Hi Doeke, I've encountered this issue quite often.
The information should ideally be stored in the _diffrn.details flag, but that's not always the case. Typically, the first array of reflections corresponds to X-ray data and the second to neutron data, but this isn't always reliable. There are cases where reflections are missing, or X-ray reflections are mislabeled as neutron reflections and vice versa. For example, in the case of 5A93, the second array of reflections is named data_r5a93Neutronsf, making it clear. However, in cases like 7UCR, it's not as obvious. One way to determine which data array corresponds to which experiment is by computing R-work using both X-ray and neutron scattering factors for each data set. The incorrect set of scattering factors will result in significantly higher R factors. While not ideal, this method is often the only option when no other information is available. If you need to extract data arrays from a combined sf.cif file, you can easily do so using gemmi: gemmi cif2mtz -B 2 file-sf.cif file.mtz Here, -B 2 specifies the second block in the file. Hope helps. Lucrezia Lucrezia Catapano, PhD (she/her) Postdoctoral Scientist, Murshudov Group MRC Laboratory of Molecular Biology Francis Crick Avenue, Cambridge CB2 0QH, UK. lucre...@mrc-lmb.cam.ac.uk > On 24 Feb 2025, at 16:17, Hekstra, Doeke Romke <doeke_heks...@harvard.edu> > wrote: > > CAUTION: This email originated from outside of the LMB: > .-owner-ccp...@jiscmail.ac.uk <mailto:owner-ccp...@jiscmail.ac.uk>-. > Do not click links or open attachments unless you recognize the sender and > know the content is safe. > If you think this is a phishing email, please forward it to > phish...@mrc-lmb.cam.ac.uk <mailto:phish...@mrc-lmb.cam.ac.uk> > > -- > > Hi, > > Maybe a dumb question. When looking at some PDB entries based on joint X-ray > and neutron refinement (e.g., 5A93, 7UCR), we’re confused about what is > stored in the PDB-provided sfCIF files and/or how to tell the neutron > diffraction from X-ray diffraction data. > > For example, for 5A93 I’d infer the sfCIF contains neutron data based on the > resolution limit, but I don’t recognize any flag telling me more. > > Thank you, > Doeke > > ===== > > Doeke Hekstra > Associate Professor of Molecular & Cellular Biology, and of Applied Physics > (SEAS), > Director of Undergraduate Studies, Chemical and Physical Biology > Center for Systems Biology, Harvard University > 52 Oxford Street, NW311 > Cambridge, MA 02138 > Office: 617-496-4740 > Admin: 617-495-5651 (Lin Song) > > > > > > > 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/
