A side point, worth considering depending on your x-ray source: many years ago we threw out several crystals in a row for having split spots before we finally realized that the BEAM was split, not the crystals. Oops.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Phoebe A. Rice Dept. of Biochem & Mol. Biol. and Committee on Microbiology https://voices.uchicago.edu/phoebericelab/ From: CCP4 bulletin board <[email protected]> on behalf of Eleanor Dodson <[email protected]> Reply-To: Eleanor Dodson <[email protected]> Date: Wednesday, March 17, 2021 at 5:20 AM To: "[email protected]" <[email protected]> Subject: Re: [ccp4bb] Can twinning be seen in the diffraction pattern? Yes Ana, I agree although some non-merihedrals where the accident of cell dimensions mean many spots can overlap but not quite exactly can seem a bit smeary and "multiple. Meridral twins do not usually look multiple - they are usually only revealed by the 2nd moment and other stats.. Eleanor On Wed, 17 Mar 2021 at 10:13, Ana Luísa Moreira de Carvalho <[email protected]<mailto:[email protected]>> wrote: Just a short note on this: I often see colleagues using the word “twinning" when referring to a crystal that is actually multiple (not single). I think much confusion arises from this. For me, a twin crystal is the one that looks single under the microscope and only intensity statistics reveal that the diffraction comes from more than one crystal. If a crystal looks multiple, i do not call it a twin. Am i being too meticulous on this? Thanks! On 16 Mar 2021, at 13:31, Eleanor Dodson <[email protected]<mailto:[email protected]>> wrote: You usually detect twinning most reliably from the intensity statistics - CCP4I2 and Xtriage report those.. Eleanor On Tue, 16 Mar 2021 at 07:31, Marina Gárdonyi <[email protected]<mailto:[email protected]>> wrote: Dear all, thanks to all who helped me solving the question. You sent me a lot of comments and information I have not taken into account. After reading all the answers, I have come to the conclusion that the spots that are very close to each other come from the long cell axis (57-57-160) and that twinning can probably not be seen in my case. I should have mentioned that the diffraction images came from an in-house x-ray machine, recorded with a 0.5 degree rotation range. Thank you all again! Kind regards, Marina -- Marina Gárdonyi PhD Student, Research Group Professor Dr. Klebe Department of Pharmaceutical Chemistry Philipps-University Marburg Marbacher Weg 6, 35032 Marburg, Germany Phone: +49 6421 28 21392 E-Mail: [email protected]<mailto:[email protected]> http://www.agklebe.de/ ######################################################################## 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<http://www.jiscmail.ac.uk/CCP4BB>, a mailing list hosted by www.jiscmail.ac.uk<http://www.jiscmail.ac.uk/>, terms & conditions are available at https://www.jiscmail.ac.uk/policyandsecurity/ ________________________________ 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 ________________________________ 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/
