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| Carayon, Kevin; Leh, Herve; Henry, Etienne; Simon, Francoise; Mouscadet, Jean-francois; Deprez, Eric. |
| HIV-1 integrase catalyzes the insertion of the viral genome into chromosomal DNA. We characterized the structural determinants of the 3'-processing reaction specificity-the first reaction of the integration process-at the DNA-binding level. We found that the integrase N-terminal domain, containing a pseudo zinc-finger motif, plays a key role, at least indirectly, in the formation of specific integrase-DNA contacts. This motif mediates a cooperative DNA binding of integrase that occurs only with the cognate/viral DNA sequence and the physiologically relevant Mg(2+) cofactor. The DNA-binding was essentially non-cooperative with Mn(2+) or using non-specific/random sequences, regardless of the metallic cofactor. 2,2'-Dithiobisbenzamide-1 induced zinc ejection... |
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| Ano: 2010 |
URL: http://archimer.ifremer.fr/doc/00206/31773/30183.pdf |
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| Ralec, Celine; Henry, Etienne; Lemor, Melanie; Killelea, Tom; Henneke, Ghislaine. |
| Divalent metal ions, usually Mg2+, are required for both DNA synthesis and proofreading functions by DNA polymerases (DNA Pol). Although used as a non-reactive cofactor substitute for binding and crystallographic studies, Ca2+ supports DNA polymerization by only one DNA Pol, Dpo4. Here, we explore whether Ca2+-driven catalysis might apply to high-fidelity (HiFi) family B DNA Pols. The consequences of replacing Mg2+ by Ca2+ on base pairing at the polymerase active site as well as the editing of terminal nucleotides at the exonuclease active site of the archaeal Pyrococcus abyssi DNA Pol (PabPolB) are characterized and compared to other (families B, A, Y, X, D) DNA Pols. Based on primer extension assays, steady-state kinetics and ion-chased experiments, we... |
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| Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00405/51663/52210.pdf |
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| Li, Jiayao; Henry, Etienne; Wang, Lanmei; Delelis, Olivier; Wang, Huan; Simon, Francoise; Tauc, Patrick; Brochon, Jean-claude; Zhao, Yunlong; Deprez, Eric. |
| Fatty acid-binding proteins (FABPs) are small cytosolic proteins, largely distributed in invertebrates and vertebrates, which accomplish uptake and intracellular transport of hydrophobic ligands such as fatty acids. Although long chain fatty acids play multiple crucial roles in cellular functions (structural, energy metabolism, regulation of gene expression), the precise functions of FABPs, especially those of invertebrate species, remain elusive. Here, we have identified and characterized a novel FABP family member, Cq-FABP, from the hepatopancreas of red claw crayfish Cherax quadricarinatus. We report the characterization of fatty acid-binding affinity of Cq-FABP by four different competitive fluorescence-based assays. In the two first approaches, the... |
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| Ano: 2012 |
URL: http://archimer.ifremer.fr/doc/00206/31770/30186.pdf |
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| Lemor, Melanie; Kong, Ziqing; Henry, Etienne; Brizard, Raphael; Laurent, Sebastien; Bosse, Audrey; Henneke, Ghislaine. |
| Consistent with the fact that ribonucleotides (rNTPs) are in excess over deoxyribonucleotides (dNTPs) in vivo, recent findings indicate that replicative DNA polymerases (DNA Pols) are able to insert ribonucleotides (rNMPs) during DNA synthesis, raising crucial questions about the fidelity of DNA replication in both Bacteria and Eukarya. Here, we report that the level of rNTPs is 20-fold higher than that of dNTPs in Pyrococcus abyssi cells. Using dNTP and rNTP concentrations present in vivo, we recorded rNMP incorporation in a template-specific manner during in vitro synthesis, with the family-D DNA Pol (PolD) having the highest propensity compared with the family-B DNA Pol and the p41/p46 complex. We also showed that ribonucleotides accumulate at a... |
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Palavras-chave: Archaea; DNA replication and repair; DNA polymerase; Nucleotide pool; Translesion synthesis. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00464/57603/59796.pdf |
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| Qin, Wei; Bazeille, Nicolas; Henry, Etienne; Zhang, Bo; Deprez, Eric; Xi, Xu-guang. |
| Cadmium is a toxic metal that inactivates DNA-repair proteins via multiple mechanisms, including zinc substitution. In this study, we investigated the effect of Cd2+ on the Bloom protein (BLM), a DNA-repair helicase carrying a zinc-binding domain (ZBD) and playing a critical role to ensure genomic stability. One characteristics of BLM-deficient cells is the elevated rate of sister chromatid exchanges, a phenomenon that is also induced by Cd2+. Here, we show that Cd2+ strongly inhibits both ATPase and helicase activities of BLM. Cd2+ primarily prevents BLM-DNA interaction via its binding to sulfhydryl groups of solvent-exposed cysteine residues and, concomitantly, promotes the formation of large BLM multimers/aggregates. In contrast to previously described... |
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| Ano: 2016 |
URL: https://archimer.ifremer.fr/doc/00341/45196/44599.pdf |
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| Chennoufi, Rahima; Bougherara, Houcine; Gagey-eilstein, Nathalie; Dumat, Blaise; Henry, Etienne; Subra, Frederic; Bury-mone, Stephanie; Mahuteau-betzer, Florence; Tauc, Patrick; Teulade-fichou, Marie-paule; Deprez, Eric. |
| Photodynamic therapy (PDT) leads to cell death by using a combination of a photosensitizer and an external light source for the production of lethal doses of reactive oxygen species (ROS). Since a major limitation of PDT is the poor penetration of UV-visible light in tissues, there is a strong need for organic compounds whose activation is compatible with near-infrared excitation. Triphenylamines (TPAs) are fluorescent compounds, recently shown to efficiently trigger cell death upon visible light irradiation (458 nm), however outside the so-called optical/therapeutic window. Here, we report that TPAs target cytosolic organelles of living cells, mainly mitochondria, triggering a fast apoptosis upon two-photon excitation, thanks to their large two-photon... |
| Tipo: Text |
Palavras-chave: Apoptosis; Small molecules. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00320/43168/42726.pdf |
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| Hogrel, Gaelle; Lu, Yang; Laurent, Sebastien; Henry, Etienne; Etienne, Clarisse; Duy Khanh Phung,; Dulermo, Remi; Bosse, Audrey; Pluchon, Pierre Francois; Clouet-d'Orval, Beatrice; Flament, Didier. |
| Several archaeal species prevalent in extreme environments are particularly exposed to factors likely to cause DNA damages. These include hyperthermophilic archaea (HA), living at temperatures >70°C, which arguably have efficient strategies and robust genome guardians to repair DNA damage threatening their genome integrity. In contrast to Eukarya and other archaea, homologous recombination appears to be a vital pathway in HA, and the Mre11–Rad50 complex exerts a broad influence on the initiation of this DNA damage response process. In a previous study, we identified a physical association between the Proliferating Cell Nuclear Antigen (PCNA) and the Mre11–Rad50 (MR) complex. Here, by performing co-immunoprecipitation and SPR analyses, we identified a... |
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| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00439/55092/56534.pdf |
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| Raia, Pierre; Carroni, Marta; Henry, Etienne; Pehau-arnaudet, Gerard; Brule, Sebastien; Beguin, Pierre; Henneke, Ghislaine; Lindahl, Erik; Delarue, Marc; Sauguet, Ludovic. |
| PolD is an archaeal replicative DNA polymerase (DNAP) made of a proofreading exonuclease subunit (DP1) and a larger polymerase catalytic subunit (DP2). Recently, we reported the individual crystal structures of the DP1 and DP2 catalytic cores, thereby revealing that PolD is an atypical DNAP that has all functional properties of a replicative DNAP but with the catalytic core of an RNA polymerase (RNAP). We now report the DNA-bound cryo–electron microscopy (cryo-EM) structure of the heterodimeric DP1–DP2 PolD complex from Pyrococcus abyssi, revealing a unique DNA-binding site. Comparison of PolD and RNAPs extends their structural similarities and brings to light the minimal catalytic core shared by all cellular transcriptases. Finally, elucidating the... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00477/58883/61420.pdf |
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