The complete nucleotide sequence of the left very early region of Escherichia coli bacteriophage PRD1 coding for the terminal protein and the DNA polymerase.

DNA molecules replicating in a linear form have been found in certain viruses and plasmids of both prokaryotic and eukaryotic origin. Characteristic of this type of molecules are the proteins covalently linked to their 5' ends and inverted terminal nucleotide sequences. The molecules replicate via a protein-priming mechanism, where participants include terminal protein and a specific polymerase. We report here the nucleotide sequence of the left very early region of Escherichia coli bacteriophage PRD1. This region codes for the terminal protein and the phage DNA polymerase. The predicted amino acid sequence of the terminal protein does not share homology with those of other known terminal proteins. The PRD1 DNA polymerase shows four regions of extensive homology to that of Bacillus subtilis phage phi 29. One of these conserved regions is also found in several animal virus DNA polymerases.