I think this is taken care of: The CC1/2 and the CC1/2* are appropriate metrics for the resolution limit. They are all spit out by newer data processing software. The CC1/2 is directly comparable to the FSC. Many people use CC1/2 = 1/e as the resolution limit. In many cases of data the CC1/2 = 1/e is equivalent to I/sigI of 1, which is used sometimes as a metric for the resolution limit (some use I/sigI = 2), and in more cases the CC1/2 corresponds to Rmerge in the range of 40%. For serial crystallography, the R-split goes through the roof at CC1/2 = 1/e, so the CC1/2 is the better metric.
Best Marius Marius Schmidt, Dr. rer. Nat. (habil.) Professor University of Wisconsin-Milwaukee Kenwood Interdisciplinary Research Complex Physics Department, Room 3087 3135 North Maryland Avenue Milwaukee, Wi 53211 phone (office): 1-414-229-4338 phone (lab): 414-229-3946 email: smar...@uwm.edu https://uwm.edu/physics/people/schmidt-marius/ https://sites.uwm.edu/smarius/ https://www.bioxfel.org/ Nature News and Views: https://www.nature.com/articles/d41586-023-00504-4 ________________________________ From: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> on behalf of Marin van Heel <marin.vanh...@gmail.com> Sent: Monday, October 7, 2024 11:24 AM To: CCP4BB@JISCMAIL.AC.UK <CCP4BB@JISCMAIL.AC.UK> Subject: [ccp4bb] Review: Linearity and Resolution in X-Ray Crystallography and Electron Microscopy Dear All, Sayan Bhakta and I have recently posted the preprint of a review on resolution and linearity which will appear in a book to be launched on the 16th of October 2024. ( https://doi.org/10.1201/9781003326106 ). It is the first Cryo-EM review that I have been involved in for 25 years. In our preparation, I was quite amazed about what other authors wrote (or did not write) in their many reviews on these matters. For example, I missed any serious discussion about resolution metrics in X-ray crystallography, which technique is fundamentally non-linear. Linearity is a prerequisite for defining the resolution of any instrument. The iterative refinements applied in X-ray crystallography (and sometimes Cryo-EM) makes that all Phase-residuals and R-factors or fixed threshold values cannot be used to compare the results of independently conducted experiments. What is an obvious consequence of the lack of universality of such metrics like phase-residuals and R-factors, is that they cannot be used outside of the immediate context in which they were defined, like X-ray crystallography or structural biology. In contrast, the Fourier-Ring-Correlation (FRC); Fourier-Shell-Correlation (FSC) and their recent successors: the Fourier-Ring-Information (FRI) and the Fourier-Shell-Information (FSI), plus their integrated versions, are universal metrics that are applicable to all fields of science where 2D and 3D data are dealt with! https://doi.org/10.31219/osf.io/5empt Have fun reading it! Marin ________________________________ To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 This message was issued to members of www.jiscmail.ac.uk/CCP4BB, a mailing list hosted by www.jiscmail.ac.uk, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/
