[ccp4bb] modelling radiation damage of Asp/Glu (occ vs. B factor)

[John Pak]

Hi all, I was hoping to receive some guidance on the following subject.
I'm refining a structure using REFMAC that shows all the symptoms of  
radiation damage.  Namely partially broken disulphide bonds and  
decarboxylated Asp/Glu residues.  I have an idea of how to handle the  
partially broken disulphides.  I was wondering how people model  
decarboxylated Asp/Glu residues.  Do you adjust the occupancy of the  
carboxylic acid moiety until the negative Fo-Fc density goes away, or  
do you losen the side-chain B factor restraint in REFMAC to something  
higher, like 30 A^2.  I don't know which is more appropriate.

Thanks.