[ccp4bb] Valid to stop Refmac after TLS refinement?

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CCP4bb <-- 2007 <-- March 2007 <-- 28 March 2007

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From: artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU
Date: 2007-03-28

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From: barry {- dot -} hardy {- at -} TELE2 {- dot -} CH barry {- dot -} hardy {- at -} TELE2 {- dot -} CH
Date: 2007-03-28

Subject: Valid to stop Refmac after TLS refinement?
From: "NM Burton, Biochemistry" Nick {- dot -} Burton {- at -} BRISTOL {- dot -} AC {- dot -} UK
Date: 2007-03-28

Hello,

I've refined a structure with CNS to Rwork/free=0.226/0.273. I switched to
Refmac5.2 to take advantage of TLS refinement and set up a run with 10
cycles of TLS refinement (groups as suggested by the TLSMD server) followed
by 10 cycles of restrained co-ordinate refinement. After the TLS cycles
the model was improved (Rwork/free=0.222/0.241), however during co-ordinate
refinement Rfree refined up (final Rwork/free=0.197/0.264). My
understanding would be that the TLS refinement is modelling the ADPs most
accurately, but that Refmac's co-ordinate refinement is over-fitting
slightly. Would this seem correct? And if so, is it valid to run Refmac
with no cycles of co-ordinate refinement and take the resulting model as
the final structure?

Thanks very much,

Nick

----------------------
NM Burton, Biochemistry
Nick.Burton@bristol.ac.uk

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CCP4bb <-- 2007 <-- March 2007 <-- 28 March 2007

Previous message:
Subject: Re: phasing power ofatoms
From: artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU artis {- at -} CHEMISTRY {- dot -} MONTANA {- dot -} EDU
Date: 2007-03-28