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RE: [ccp4bb]: What is the CCP4 (refmac5) equivalent of an omit map?
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Perhaps solvent correction explains the difference between SHELX full aniso
and REFMAC TLS?
*******************************
Brent W. Segelke, Ph.D.
Lawrence Livermore National Lab
Livermore CA 94551
segelke1@llnl.gov
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-----Original Message-----
From: owner-ccp4bb@dl.ac.uk [mailto:owner-ccp4bb@dl.ac.uk]On Behalf Of
Ethan Merritt
Sent: Friday, January 25, 2002 1:18 PM
To: ccp4bb@dl.ac.uk
Subject: Re: [ccp4bb]: What is the CCP4 (refmac5) equivalent of an omit
map?
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On Friday 25 January 2002 11:16, Bernhard Rupp wrote:
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>
>
> In pdb are a number of structures, where refmac TLS was used, (converted
> to Uij s) and these structures show *extraordinarily* low freeR and R for
> the resolution. So I wonder to what degree your higher rfactors of the CNS
> model reflect just that, and also, to what degree those low TLS rfactors
> reflect a truely better model?
Furthermore I have just run into a case where the refmac TLS model
has lower R and Rfree than full anisotropic refinement. I found this
hard to believer, so I replicated the aniso refinement in shelx.
I'm still scratching my head over this one, but for the moment it seems
to be real. The resolution is distinctly margical (1.5A) for full aniso,
but I would have expected that if the refinement went bad I'd get a
lower R but higher Rfree; that's not what happens.
(watch for poster at the ACA meeting :-)
--
Ethan A Merritt merritt@u.washington.edu
Biomolecular Structure Center Box 357742
University of Washington, Seattle, WA 98195
phone: (206)543-1421
FAX: (206)685-7002