Introduction

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

Myoviridae

The Myoviridae is a family of bacteriophages. It has been divided into three subfamiles and a number of genera not yet assigned to a subfamily. There are at least 130 species in this family.-Virology:...

and the order Caudovirales

Caudovirales

The Caudovirales are an order of viruses also known as the tailed bacteriophages. Under the Baltimore classification scheme, the Caudovirales are group I viruses as they have double stranded DNA genomes, which can be anywhere from 18,000 base pairs to 500,000 base pairs in length...

, tailed viruses. Phage P2 has a double stranded DNA

DNA

Deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms . The DNA segments that carry this genetic information are called genes, but other DNA sequences have structural purposes, or are involved in...

 genome packaged in an icosahedral capsid with a diameter of 60 nm that is connected to a 135 nm long tail. 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.

Phage P2 is a representative member of the Myoviridae

There are three families in the order Caudovirales. The Siphoviridae have long flexible tails and constitute the majority of the tailed viruses. Myoviridae have long rigid tails and are fully characterized by the tail sheath that contracts upon phage attachment to bacterial host. The smallest family of tailed viruses are podoviruses (phage with short, leg-like tails).