A surface representation of TAFI structure. The activation peptide is shown in blue, the catalytic domain is in green, and the dynamic “flap” residues are depicted in orange. Critical residues are depicted: residues involved in the interactions between the dynamic flap (Y341) and the activation peptide (V35 and L39), the cryptic thrombin cleavage site at Arg302, the N-linked glycans (cyan), and the catalytic zinc ion (magenta sphere). An artistic “blurring” rendition of the “flap” is utilized to depict its dynamic nature.