Fig. 5: Position of FlhBC in the complete T3SS.

a Placement of FliPQR–FlhB in a tomographic reconstruction of the Salmonella SPI-1 vT3SS (EMD-8544)47. FliPQR is shown in grey, FlhBTM in green, two possible positions of FlhBC (PDB: 3b0z)15 in yellow and light blue, and the density corresponding to the FlhA homologue is highlighted in blue. b Network of salt bridges formed by conserved charged residues in FlhB.