have shown that, even as single molecules, these compounds efficiently target mannose-binding lectins, such as DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN) important for HIV-1 transmission. With the goal to optimize their inhibitory activity by supramolecular structure formation, we have compared saturated and unsaturated conjugates, as single molecules, self-assemblies of dynamic micelles, and photopolymerized cross-linked polymers. Surface plasmon resonance showed that, unexpectedly, polymers of trivalent conjugates did not display a higher binding affinity for DC-SIGN than single molecules. Interactions on a chip or in solution were independent of calcium; however, binding to DCs was inhibited by a calcium chelator. Moreover, HIV-1 trans-infection was mostly inhibited by dynamic micelles and not by rigid polymers. The inhibition data revealed a clear correlation between the structure and molecular assembly of a conjugate and its biological antiviral activity. We present an interaction model between DC-SIGN and conjugates-either single molecules, micelles, or polymers-that highlights that the most effective interactions by dynamic micelles involve both mannose heads and lipid chains. Our data reveal that trivalent glycolipid conjugates display the highest microbicide potential for HIV prophylaxis, as dynamic micelles conjugates and not as rigid polymers.},
keywords = {Anti-HIV Agents, Calcium, Cells, Chemistry, Cultured, Dendritic Cells, Dose-Response Relationship, Drug, Electron, fluorescence, Glycolipids, HIV, HIV Infections, HIV-1, Human, Humans, immunodeficiency, immunopathology, inhibition, LECTIN, Lectins, lipid, Mannosides, Micelles, Microbial Sensitivity Tests, Microscopy, Models, Molecular, Molecular Structure, Polymers, prophylaxis, Spectrometry, Structure-Activity Relationship, Surface Plasmon Resonance, target, Team-Mueller, Thermodynamics, Transmission, virus},
pubstate = {published},
tppubtype = {article}
}
Mannoside glycolipid conjugates are able to inhibit human immunodeficiency virus type 1 (HIV-1) trans-infection mediated by human dendritic cells (DCs). The conjugates are formed by three building blocks: a linear or branched mannose head, a hydrophilic linker, and a 24-carbon lipid chain. We have shown that, even as single molecules, these compounds efficiently target mannose-binding lectins, such as DC-specific ICAM-3-grabbing nonintegrin (DC-SIGN) important for HIV-1 transmission. With the goal to optimize their inhibitory activity by supramolecular structure formation, we have compared saturated and unsaturated conjugates, as single molecules, self-assemblies of dynamic micelles, and photopolymerized cross-linked polymers. Surface plasmon resonance showed that, unexpectedly, polymers of trivalent conjugates did not display a higher binding affinity for DC-SIGN than single molecules. Interactions on a chip or in solution were independent of calcium; however, binding to DCs was inhibited by a calcium chelator. Moreover, HIV-1 trans-infection was mostly inhibited by dynamic micelles and not by rigid polymers. The inhibition data revealed a clear correlation between the structure and molecular assembly of a conjugate and its biological antiviral activity. We present an interaction model between DC-SIGN and conjugates-either single molecules, micelles, or polymers-that highlights that the most effective interactions by dynamic micelles involve both mannose heads and lipid chains. Our data reveal that trivalent glycolipid conjugates display the highest microbicide potential for HIV prophylaxis, as dynamic micelles conjugates and not as rigid polymers.
2008
Geary C., Baudrey S., Jaeger L.
Comprehensive features of natural and in vitro selected GNRA tetraloop-binding receptors Article de journal
Dans: Nucleic Acids Res, vol. 36, no. 4, p. 1138-52, 2008, (1362-4962 (Electronic) Journal Article Research Support, N.I.H., Extramural Research Support, U.S. Gov't, Non-P.H.S.).
Résumé | BibTeX | Étiquettes: Acid, Adenine/chemistry, Analysis, Base, Conformation, Data, dimerization, directed, Evolution, KROL, Models, Molecular, Nucleic, RNA, RNA/*chemistry/classification, Sequence, Thermodynamics
@article{,
title = {Comprehensive features of natural and in vitro selected GNRA tetraloop-binding receptors},
author = { C. Geary and S. Baudrey and L. Jaeger},
year = {2008},
date = {2008-01-01},
journal = {Nucleic Acids Res},
volume = {36},
number = {4},
pages = {1138-52},
abstract = {Specific recognitions of GNRA tetraloops by small helical receptors are among the most widespread long-range packing interactions in large ribozymes. However, in contrast to GYRA and GAAA tetraloops, very few GNRA/receptor interactions have yet been identified to involve GGAA tetraloops in nature. A novel in vitro selection scheme based on a rigid self-assembling tectoRNA scaffold designed for isolation of intermolecular interactions with A-minor motifs has yielded new GGAA tetraloop-binding receptors with affinity in the nanomolar range. One of the selected receptors is a novel 12 nt RNA motif, (CCUGUG. AUCUGG), that recognizes GGAA tetraloop hairpin with a remarkable specificity and affinity. Its physical and chemical characteristics are comparable to those of the well-studied '11nt' GAAA tetraloop receptor motif. A second less specific motif (CCCAGCCC. GAUAGGG) binds GGRA tetraloops and appears to be related to group IC3 tetraloop receptors. Mutational, thermodynamic and comparative structural analysis suggests that natural and in vitro selected GNRA receptors can essentially be grouped in two major classes of GNRA binders. New insights about the evolution, recognition and structural modularity of GNRA and A-minor RNA-RNA interactions are proposed.},
note = {1362-4962 (Electronic)
Journal Article
Research Support, N.I.H., Extramural
Research Support, U.S. Gov't, Non-P.H.S.},
keywords = {Acid, Adenine/chemistry, Analysis, Base, Conformation, Data, dimerization, directed, Evolution, KROL, Models, Molecular, Nucleic, RNA, RNA/*chemistry/classification, Sequence, Thermodynamics},
pubstate = {published},
tppubtype = {article}
}
Specific recognitions of GNRA tetraloops by small helical receptors are among the most widespread long-range packing interactions in large ribozymes. However, in contrast to GYRA and GAAA tetraloops, very few GNRA/receptor interactions have yet been identified to involve GGAA tetraloops in nature. A novel in vitro selection scheme based on a rigid self-assembling tectoRNA scaffold designed for isolation of intermolecular interactions with A-minor motifs has yielded new GGAA tetraloop-binding receptors with affinity in the nanomolar range. One of the selected receptors is a novel 12 nt RNA motif, (CCUGUG. AUCUGG), that recognizes GGAA tetraloop hairpin with a remarkable specificity and affinity. Its physical and chemical characteristics are comparable to those of the well-studied '11nt' GAAA tetraloop receptor motif. A second less specific motif (CCCAGCCC. GAUAGGG) binds GGRA tetraloops and appears to be related to group IC3 tetraloop receptors. Mutational, thermodynamic and comparative structural analysis suggests that natural and in vitro selected GNRA receptors can essentially be grouped in two major classes of GNRA binders. New insights about the evolution, recognition and structural modularity of GNRA and A-minor RNA-RNA interactions are proposed.
2004
Przykorska A., Solecka K., Olszak K., Keith G., Nawrot B., Kuligowska E.
Wheat (Triticum vulgare) chloroplast nuclease ChSI exhibits 5' flap structure-specific endonuclease activity Article de journal
Dans: Biochemistry, vol. 43, no. 35, p. 11283-94, 2004, (0006-2960 Journal Article).
Résumé | BibTeX | Étiquettes: &, Acid, Catalysis, Chloroplasts/*enzymology, Conformation, Desorption-Ionization, DNA, Endonucleases/*chemistry/isolation, Exonucleases/chemistry/metabolism, Flap, Gov't, Hydrolysis, KEITH, Kinetics, Laser, Mass, Matrix-Assisted, Non-U.S., Nucleic, Oligonucleotides/chemical, Plant/chemistry/metabolism, purification/*metabolism, Relationship, Single-Stranded/chemistry/metabolism, Specificity, Spectrometry, Structure-Activity, Substrate, Support, synthesis/metabolism, Thermodynamics, Triticum/*enzymology
@article{,
title = {Wheat (Triticum vulgare) chloroplast nuclease ChSI exhibits 5' flap structure-specific endonuclease activity},
author = { A. Przykorska and K. Solecka and K. Olszak and G. Keith and B. Nawrot and E. Kuligowska},
year = {2004},
date = {2004-01-01},
journal = {Biochemistry},
volume = {43},
number = {35},
pages = {11283-94},
abstract = {The structure-specific ChSI nuclease from wheat (Triticum vulgare) chloroplast stroma has been previously purified and characterized in our laboratory. It is a single-strand-specific DNA and RNA endonuclease. Although the enzyme has been initially characterized and used as a structural probe, its biological function is still unknown. Localization of the ChSI enzyme inside chloroplasts, possessing their own DNA that is generally highly exposed to UV light and often affected by numerous redox reactions and electron transfer processes, might suggest, however, that this enzyme could be involved in DNA repair. The repair of some types of DNA damage has been shown to proceed through branched DNA intermediates which are substrates for the structure-specific DNA endonucleases. Thus we tested the substrate specificity of ChSI endonuclease toward various branched DNAs containing 5' flap, 5' pseudoflap, 3' pseudoflap, or single-stranded bulged structural motifs. It appears that ChSI has a high 5' flap structure-specific endonucleolytic activity. The catalytic efficiency (k(cat)/K(M)) of the enzyme is significantly higher for the 5' flap substrate than for single-stranded DNA. The ChSI 5' flap activity was inhibited by high concentrations of Mg(2+), Mn(2+), Zn(2+), or Ca(2+). However, low concentrations of divalent cations could restore the loss of ChSI activity as a consequence of EDTA pretreatment. In contrast to other known 5' flap nucleases, the chloroplast enzyme ChSI does not possess any 5'-->3' exonuclease activity on double-stranded DNA. Therefore, we conclude that ChSI is a 5' flap structure-specific endonuclease with nucleolytic activity toward single-stranded substrates.},
note = {0006-2960
Journal Article},
keywords = {&, Acid, Catalysis, Chloroplasts/*enzymology, Conformation, Desorption-Ionization, DNA, Endonucleases/*chemistry/isolation, Exonucleases/chemistry/metabolism, Flap, Gov't, Hydrolysis, KEITH, Kinetics, Laser, Mass, Matrix-Assisted, Non-U.S., Nucleic, Oligonucleotides/chemical, Plant/chemistry/metabolism, purification/*metabolism, Relationship, Single-Stranded/chemistry/metabolism, Specificity, Spectrometry, Structure-Activity, Substrate, Support, synthesis/metabolism, Thermodynamics, Triticum/*enzymology},
pubstate = {published},
tppubtype = {article}
}
The structure-specific ChSI nuclease from wheat (Triticum vulgare) chloroplast stroma has been previously purified and characterized in our laboratory. It is a single-strand-specific DNA and RNA endonuclease. Although the enzyme has been initially characterized and used as a structural probe, its biological function is still unknown. Localization of the ChSI enzyme inside chloroplasts, possessing their own DNA that is generally highly exposed to UV light and often affected by numerous redox reactions and electron transfer processes, might suggest, however, that this enzyme could be involved in DNA repair. The repair of some types of DNA damage has been shown to proceed through branched DNA intermediates which are substrates for the structure-specific DNA endonucleases. Thus we tested the substrate specificity of ChSI endonuclease toward various branched DNAs containing 5' flap, 5' pseudoflap, 3' pseudoflap, or single-stranded bulged structural motifs. It appears that ChSI has a high 5' flap structure-specific endonucleolytic activity. The catalytic efficiency (k(cat)/K(M)) of the enzyme is significantly higher for the 5' flap substrate than for single-stranded DNA. The ChSI 5' flap activity was inhibited by high concentrations of Mg(2+), Mn(2+), Zn(2+), or Ca(2+). However, low concentrations of divalent cations could restore the loss of ChSI activity as a consequence of EDTA pretreatment. In contrast to other known 5' flap nucleases, the chloroplast enzyme ChSI does not possess any 5'-->3' exonuclease activity on double-stranded DNA. Therefore, we conclude that ChSI is a 5' flap structure-specific endonuclease with nucleolytic activity toward single-stranded substrates.
1992
Bonmatin J M, Bonnat J L, Gallet X, Vovelle F, Ptak M, Reichhart Jean-Marc, Hoffmann Jules A, Keppi E, Legrain M, Achstetter T
Two-dimensional 1H NMR study of recombinant insect defensin A in water: resonance assignments, secondary structure and global folding Article de journal
Dans: J. Biomol. NMR, vol. 2, no. 3, p. 235–256, 1992, ISSN: 0925-2738.
Résumé | BibTeX | Étiquettes: Animals, Defensins, hoffmann, Hydrogen, Insect Hormones, insects, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Protein Conformation, Recombinant Proteins, reichhart, Saccharomyces cerevisiae, Thermodynamics
@article{bonmatin_two-dimensional_1992,
title = {Two-dimensional 1H NMR study of recombinant insect defensin A in water: resonance assignments, secondary structure and global folding},
author = {J M Bonmatin and J L Bonnat and X Gallet and F Vovelle and M Ptak and Jean-Marc Reichhart and Jules A Hoffmann and E Keppi and M Legrain and T Achstetter},
issn = {0925-2738},
year = {1992},
date = {1992-01-01},
journal = {J. Biomol. NMR},
volume = {2},
number = {3},
pages = {235--256},
abstract = {A 500 MHz 2D 1H NMR study of recombinant insect defensin A is reported. This defense protein of 40 residues contains 3 disulfide bridges, is positively charged and exhibits antibacterial properties. 2D NMR maps of recombinant defensin A were fully assigned and secondary structure elements were localized. The set of NOE connectivities, 3JNH-alpha H coupling constants as well as 1H/2H exchange rates and delta delta/delta T temperature coefficients of NH protons strongly support the existence of an alpha-helix (residues 14-24) and of an antiparallel beta-sheet (residues 27-40). Models of the backbone folding were generated by using the DISMAN program and energy refined by using the AMBER program. This was done on the basis of: (i) 133 selected NOEs, (ii) 21 dihedral restraints from 3JNH-alpha H coupling constants, (iii) 12 hydrogen bonds mostly deduced from 1H/2H exchange rates or temperature coefficients, in addition to 9 initial disulfide bridge covalent constraints. The two secondary structure elements and the two bends connecting them involve approximately 70% of the total number of residues, which impose some stability in the C-terminal part of the molecule. The remaining N-terminal fragment forms a less well defined loop. This spatial organization, in which a beta-sheet is linked to an alpha-helix by two disulfide bridges and to a large loop by a third disulfide bridge, is rather similar to that found in scorpion charybdotoxin and seems to be partly present in several invertebrate toxins.},
keywords = {Animals, Defensins, hoffmann, Hydrogen, Insect Hormones, insects, M3i, Magnetic Resonance Spectroscopy, Models, Molecular, Protein Conformation, Recombinant Proteins, reichhart, Saccharomyces cerevisiae, Thermodynamics},
pubstate = {published},
tppubtype = {article}
}
A 500 MHz 2D 1H NMR study of recombinant insect defensin A is reported. This defense protein of 40 residues contains 3 disulfide bridges, is positively charged and exhibits antibacterial properties. 2D NMR maps of recombinant defensin A were fully assigned and secondary structure elements were localized. The set of NOE connectivities, 3JNH-alpha H coupling constants as well as 1H/2H exchange rates and delta delta/delta T temperature coefficients of NH protons strongly support the existence of an alpha-helix (residues 14-24) and of an antiparallel beta-sheet (residues 27-40). Models of the backbone folding were generated by using the DISMAN program and energy refined by using the AMBER program. This was done on the basis of: (i) 133 selected NOEs, (ii) 21 dihedral restraints from 3JNH-alpha H coupling constants, (iii) 12 hydrogen bonds mostly deduced from 1H/2H exchange rates or temperature coefficients, in addition to 9 initial disulfide bridge covalent constraints. The two secondary structure elements and the two bends connecting them involve approximately 70% of the total number of residues, which impose some stability in the C-terminal part of the molecule. The remaining N-terminal fragment forms a less well defined loop. This spatial organization, in which a beta-sheet is linked to an alpha-helix by two disulfide bridges and to a large loop by a third disulfide bridge, is rather similar to that found in scorpion charybdotoxin and seems to be partly present in several invertebrate toxins.