Hi Eric, Since you are asking your question on the CCP4 bulletin board, I will give a CCP4 answer. Take your model refined to 2.7A and through it into PDB_REDO with the full 2.3A dataset. It will automatically do paired refinement and pick a resolution cut-off in REFMAC. No mucking about with all sorts of programs. One difference with the K&D paper is that the resolution steps are such that they contain the same number of reflections.
HTH, Robbie Sent with my Windows Phone ________________________________ Van: Eric Karg<mailto:0000052044071b36-dmarc-requ...@jiscmail.ac.uk> Verzonden: 2-7-2015 01:28 Aan: CCP4BB@JISCMAIL.AC.UK<mailto:CCP4BB@JISCMAIL.AC.UK> Onderwerp: [ccp4bb] paired refinement Hi all, I have a dataset processed in XDS to 2.3 A (based on CC1/2). I'm trying to do "paired refinement" to determine the optimal resolution cutoff. Here is what I get at different resolutions set in Phenix: Final Rfree/Rwork: 2.7—> 0.2498/0.2027 2.6—> 0.2519/0.2009 2.5—> 0.2567/0.2025 2.4 —> 0.2481/0.2042 2.3 —> 0.2493/0.2075 The geometry of all output structures are similar. 1. What is the high resolution cutoff based on these data? I know that Rfree/Rwork at different resolution should not be compared, but is there a simple way to do the test as described in the K&D 2012 Science paper using Phenix GUI? 2. For refining a structure at a lower resolution (lower than the initial dataset), do I simply set the resolution limit in the refinement or I need to reprocess the data starting from the images? Do I need to do anything with Rfree flags? Based on the discussions on this forum I know I should deposit the highest resolution dataset but my question is about the mtz file which will be used for refinement. Thank you very much for your help!
