Hi James,

That is not exactly a lot of info to decide the best weight. The optimal weight is (very loosely) resolution dependent. At normal resolutions the optimal matrix weight is usually well below 1.0. Start at 0.3 and try a few weights to see what works best for your data. To close the R-free gap you can also try to optimize other refinement parameters such as NCS restraints, B-factor model (and restraint weight). Jelly body restraints sometimes work really well to keep the R-free gap sensible, especially at low resolution.

Cheers,

Robbie

From: CCP4 bulletin board [mailto:[log in to unmask]] On Behalf Of james09 pruza
Sent: Tuesday, November 08, 2011 06:40
To: [log in to unmask]
Subject: [ccp4bb] weight matrix and R-FreeR gap optimization

Dear ccp4bbers,

I wonder if someone can help me defining proper weight matrix term in Refmac5 to lower the R-FreeR gap. The log file indicates weight matrix of 1.98 with a gap of 7. Thanks for suggestions in advance.

James