Hi, Browsing through the recent discussion on EM data resolution cutoff it occurred to me that the X-ray diffraction community isn’t that unanimous either.
My stand: When the default resolution cutoff provided with the data processing software in electron density map calculation and refinement delivers quality maps noisier than expected and/or too high R-factors I start adjusting the resolution cutoff by lowering the resolution and trying alternative space group. Hence, I allow the data processing programs to suggest where to draw the line (be it CC1/2, I/sigI, R merge, R sym, R p.i.m. and R r.i.m, …) , unless there are problems. Doing so, I came into a dispute with a referee who shaped his request: "It is well accepted that the criteria for resolution cutoff should consider both I/SigI and Rmerge for the outer most shell. For data sets collected at synchrotron sources, the criteria of I/SigI > 5 and Rmerge <50% can be taken as a good practical reference.” So where do we stand? Which are the most objective criteria for resolution cutoff to be used in diffraction data processing? Which number of shells to use when calculating the statistics? Do we have a consensus? best wishes, dusan turk Dr. Dusan Turk, Prof. Head of Structural Biology Group http://stef.ijs.si/ Head of Centre for Protein and Structure Production Centre of excellence for Integrated Approaches in Chemistry and Biology of Proteins, Scientific Director http://www.cipkebip.org/ e-mail: dusan.t...@ijs.si phone: +386 1 477 3857 Dept. of Biochem.& Mol.& Struct. Biology fax: +386 1 477 3984 Jozef Stefan Institute Jamova 39, 1 000 Ljubljana,Slovenia Skype: dusan.turk (voice over internet: www.skype.com ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
