Primary structure of the DNA terminal protein of bacteriophage PRD1

The genome of a lipid-containing phage, PRD1, is replicated by a proteinpriming mechanism. We have determined the nucleotide sequence of the PRD1 gene 8 which specifies the terminal protein, the protein primer for DNA synthesis. The coding region is 780 base pairs long and encodes for 259 amino acids (29,326 daltons). The predicted amino acid sequence of the PRD1 terminal protein reveals no substantial hamlogy with that of any known texminal protein. However, hydropathy profiles of the FRDl , ø29, and Nf terminal proteins are remarkably similar, suggesting a common evolutionary origin. A prticular tyrosine residue is predicted to be covalently linked to the 5′ end of the PRD1 DNA. The initiation codon ATG of gene 8 is preceded by the identifiable ribosome binding site, and putative promoter sequences. There are unique palindromic sequences between the ribosome binding site and "-10" region.