Enterobacteria phage P2

Bacteriophage P2 is a temperate phage that infects E. coli. It is a tailed virus with a contractile sheath and is thus classified in the family Myoviridae and the order Caudovirales. This class of viruses includes many P2-like phages as well as the satellite phage P4.

Bacteriophage P2 was first isolated by G. Bertani from the Lisbonne and Carrère strain of E. coli in 1951. Since that time, a large number of P2-like prophages (e.g. 186, HP1, HK239, and WΦ) have been isolated that shared characters such as host range, serological relatedness and inability to recombine with phage λ, and they seemed to be quite common in E. coli populations as about 30% of the strains in the E. coli reference collection (ECOR) contain P2-like prophages . Of these P2-like prophages is P2 best characterized. The P2 phage was found to be able to multiply in many strains of E. coli, as well as in strains of many other species including Serratia, Klebsiella pneumoniae, and Yersinia sp, which suggested that it played an important role in horizontal gene transfer in bacterial evolution.

Phage P2 has a double stranded DNA genome packaged in an icosahedral capsid with a diameter of 60 nanometers that is connected to a 135 nanometer long tail. Presence of phage P4 can cause P2 to form smaller capsids. The tail ends in a baseplate which is the control hub for phage infectivity. The baseplate includes 6 tail fibers which initially bind to receptors on the bacterial cell wall and a tail spike protein that subsequently binds irreversibly to other receptors on the cell wall.

The genome of bacteriophage P2 is 33,592 bp of double-stranded, linear DNA with cohesive ends (accession number AF063097). The 42 genes in the genome can be divided in three main categories: (i) genes required for lytic growth, (ii) genes involved in establishing and maintaining lysogeny (such as int and C), and (iii) the nonessential genes (including old, tin, and Z/fun). Furthermore, a number of open reading frames (ORFs) is found in P2 genome, which may encode functional proteins.

...
Wikipedia