Fig. 5

The catalytic domain of FXIIIa is presented as a potential binding site for EA showing the covalent bond between the α,β-unsaturated ketone the catalytic Cys324. Other potential important interactions are H-bonds between the ketone group of EA and the NH-groups of the side chains of Gln313 and Trp279. The carboxylic acid also potentially establishes H-bond with the side chain of the Asn371 residue. The 2-Cl substituent also forms a halogen-H interaction with the side chain of the Asn371 residue. EA is represented as stick and balls. Atoms are represented with the following colors: carbon = cyan, chlorine = green, oxygen = red, nitrogen = blue, and sulfur = yellow. The protein backbone cartoon is represented in green-yellowish color