A DNA topoisomerase IB in Thaumarchaeota testifies for the presence of this enzyme in the last common ancestor of Archaea and Eucarya.
DNA topoisomerase IB (TopoIB) was thought for a long time to be a eukaryotic specific enzyme. A shorter version was then found in viruses and later on in several bacteria, but not in archaea. Here, we show that a eukaryotic-like TopoIB is present in the recently sequenced genomes of two archaea of the newly proposed phylum Thaumarchaeota. Phylogenetic analyses suggest that a TopoIB was present in the last common ancestor of Archaea and Eucarya. This finding indicates that the last common ancestor of Archaea and Eucarya may have harboured a DNA genome.
Brochier-Armanet
Céline
C
Laboratoire de Chimie Bactérienne, Université de Provence, Aix-Marseille I, CNRS UPR9043, IFR88, Marseille, France. celine.brochier@ibsm.cnrs-mrs.fr
Gribaldo
Simonetta
S
Forterre
Patrick
P
D001105:Archaea / Q000201:enzymology*; D001419:Bacteria / Q000201:enzymology; D004264:DNA Topoisomerases, Type I / Q000737:chemistry / Q000235:genetics*; D005057:Eukaryotic Cells / Q000201:enzymology*; D016013:Likelihood Functions; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D014780:Viruses / Q000201:enzymology
D004264:DNA Topoisomerases, Type I