Substrate docking using CDOCKER. Unique productive docking poses are shown as colored sticks, whereas unique unproductive docking poses are shown as black lines. The crystal structure of EPO-PTEAr is shown in panel a. Hydrogen atoms are not included since they are not observed in the crystal structure. In silico “docked” poses are also shown as follows: EPO-PTEAr (b), E-CVP-PTEAr (c), Z-CVP-PTEAr (d), E-CVP-PTEAr W131H/F132A (e), and Z-CVP-PTEAr W131H/F132A (f).