A HETERODIMERIC DNA-POLYMERASE - EVIDENCE THAT MEMBERS OF EURYARCHAEOTA POSSESS A DISTINCT DNA-POLYMERASE

We describe here a DNA polymerase family highly conserved in Euryarcha eota, a subdomain of Archaea. The DNA polymerase is composed of two pr oteins, DP1 and DP2. Sequence analysis showed that considerable simila rity exists between DP1 and the second subunit of eukaryotic DNA polym erase delta, a protein essential for the propagation of Eukarya, and t hat DP2 has conserved motifs found in proteins with nucleotide-polymer izing activity. These results, together with our previous biochemical analyses of one of the members, DNA polymerase II (DP1 + DP2) from Pyr ococcus furiosus, implicate the DNA polymerases of this family in the DNA replication process of Euryarchaeota. The discovery of this DNA-po lymerase family, aside from providing an opportunity to enhance our kn owledge of the evolution of DNA polymerases, is a significant step tow ard the complete understanding of DNA replication across the three dom ains of life.