Hi, On Wed, Jul 31, 2019 at 07:11:10PM +0100, Weston Lane wrote: > Thanks for the response. I did look at the multiplicity of the > datasets in their table and while I suppose 6.9x redundancy is sort > of high for P2 spacegroup it's actually lower than some of the other > datasets (presumably non-Eiger) in the table with good overall > Rmerge (e.g. a C2 dataset with 10x redundancy and an Rmerge of > 0.064).
Maybe a multiplicity of 6.9 is not especially low for monoclinic: 5LP9 for example (Pilatus data) has 6.3 for 360 degree of data (and Rmerge of 0.045 to 0.864A when re-processing). Yes, that is more data than traditionally collected for monoclinic (180 degree), but still far away from some real high multiplicity approaches. So this looks much more like a crysal issue to me: maybe there are some really poor image ranges (that then give an overall Rmerge of 0.256). The overall I/sigI is also rather low (7), and if you look at http://staraniso.globalphasing.org/cgi-bin/PDBpeep.cgi?ID=6hr5 you can see that even in the lowest shell the I/sigI is only about 15 - so maybe a seriously underexposed crystal? Low dose, high-multiplicity is very good - but only if one still takes advantage of the dose budget a crystal provides. It doesn't help underexposing a crystal for only 360 degree if it could give still good data for 720, 1080 or 1440 degree. The great opportunity of low dose, high multiplicity is that it allows one to see radiation damage happening and then selecting a subset of images from the start that are still complete with a nice multiplicity. At least that is how I approach this with Pilatus/Eiger detectors (or other photon counting ones) ... Cheers Clemens PS: it would be great to have those images deposited (at proteindiffraction.org, sbgrid,org or zenodo.org et al) :-) -- *-------------------------------------------------------------- * Clemens Vonrhein, Ph.D. vonrhein AT GlobalPhasing DOT com * Global Phasing Ltd., Sheraton House, Castle Park * Cambridge CB3 0AX, UK www.globalphasing.com *-------------------------------------------------------------- ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
