Schematic representation of translocation of the DNA-injection proteins and the assembly of the DNA-injection device in the host envelope.

<p>(A) The three DNA-injection proteins, gp12, gp11 and gp13, represented with an oval, triangle and trapezoid in blue, are packed in the phage particle. Note that the copy numbers of those proteins in the capsid and how they are arranged are not known. (B) upon attachment to the host cell, the DNA-injection proteins are translocated through the tail channel to the host cell envelope, where they assemble into an extended tube-like structure to allow delivery of phage DNA into the host cytoplasm. The arrangement of those proteins is not known and is drawn schematically. LPS, lipopolysaccharide; OM, outer membrane; PG, peptidoglycan; IM, inner membrane. The phage dsDNA is in green.