FIGURE 5.

Scheme of the proposed initial steps of T7 infection. The main components in this process (nozzle, gp12; fiber, gp17; and LPS) are labeled. Synchronized interaction of the six fibers with the rough LPS assists correct orientation of the tail and triggers opening of the valve, liberating DNA. As a result, the nozzle changes its conformation, opening the channel to allow translocation and subsequent assembly of the core in the bacterial envelope; this generates the conduit for safe DNA delivery into the cytoplasm, after which the core complex is degraded.