Escherichia virus T4 is a species of bacteriophage that infects Escherichia coli bacteria.12 It is a double-stranded DNA virus in the subfamily Tevenvirinae from the family Myoviridae.2 T4 assembly is divided into three independent pathways: the head, the tail, and the long tail fibers. The prolate head encapsidates a 172 kbp concatemeric dsDNA genome. T4 is classified as a member in the Myoviridae family of the Caudovirales order because it has a contractile tail.0 The injection machinery of T4 is responsible for recognizing and puncturing the bacterial host and transferring the viral genome into the host during infection. Although the atomic structure of T4 is largely understood, the dynamics of its injection machinery remain unknown. A system-level model of the entire bacteriophage T4 interacting with a host cell has been developed to expose the energetics, forces, and dynamical pathway associated with the injection process.1