Dear Marin, The reason why you did not find a recent discussion or review about resolution metrics in X-ray crystallography is that this approach is nowadays obsolete. Having a metric (e.g. I/sigma, Rmerge, Rpim, CC1/2, CC*) can be useful and may give you a good estimate. It is also a fast way to make the decision. However, this is not an optimal estimate (now). Instead of insisting on a certain value of your metric, you should be validating trends in several metrics during the stepwise increase of your resolution - paired refinement.
Further reading: Original Paired Refinement paper - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3457925/ Program PAIREF for CCP4 users - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7340264/ Program PAIREF for PHENIX users - https://pubmed.ncbi.nlm.nih.gov/34196613/ There is more literature related to this issue. Unfortunately, I cannot comment on metrics for Cryo-EM. Best regards, Petr ________________________________ Od: CCP4 bulletin board <CCP4BB@JISCMAIL.AC.UK> za uživatele Marin van Heel <marin.vanh...@gmail.com> Odesláno: pondělí 7. října 2024 18:24 Komu: CCP4BB@JISCMAIL.AC.UK <CCP4BB@JISCMAIL.AC.UK> Předmět: [ccp4bb] Review: Linearity and Resolution in X-Ray Crystallography and Electron Microscopy E-maily z adresy marin.vanh...@gmail.com nedostáváte často. Přečtěte si, proč je to důležité<https://aka.ms/LearnAboutSenderIdentification> 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/
