Table 1. PDB entries rejected from analysis.

The main reasons for refinement failures were (i) new ligands not present in the CCP4 monomer library, (ii) amplitudes of structure factors not present in the PDB entry (those with only intensities deposited were excluded from our analysis) and (iii) no experimental data were available. In the final stage, if the highest resolution of the data was higher than 1.5 Å or lower than 3 Å then the entry was removed from further analysis.

No. of remaining entries	Rejected	Reason for rejection
89862	1749	Zero B value
88113	1914	Viruses
86299	229	Zero occupancy
86070	261	Space-group incompatibility
85009	19965	Failed refinement
65844	744	High R factor
65100	18148	Outside resolution 1.5–3 Å
46952	—	—