Hi all, I'm refining a couple of structures of the same protein (well, point mutants) and I am consistently seeing large (6sig) negative difference map peaks within some cavities within my protein, present in both the datasets. As far as I understand, this is because the bulk solvent scaling parameters are either incorrect, or being incorrectly applied. I have tried a few things like applying the "Refine solvent mask (slow)" options, all to no avail. Resolution is 2.2Å and 2.5Å. Experimental phasing, Xtriage reports no abnormalities in the data. Is there anything that I am missing? Do I need to worry about this? Regards, Dave ============================ David C. Briggs PhD Father, Structural Biologist and Sceptic ============================ University of Manchester E-mail: [email protected] ============================ Webs : http://flavors.me/xtaldave Twitter: @xtaldave Skype: DocDCB ============================