Could it not just be classical radiation damage, that is known to love breaking SS bonds? If I understood correctly, single-particle cryo-EM inflicts much higher radiation doses than X-ray crystallography.
Best wishes, Gerard. -- On Wed, Dec 22, 2021 at 09:51:59AM +0000, Weiergräber, Oliver H. wrote: > Hmm, this may indeed be a disulfide bond, but the sulfur atoms do not seem to > occupy their density centroids. > They could be either _pushed_ apart by the refinement algorithm (which one > are you using?) or _pulled_ apart due to incorrect geometry in their > neighbourhood. > > Cheers > Oliver > > ================================================== > PD Dr. Oliver H. Weiergräber > Institut für Biologische Informationsprozesse > IBI-7: Strukturbiochemie > Tel.: +49 2461 61-2028 > Fax: +49 2461 61-9540 > ================================================== > > > ________________________________________ > From: CCP4 bulletin board [[email protected]] on behalf of Hochberg, > Georg [[email protected]] > Sent: 22 December 2021 10:06 > To: [email protected] > Subject: [ccp4bb] Strange cysteines > > Dear CCP4ers, > > > We have recently solved the structure of an enzyme by cryoEM, which has two > cysteines at its dimer interface, one in each monomer. The density around > these two cysteines is very odd (see picture). They are too far apart for a > disulphide bond, and there is nothing around these two cysteines that could > help coordinate a metal. This density is also not a result of symmetry > constraints in the density refinement either. We'd be very grateful for any > ideas. > > [cid:b92417da-97f2-4dc3-9b5c-92278a5318fd] > > > All the best and happy holidays, > > Georg Hochberg > > ________________________________ > > To unsubscribe from the CCP4BB list, click the following link: > https://www.jiscmail.ac.uk/cgi-bin/WA-JISC.exe?SUBED1=CCP4BB&A=1 > > > > ------------------------------------------------------------------------------------------------ > ------------------------------------------------------------------------------------------------ > Forschungszentrum Juelich GmbH > 52425 Juelich > Sitz der Gesellschaft: Juelich > Eingetragen im Handelsregister des Amtsgerichts Dueren Nr. HR B 3498 > Vorsitzender des Aufsichtsrats: MinDir Volker Rieke > Geschaeftsfuehrung: Prof. Dr.-Ing. Wolfgang Marquardt (Vorsitzender), > Karsten Beneke (stellv. Vorsitzender), Prof. Dr. Astrid Lambrecht, > Prof. Dr. Frauke Melchior > ------------------------------------------------------------------------------------------------ > ------------------------------------------------------------------------------------------------ > > > ######################################################################## > > 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/ ######################################################################## 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/
