Figure 7.

Crystal structures of the type III secretion ATPases, FliI, and EscN. (A) Model of the ATPase domain of the FliI hexamer (blue and yellow) superimposed onto the ATPase domain (blue-green) and (orange) of F1-ATPase (Imada et al. 2007). (B) Top-view of the EscN hexamer model; position of the ATP shown in a van-der-Waals representation in gold (Zarivach et al. 2007). (C) Crystal structure of the flagellar type III ATPase FliI (Δ1–18) missing the first 18 residues (PDB 2DPY). (D) Crystal structure of the C-terminal domain, residues 103–446 of the injectisome ATPase EscN (PDB 2OBL). (A, reprinted, with permission, from Imada et al. 2007 [© National Academy of Sciences]; B, reprinted, with permission, from Zarivach et al. 2007 [Nature Publishing Group]; C, Protein database accession number 2DPY, based on Imada et al. 2007; D, Protein database accession number 2OBL, based on Zarivach et al. 2007.)