Inhibitor-binding and mutations reduce dynamic-flap mobility. Panels A through C depict σA-weighted 2Fo-Fc electron density maps at 1.0 σ contour level for residues 296-350 in molecule B of TAFI (A), TAFI-GEMSA (B), and TAFI-IIYQ (C). Panels D through F express TAFI mobility as the average B-factor per residue for the 3 molecules in the asymmetric unit of the crystal. In wild-type TAFI (D), mobility of residues 296-350 is more than the average for the entire molecule, in particular for molecule B. In TAFI-GEMSA (E), B-factors in this region are reduced. In TAFI-IIYQ (F), B-factors in the flap are similar to the average for the molecule. Molecule A is shown in blue, molecule B in red, and molecule C in green. Gray area denotes residues of the dynamic flap.