[ccp4bb] Multi crystal averaging : data on same scale before averaging?
Hi all Walking through multi xtal averaging with RAVE. I finally got a good mask and optimized NCS for my xtal forms. However, in the CRAVE manual I see this - the reflections in the input MTZ files *MUST* have been put on the same temperature factor scale prior to cross-crystal averaging (see the DATAMAN manual on how to do this) !!! Scale the separate datasets together? Wouldn't this just be a mess since the crystal should be non isomorphous to each other? Or does this say that within each dataset, all the data should be on the same scale (which would be if I used scala to scale) ? Am I interpreting this correctly? Thanks! F - Francis E. Reyes M.Sc. 215 UCB University of Colorado at Boulder
Re: [ccp4bb] Multi crystal averaging : data on same scale before averaging?
If I recall correctly DATAMAN does Wilson scaling in which the scale and B-factor are adjusted so the average reflection intensity in resolution bins are the same. I suspect it may not be required if all the data have been put on an approximately absolute scale by e.g. truncate (although that doesn't adjust the B-factor). If you do end up scaling your data in dataman, be sure to go back to the original data for refinement once you solve the structure, or your B-factors will not be right. eab Francis E Reyes wrote: Hi all Walking through multi xtal averaging with RAVE. I finally got a good mask and optimized NCS for my xtal forms. However, in the CRAVE manual I see this - the reflections in the input MTZ files *MUST* have been put on the same temperature factor scale prior to cross-crystal averaging (see the DATAMAN manual on how to do this) !!! Scale the separate datasets together? Wouldn't this just be a mess since the crystal should be non isomorphous to each other? Or does this say that within each dataset, all the data should be on the same scale (which would be if I used scala to scale) ? Am I interpreting this correctly? Thanks! F - Francis E. Reyes M.Sc. 215 UCB University of Colorado at Boulder
Re: [ccp4bb] Multi crystal averaging : data on same scale before averaging?
This is correct - see http://xray.bmc.uu.se/usf/dataman_man.html#S27 At the time I wrote this (1993...), I was a recovering NMRtist and The Other Gerard was doing a sabbatical in Uppsala and in fact in the office next to mine. He pointed out that I had to do this and also provided code. --The other other Gerard On Thu, 14 Jul 2011, Edward A. Berry wrote: If I recall correctly DATAMAN does Wilson scaling in which the scale and B-factor are adjusted so the average reflection intensity in resolution bins are the same. I suspect it may not be required if all the data have been put on an approximately absolute scale by e.g. truncate (although that doesn't adjust the B-factor). If you do end up scaling your data in dataman, be sure to go back to the original data for refinement once you solve the structure, or your B-factors will not be right. eab Francis E Reyes wrote: Hi all Walking through multi xtal averaging with RAVE. I finally got a good mask and optimized NCS for my xtal forms. However, in the CRAVE manual I see this - the reflections in the input MTZ files *MUST* have been put on the same temperature factor scale prior to cross-crystal averaging (see the DATAMAN manual on how to do this) !!! Scale the separate datasets together? Wouldn't this just be a mess since the crystal should be non isomorphous to each other? Or does this say that within each dataset, all the data should be on the same scale (which would be if I used scala to scale) ? Am I interpreting this correctly? Thanks! F - Francis E. Reyes M.Sc. 215 UCB University of Colorado at Boulder Best wishes, --Gerard ** Gerard J. Kleywegt http://xray.bmc.uu.se/gerard/ mailto:ger...@xray.bmc.uu.se ** The opinions in this message are fictional. Any similarity to actual opinions, living or dead, is purely coincidental. **
