Fig. 4.
Baseplate completion and sheath formation. a Interaction between gp6 and gp27, a hub protein. b Formation of the first and second annuli of gp18.The C-terminal structure of gp18 which resembles gp25 is indicated by red. c Interactions between gp18 and the baseplate proteins gp6, gp53 and gp25. Tube polymerization starts with (gp48)6(gp54)6 binding. Then after gp25 binds, tail sheath association or polymerization will start. C-terminal structure of gp18 which resembles gp25 is shown in red