Dear CCP4BB Users, I've recently solved the ~2.2 angstrom structure of a protein. In my electron density there are unusual monomer-monomer interfaces involving pairs of His and Cys residues (see https://ibb.co/wdWBcdk). Note the positive Fo-Fc density between the four side chains. As there is not adequate space for a water molecule or metal ion, perhaps the Cys residues are partially tied up disulfide bonds? However, the protein looks to be fully monomeric based on LC-MS measurements. Has anyone else observed crystal-driven formation of disulfide bridges?
Aside from this region, there is no extensive interface between momoners, and PDBePISA suggests a monomeric state. Thanks in advance for any advice! Best wishes, Chris ######################################################################## To unsubscribe from the CCP4BB list, click the following link: https://www.jiscmail.ac.uk/cgi-bin/webadmin?SUBED1=CCP4BB&A=1
