Docking poses of selected ligands docked into the HadAB
complex
with the HadA subunit represented in yellow, the HadB subunit represented
in lime green, and the ligand represented in cyan. (A) Compound 12, the oxadiazolone group occupies the catalytic site mimicking
the hydrolytic intermediate with its three H-bond acceptors to the
A-Q86 backbone amide, the B-G59 amide, and the catalytic water. (B)
Compound 11 forms all the interactions of acyl sulfonamide 9 but with the addition of a H-bond between the B-D36 aspartic
acid and the urea NH. (C) Compound 3 makes all the interactions
defined with 9 plus the addition of two new H-bonds between
the propylamine and A-Q86 and A-E81 at the binding site opening. (D)
Compound 15, lack of activity can be explained by the
5-ethyl substitution to the pyrazole core in a highly polar region
clashing with B-D36.