I think it is not really the detector, but the strategy. If you decrease exposure time by a factor of ten and make up for it by 10 x higher redundancy, then obviously R-merge, which is a measure of accuracy of the individual frames, is going to suffer. Chi^2 statistics can distinguish this from a real problem with the data reduction. And I guess the capabilities of the Eiger detectors tend to encourage high-redundancy, low dose/frame strategies? (No 6HR5 is not mine).
On 07/31/2019 12:49 PM, Weston Lane wrote:
I was looking at the following structure in the PDB: https://urldefense.proofpoint.com/v2/url?u=http-3A__www.rcsb.org_structure_6HR5&d=DwIFaQ&c=ogn2iPkgF7TkVSicOVBfKg&r=cFgyH4s-peZ6Pfyh0zB379rxK2XG5oHu7VblrALfYPA&m=2NZPl2iBIAyGDtZO7h2CtE0DqQqnPQb_sHo94gbPGAo&s=yti3AVLhix2oCPzcWyto9IuLqgqbU7KWxfTgQ0hleBY&e= I noticed that the R/Rfree stats were pretty high for 2.9A resolution so I followed up by looking for the "Table 1" statistics in the journal article. Link to article: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.nature.com_articles_s41589-2D019-2D0311-2D9&d=DwIFaQ&c=ogn2iPkgF7TkVSicOVBfKg&r=cFgyH4s-peZ6Pfyh0zB379rxK2XG5oHu7VblrALfYPA&m=2NZPl2iBIAyGDtZO7h2CtE0DqQqnPQb_sHo94gbPGAo&s=qkFehKN3fqEKQJMkmTiecg_OMR82xFIi_5h8yCl-AZs&e= Table is located in the supplemental materials "Table 9". From the processing statistics it's clear that the diffraction from that crystal wasn't great but I don't want to get hung up on the processing or the validity of the structure. What struck me what this little explanation the authors included to explain the outlier statistics in the table: "Crystal of P36_S1_25 was collected on an Eiger detector, so Rmerge data are not relevant." We all know that Rmerge isn't a great metric for data quality but I've never heard that it's detector-dependent. This doesn't make sense to me. If it's actually true can someone explain, please? Thanks! Wes ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://urldefense.proofpoint.com/v2/url?u=https-3A__www.jiscmail.ac.uk_cgi-2Dbin_webadmin-3FSUBED1-3DCCP4BB-26A-3D1&d=DwIFaQ&c=ogn2iPkgF7TkVSicOVBfKg&r=cFgyH4s-peZ6Pfyh0zB379rxK2XG5oHu7VblrALfYPA&m=2NZPl2iBIAyGDtZO7h2CtE0DqQqnPQb_sHo94gbPGAo&s=0LkQSlw7CAGx_joUG4cjhh2tKY5Rn2ZhprEv8SpHqes&e=
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