Dear bulletin board members, A referee came back with a question about the accuracy of refined group-occupancies. In the manuscript we describe 3 crystal structures with resolutions between 2.1 and 2.4 Å. In all three cases, the inhibitor has been fitted in two alternative conformations and the group occupancy of each conformation has been refined and the relative occupancies vary depending on the inhibitor.
The accuracy will depend on the amount of overlap between the inhibitor densities and the amount of unique density belonging only to one conformation and the amount of additional disorder of the inhibitors, since most of the interactions are non-specific hydrophobic interactions. Also partially occupied solvent molecules could lead to errors in the refined occupancies. My gut feeling is that the error will be somewhere between 20 and 30% or even higher, but I would be very happy if someone could come with a more scientific way, however crude, to get an estimate of this error. Best regards, Herman
