Re: [ccp4bb] twinning or not?

[Phil Evans]

You can get apparent twinning if neighbouring spots are overlapped in any direction, and that may be worse with a home source with larger beam divergence. In that case a weak reflection may be corrupted by a neighbouring strong reflection, leading to intensity statistics characteristic of twinning Phil Sent from my iPad On 25 Mar 2024, at 19:24, Thomas, Leonard M. <lmtho...@ou.edu> wrote:  CAUTION: This email originated from outside of the LMB: .-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 -- Hello, I have run into a very odd situation.  Upon collection and data processing on a crystal on my home source all pointers seemed to show twinning.  Was not surprised since previous crystals under different but related conditions have showed significant twinning though the cell dimensions were different but not the resulting apparent space group.   Now the odd thing, I sent the crystal to the synchrotron figuring I might be able to get some data that might help figure out what is going on.  Upon processing of the synchrotron data, SSRL 9-2, magically no twining was detected.  A couple of other crystals of the same compound though not from the same exact condition showed the twinning.  I processed the data using HKL, which I primarily on my home source data and XDS with similar results.   In summary, the exact same crystal shows twinning on Cu home source and no twinning at all at the synchrotron. Any ideas would be welcomed. Len Leonard Thomas, Ph.D. Biomolecular Structure Core, Director Oklahoma COBRE in Structural Biology Price Family Foundation Institute of Structural Biology University of Oklahoma Department of Chemistry and Biochemistry 101 Stephenson Parkway Norman, OK 73019-5251 Office: (405)325-1126 lmtho...@ou.edu http://www.ou.edu/structuralbiology/cobre-core-facilities/mcl 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