The structure of chain A of AcmB in complex with the reaction product (androst-1,4-diene- or dihydrotestosterone (DHT), with the use of the Kabsch algorithm . The protonation states of the titrable amino acids were determined with propKa3.1 for pH 6.5. The missing molecular mechanics (MM) charges for ketosteroids were obtained with Gaussian16 35 at the B3LYP/6-31G(d,p) level of theory . The FAD parameters were taken from RESP ESP charge DataBase (R.E.DD.B) . The charge of the protein, ketosteroid, and FAD combined was +1, which was neutralized by the addition of one Cl -ion. The models were soaked with TIP3P