A5028438991- Cancer therapeutics and mechanisms
- DNA Repair Mechanisms
- Antibiotic Resistance in Bacteria
- Bacteriophages and microbial interactions
- DNA and Nucleic Acid Chemistry
- Bioactive Compounds and Antitumor Agents
- Synthesis and Biological Evaluation
- Polyomavirus and related diseases
- Genomics and Phylogenetic Studies
- Fungal and yeast genetics research
- Probiotics and Fermented Foods
- Gut microbiota and health
- Liver Disease Diagnosis and Treatment
- Environmental DNA in Biodiversity Studies
- Heat shock proteins research
- Synthesis and bioactivity of alkaloids
- Bacterial Genetics and Biotechnology
- Advanced biosensing and bioanalysis techniques
- Phytochemistry and biological activity of medicinal plants
- Plant Virus Research Studies
- Evolution and Genetic Dynamics
- Pharmacological Effects of Natural Compounds
- Microbial Community Ecology and Physiology
- RNA and protein synthesis mechanisms
- Genomics and Chromatin Dynamics
Institut de Biologie Intégrative de la Cellule
2016-2022
Centre National de la Recherche Scientifique
1994-2019
Université Paris-Sud
1993-2019
Université Paris-Saclay
2017-2019
CEA Paris-Saclay
2017
Commissariat à l'Énergie Atomique et aux Énergies Alternatives
2017
Laboratoire de Microbiologie et Génétique Moléculaires
2005
Biology of Extremophiles Laboratory
1993
The eocyte hypothesis, in which Eukarya emerged from within Archaea, has been boosted by the description of a new candidate archaeal phylum, "Lokiarchaeota", metagenomic data. branch Lokiarchaeota tree reconstructed concatenation 36 universal proteins. However, individual phylogenies revealed that lokiarchaeal proteins sequences have different evolutionary histories. markers at least two subsets proteins, either supporting Woese or Eocyte life. Strikingly, removal single protein, elongation...
A type II DNA topoisomerase has been purified to homogeneity from the hyperthermophilic archaeon Sulfolobus shibatae. The enzyme is composed of two subunits 60 and 47 kDa. It a Stokes radius 69 sedimentation coefficient 7.8 S which gives calculated native molecular mass approximately 230 kDa, indicating heterotetrameric structure. This ATP Mg2+ dependent can relax both negatively positively supercoiled DNA, but presents no supercoiling activity. S. shibatae more efficient in decatenation...
The beta-glucuronidase activities of bacterial strains isolated from the rat intestinal tract were studied both in vitro culture media and vivo contents gnotobiotic rats. Only 50 407 tested found to be positive vitro. They belonged three genera Clostridium, Peptostreptococcus, Staphylococcus. vitro-negative also negative vivo. generally greater than highest intact cells soluble fractions prepared disrupted pellets. There was a discrepancy between obtained conventional rats harboring selected...
The Kae1 (Kinase-associated endopeptidase 1) protein is a member of the recently identified transcription complex EKC and telomeres maintenance KEOPS in yeast. homologues are encoded by all sequenced genomes three domains life. Although annotated as putative endopeptidases, actual functions these universal proteins unknown. Here we show that purified (Pa-Kae1) from Pyrococcus abyssi an iron-protein with novel type ATP-binding site. Surprisingly, this did not exhibit activity vitro but binds...
Abstract New N ‐alkylaminoacridine derivatives attached to nitrogen heterocycles were synthesized, and their antimalarial potency was examined. They tested in vitro against the growth of Plasmodium falciparum , including chloroquine (CQ)‐susceptible CQ‐resistant strains. This biological evaluation has shown that presence a heterocyclic ring significantly increases activity P. . The best compound shows nanomolar IC 50 value toward parasite proliferation on both CQ‐susceptible these new...
Eukaryotic topoisomerases I (TOP1) are ubiquitous enzymes removing DNA torsional stress. However, there is little data concerning the three-dimensional structure of TOP1 in absence DNA, nor how molecule can enter/exit its closed conformation. Here, we solved thermostable archaeal Caldiarchaeum subterraneum CsTOP1 an apo-form. The enzyme displays open conformation resulting from one substantial rotation between capping (CAP) and catalytic (CAT) modules. junction these two modules a...
DNA topoisomerase VI from the hyperthermophilic archaeon Sulfolobus shibatae is prototype of a novel family type II topoisomerases that share little sequence similarity with other enzymes, including bacterial and eukaryal archaeal gyrases. relaxes both negatively positively supercoiled in presence ATP has no supercoiling activity. The native enzyme heterotetramer composed two subunits, A B, apparent molecular masses 47 60 kDa, respectively. Here we report overexpression Escherichia coli...
The effects of ingestion poorly digestible carbohydrates on bacterial transformations cholic acid and β-muricholic were studied in rats fed increasing levels lactose, lactulose, amylomaize or potato starches. Each level was given for 3 weeks and, at the end each dietary treatment, bile faecal composition analysed a group six killed every 4 h during 24 to determine amounts fermented carbohydrate fermentation characteristics (caecal pH, volatile fatty acids (VFA) lactic concentrations)....
The similarities between essential molecular mechanisms in Archaea and Eukarya make it possible to discover, using comparative genomics, new fundamental conserved these two domains. We are studying a complex of proteins whose precise biological role biochemical function remain unknown. One them is universal protein known as Kae1 (kinase-asociated endopeptidase 1). second serine/threonine kinase corresponding the Bud32 Saccharomyces cerevisiae PRPK (p53-related kinase) humans. genes encoding...
Type II DNA topoisomerases are divided into two families, IIA and IIB. Types IIB enzymes share homologous B subunits encompassing the ATP-binding site, but have non-homologous A catalyzing cleavage. ubiquitous in Bacteria Eukarya, whereas members of family mostly present Archaea plants. Here, we report detection genes encoding type which fused a single polypeptide. These proteins encoded several bacterial genomes, plasmids one archaeal plasmid. They form monophyletic group that is very...
Type II DNA topoisomerases have been classified into two families, Topo IIA and IIB, based on structural mechanistic dissimilarities. is the target of many important antibiotics antitumoural drugs, most them being inactive IIB. The effects mode action inhibitors in vitro vivo extensively studied for last twenty-five years. In contrast, studies IIB were lacking. To document this field, we Hsp90 (radicicol geldanamycin), known to interact with ATP-binding site (the Bergerat fold), which also...
One of the major mechanisms driving evolution all organisms is genomic rearrangement. In hyperthermophilic Archaea order Thermococcales, large chromosomal inversions occur so frequently that even closely related genomes are difficult to align. Clearly not resulting from native homologous recombination machinery, causative agent these has remained elusive. We present a model in which catalyzed by integrase enzyme encoded family mobile genetic elements. characterized Thermococcus nautili...
Abstract The control of DNA topology by topoisomerases is essential for virtually all transactions in the cell. These enzymes, present every organism, exist as several non-homologous families. We previously identified a small group atypical type IIB topoisomerases, called Topo VIII, mainly encoded plasmids. Here, taking advantage rapid expansion sequence databases, we new putative VIII homologs. Our analyses confirm exclusivity corresponding genes to mobile genetic elements (MGE) and extend...
Maintaining an appropriate DNA topology with DNA-based processes (DNA replication, transcription and recombination) is crucial for all three domains of life. In bacteria, the homeostatic regulation controlling supercoiling relies on antagonistic activities two topoisomerases, TopoI gyrase. hyperthermophilic crenarchaea, presence such a regulatory system suggested as TopoVI reverse gyrase, catalyze activities. To test this hypothesis, we estimated compared number that gyrases, TopR1 TopR2, in...
Type IB DNA topoisomerases can eliminate torsional stresses produced during replication and transcription. These enzymes are found in all eukaryotes a short version is present some bacteria viruses. Among prokaryotes, the long eukaryotic only observed archaea of phylum Thaumarchaeota. However, activities roles these have remained an open question. Here, we demonstrate that available thaumarchaeal genomes contain topoisomerase gene defines monophyletic group closely related to enzymes. We...
The two DNA intercalators, actinomycin D and 2-methyl-9-hydroxy-ellipticine, the minor groove ligant DAPI inhibited growth of haloarchaeon Halobacterium sp. GRB bind to its plasmid pGRB-1. In contrast specific topoisomerase II inhibitors, they produced neither double-stranded breaks nor relaxation plasmidic DNA. intercalators positive supercoiling induced by novobiocin, suggesting that in haloarchaea is due transcription, as domain Bacteria. Plasmids from could thus be used prescreen for...