Described at: http://www.ccp4.ac.uk/dist/html/refmac5/keywords/xray-principal.html#scal
Simple scaling doesn't take into account the bulk solvent at all, whereas Babinet is a simple fix. A more sophisticated treatment of bulk solvent is given by the SOLVENT keyword: http://www.ccp4.ac.uk/dist/html/refmac5/keywords/xray-principal.html#solv which generates a solvent mask and calculates a contribution to Fcalc from that. In the GUI, this is the "Calculate the contribution from the solvent region" button in the Scaling folder. By default this is on, and scaling type is SIMPLE. In principle, Babinet scaling and solvent mask calculation are alternative treatments of bulk solvent. There was a time however when it seemed to be better to use both (presumably not as bad as it sounds because scale factors will adjust for double counting). I think that's no longer true, but its always possible to "suck it and see" ... The bottom line: if you've run with defaults, it's probably ok. With high solvent content, you certainly need to model the solvent one way or the other! Cheers Martyn -----Original Message----- From: CCP4 bulletin board on behalf of Alexandra Deaconescu Sent: Thu 11/19/2009 3:55 AM To: CCP4BB@JISCMAIL.AC.UK Subject: [ccp4bb] refmac Hi everyone: Can someone enlighten me as to the difference between "simple" scaling and "Babinet scaling" in Refmac? It seems to me that Babinet scaling is more similar to what is employed in CNS for bulk solvent correction (Ksolv, Bsolv search). Is that correct? Would you recommend the Babinet method for high solvent content/ low resolution structures? Thanks a lot, Alex -- Scanned by iCritical.
