Figure 4. Visualization of Φ29 adsorption.

A, B) Two tomographic slices show phage particles interacting with the cell wall at an angle. C) Averaged structure of adsorbed Φ29 and its interaction with the cell wall at an angle similar to that shown in A and B. D) Surface rendering of the average map. Crystal structures were manually docked into the cryo-ET densities for the gp8.5 head fibers (Xiang and Rossmann, 2011), gp12* appendages (Xiang et al., 2009) and gp13 tail tip protein (Xiang et al., 2008). The appendage in yellow is in the extended conformation. E) Model of the interaction between a “down” appendage based on tomographic observations with a juxtaposed schematic diagram of the Gram-positive cell wall. F) Model of the tail knob position from C and D with manual docking of the crystal structure of the distal tip protein gp13; a cell wall schematic is juxtaposed. In surface renderings and crystal models, head fibers are shown in light blue, the capsid in darker blue, appendages in oranges and yellow, and the tail is shown as a gradient from blue to green, terminating with the tail knob.