Figure 7.

Model for T4P-mediated uptake of CTXφ. A, CTXφ binds via its tip-associated minor coat protein pIII to the minor pilin TcpB trimer at the tip of a growing V. cholerae TCP filament. B–D, random incorporation of TcpB monomer at the base of the growing pilus stalls pilus assembly (B), triggering retraction (C), which draws the phage into the periplasm as if it were an extension of the pilus (D and E). TcpB is shown as a trimer, with its pilin domain colored blue and its effector domain colored green. IM, inner membrane; OM, outer membrane.