Hi Tassos, On Mon, Apr 12, 2010 at 04:10:57PM +0200, Anastassis Perrakis wrote: > As for Frank's argument, I fully agree low resolution cases are a > different ball game > (talking about ball games, I usually agree with Frank, he is much > bigger than me, and its healthier to agree with him, since I play > football with him one every two years at the Gordon).
I agree too ... especially since big Frank is sitting 2 metres away from me right now ;-) > A 4 A case, or anything below 3.0-3.2 A, warrants very careful > documentation of how maps were calculated, since its the quality of > the experimental maps rather than quality of the refinement that > will likely dominate model quality. In those cases I find an overall value always less meaningful than a more detailed break-down versus resolution (similar to SHELXC output - which would be my preferential stat to be reported for SHELXC/D/E solved structures). Often, a 3A dataset might only have meaningful heavy atom phases to 4-5A - and then the whole procedure for calculating maps, density modification, NCS averaging, automatic building etc becomes quite impoprtant. After all, a missing domain in those cases might just be due to very poor initial heavy atom phases that were misleading density modification procedures into flattening it away. So a good description of the procedure is even better (even if it is only in supplementary material) than just a number in some table 1. I like the phasing power statistics as three numbers: - what is the value in the lowest resolution range It often shows issues with overloads, poor beamstops etc - which can be a big problem later on. - at what resolution does it drop below 1.0 This gives me an idea what the initial, purely heavy-atom phased map will look like (and how one can improve the phases to the full resolution of the data). - overall value Not very useful, I find. > For higher resolution were nearly complete models are autobuilt from > the modified maps, i find the reporting of anything more than the > FOM (to satisfy my curiosity) a bit of a nuisance. Yes (although I still like the phasing power better - but this looks quite different for different phasing programs I guess). As long as it isn't the FOM after density modification which can be highly overestimated. Cheers Clemens -- *************************************************************** * Clemens Vonrhein, Ph.D. vonrhein AT GlobalPhasing DOT com * * Global Phasing Ltd. * Sheraton House, Castle Park * Cambridge CB3 0AX, UK *-------------------------------------------------------------- * BUSTER Development Group (http://www.globalphasing.com) ***************************************************************
