Dear Michael,
In sftools you can generate a set of FreeR flags on only a subset of the reflections. If you have a combined dataset (high and low relsoution), then select the high res refls, construct the FreeR set (unselected refls should not be changed) and write out. sftools READ MTZFILE SELECT RESOL < Res_Limit RFREE 0.05 SHELL SELECT ALL WRITE ANotherFile.mtz QUIT Only think to note is that the generated column will be called RFREE. Keep an eye on how many shells are used, might have to make them thicker. Finally to select high res refls use < not > . Adam _______________________________________________________________________ Good Morning, I am solving a structure with 6-fold NCS and consequently used sftools to select a 5% test set of reflections in thin resolution shells to monitor Rfree. I have reprocessed the same dataset to higher resolution to improve the quality of the electron density maps and now need to extend the test set. There appears to be no direct method in sftools of keeping the same test set while adding an additional set in the same proportion to higher resolution, also in thin shells. The only way I can see this might be done is to: 1. SELECT RESOL > to give the high resolution shell of reflections 2. Generate the test set from the high resolution shell using RFREE 0.05 SHELL. 3. SELECT RESOL > to produce a reflection file with the same resolution range as the old dataset. 4. READ [old dataset] COL RFREE. 5. SELECT COL RFREE=0. 6. SELECT ALL to include all reflections. 7. WRITE New_Dataset.mtz. The result should be a higher resolution dataset, with 5% test set of reflections in thin resolution shells, keeping the same test reflections as the old set. Will this work, or is there an alternative reliable procedure? Best wishes, Michael Michael Roberts Crysalin Limited Cherwell Innovation Centre 77 Heyford Park Upper Heyford Oxfordshire OX25 5HD Phone: 01869 238030
