To further elucidate the critical role of the residue at position 169 in mediating water gating, we simulated the F169A mutant of the P450GcoA complex. Interestingly, we found changing the bulky Pheylanaline into a small residue alanine FA mutation opens the water gateway, and a persistent water channel is stretched from the surface to the heme-binding site(Figure ). This water chain might have further implications on enhanced native activity and promiscuity in the F169A variant as observed compared to the WT (Figure ).