FIGURE 2.
Comparison of cryo-EM structures of gp19.1-gp211–552 in its closed and open conformation with SPP1 tail maps before and after DNA ejection. SPP1 tail and tail cap maps are in yellow and the tail tip map is in blue. The cryo-EM structures of gp19.1-gp211–552 in its open and closed states are in blue mesh. A, closed state versus phage tail structure before DNA ejection. Gp19.1 fits well in the upper part of tail cap, which contacts the tail tube, whereas gp211–552 fits well in the lower part of the tail cap. B, open state versus tail phage structure after DNA ejection. The opening of the tail cap is equivalent to that observed in the open conformation map of gp19.1-gp211–552 complex. Common characteristic features with the open conformation map of gp19.1-gp2l1–552 complex can be identified. Hence, the six protruding domains of gp19.1 can be observed in the upper part of the tail cap map, whereas the lower part presents domains that superimpose well with Bd and Sd domains of the open conformation map of the gp19.1-gp211–552 complex.