Nucleotide sequence of bacteriophage f1 DNA

Abstract

The nucleotide sequence of the DNA of the filamentous coliphage f1 was determined. In agreement with earlier conclusions, the genome was found to comprise 6407 nucleotides, 1 less than that of the related phage fd. Phage f1 DNA differs from that of phage M13 by 52 nucleotide changes, which lead to 5 amino acid substitutions in the corresponding proteins of the 2 phages, and from phage fd DNA by 186 nucleotide changes (including the single-nucleotide deletion), which lead to 12 amino acid differences between the proteins of phages f1 and fd. Of the nucleotide changes in each case, > 1/2 are found in the sequence of 1786 nucleotides comprising gene IV and the major intergenic region between gene IV and gene II. The sequence of this intergenic region (nucleotides 5501 to 6005) of phage f1 differs from the sequence reported by others through the inclusion of additional single nucleotides in 8 positions and of a run of 13 nucleotides between positions 5885 and 5897, a point of uncertainty in the earlier published sequence. The differences between the sequence of bacteriophage f1 DNA now presented a complete sequence for the DNA previously published by others are discussed, and the f1 DNA sequence is compared with those of bacteriophages M13 and fd.