Figure 2.

Inter-protomer Interactions of the TssB1C1 Heterodimer within the Sheath

(A) TssB1C1 heterodimers from the same protofilament are colored (TssB1 in pink and TssC1 in purple) in the context of the whole sheath (gray; left) and highlighted to show one 360° helical turn (right).

(B) Schematic representation of a TssB1C1 heterodimer color coded as described above. (i) Handshake interaction responsible for tube formation. (ii) β sheet essential for maintaining the structural integrity of the TssB1C1 heterodimer. (iii) Tri-helical vertical packing interaction along stiles stabilized by hydrophobic interactions.

See also Figure S2.