Re: [ccp4bb]: REFMAC5 maximum likelihood refinement

["Eleanor J. Dodson" <ccp4@ysbl.york.ac.uk>]

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Wolfram Tempel wrote:
> 
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> Hi all,
> under which circumstances would maximum likelihood target refinement in
> REFMAC5 produce a dramatic INCREASE in R (from 0.187 to 0.208) and Rfree
> (from 0.232 to 0.257) with 1.8A data? This was not accompanied by
> improved geometry (reduced RMSs). Any idea where I should start looking
> for the underlying problem?
> Thank you.
> Wolfram Tempel
> U. of Georgia


 That is hard question to answer..
Is there any indication something has "blown up"? eg there are serious
clashes between rebuilt residues? You will need to scan the log file to
see if this has been monitored.

Or sometimes one accidently alters the resolution range or the number of
reflections..

Or a different scaling algorithm could weight low resolution data
differently, and give a change in overall R factor which  is mostly ue
to changes at low resln..

Send more details if you like

Eleanor Dodson