Genomic structure of the Salmonella enterica serovar Typhimurium DT 64 bacteriophage ST64T: evidence for modular genetic architecture

The complete sequence of the double-stranded DNA genome of a serotype-converting temperate bacteriophage, ST64T, was determined. The 40,679-bp genomic sequence of ST64T has an overall GC content of 47.5% and was reminiscent of a number of lambdoid phages, in particular, P22. Inferred proteins of ST64T which exhibited a high degree of sequence similarity to P22 proteins (>90%) included the functional serotype conversion cassette, integrase, excisionase, Abc1, Abc2, early antitermination (gp24), NinD, NinH, NinZ, packaging (gp3 and gp2), head (with the exception of gp26, gp7, gp20, and gp16), and tail proteins. The putative immunity genes were highly related to those of Salmonella enterica serotype Typhimurium phage L, whereas the lysis genes were almost identical to those of S. enterica serovar Typhimurium PS3.