Fig. 4

Docking analysis of the bFMO–indole complex, which shows the location of theα4 helix (purple) and the loop 220–223 (blue). a π–π stacking interactions of Y207–indole–FAD are indicated by yellow dashed lines, and residues in blue sticks. The F165 is also involved in π–π stacking interaction with indole. Green dotted line indicates hydrogen bond between N73 and FAD. b Indirubin titer of the mutants of bFMO in vivo. Statistical analysis was performed using the Student’s t test (one-tailed; two-sample unequal variance; *p < 0.05, **p < 0.01, ***p < 0.001). All data represent the mean of n = 3 biologically independent samples and error bars show the standard deviation