Sequence comparison among DNA fragments from different sources with pac site function for the packaging apparatus of Salmonella phage P22.

Two different DNA fragments, deriving from the P22-related bacteriophage LP7 and from the right IS element of transposon Tn10, have been identified which were recognized by the P22-packaging apparatus as pac-like signals. Their nucleotide sequences were compared with the known sequence of P22 gene 3 which contains the P22 pac site. Both sequences show similarity to a particular segment of P22 DNA close to a region identified earlier as part of pac.