Fig. 8

Structure of K223R/D317S mutant. a Comparison of the distance of residue 207–291 and residue 207–317 in wild-type bFMO (grey) and the K223R/D317S mutant (yellow), respectively. Residues are shown as gray sticks in wild-type bFMO. However, the residue 207, 291 and 317 are shown as purple, green and yellow sticks in the K223R/D317S mutant, respectively. b π–π interaction of Y207 (purple), indole (blue) and FAD (orange), and the π–π interaction between residues F165 and Y207 are shown in yellow dashed lines. The new hydrogen bond generated (green) between Y207 (purple) and Q318 (blue) to the indole (blue), respectively. The substrate tunnel shown in balls of wild-type bFMO (c) and the K223R/D317S mutant (d) was identified by CAVER 3.0