Fig. 1.

Homology between SpoIIIAH and the YscJ/FliF protein family. HHpred alignment of SpoIIIAH and the YscJ/FliF family. (A) Identical (black boxes) and similar (gray boxes) amino acids are highlighted. Predicted secondary structure is indicated above the alignment. Cartoon representations of the type III secretion system (B), flagellar basal body (C), and SpoIIIAH channel model (D). YscJ, FliF, and SpoIIIAH are labeled and colored green. The extracellular space (ES), cell wall (CW), periplasm (P), and cytoplasm (C) of gram-negative bacteria, and mother cell (MC), intermembrane space (IMS), and forespore (FS) of bacterial endospores are indicated.