Dear Eleanor, I did not check the pdb file you mentioned, but I have had a case like that. The protein formed a complex of 8 large and 8 small subunits with internal 422 symmetry. There was a disulfide link across the internal twofolds and in one of the crystal forms we got, this internal twofold came on top of a crystallographic twofold. At the time, I did not know about these sophisticated SSBOND records (if they existed at the time), so I assigned a very small van der Waals radius to the SGs to solve the repulsion problem.
So, if you have a dimer with an existing disulfide link across the twofold axis, this twofold axis may become a crystallographic twofold and there is no need for the disulfide bond to form afterwards. Best regards, Herman Von: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] Im Auftrag von Eleanor Dodson Gesendet: Mittwoch, 1. Februar 2017 16:18 An: CCP4BB@JISCMAIL.AC.UK Betreff: [ccp4bb] intermolecular dissulphides Does anyone know of examples of these? I have found one - 2WQW with these SSBOND records 2WQW SSBOND 1 CYS A 206 CYS A 227 1555 6556 2.07 SSBOND 2 CYS B 206 CYS B 227 1555 5556 2.15 We seem to have one but it would have to form after crystalisation? Eleanor
