Hi Mark,
After refinement with TLS how should we switch to
refinement with aniso individual ADPs. i know
that both cannot be done simultaneously at
present.
Just turn off the TLS refinement option. Since input PDB file will
contain atoms with ANISOU records they will be refined as anisotropic
automatically. Alternatively, you can specify which atoms to refine as
isotropic or anisotropic.
Following up on Mark's question: we also have a
set of structures of resolution 1.5 to 1.24 Å
resolution that are good candidates for
anisotropic refinement, but selecting the subset
of residues to refine is not easy (for us).
We can exclude loops and terminii with high
isotropic ADPs, but even for the remaining well
ordered parts of the protein we are left with
surface residues with well ordered main chain but
less well ordered side chains (e.g, Lys and Glu),
which need to be refined isotropically. Also, we
would like to exclude residues with alternative
conformations from anisotropic refinment.
At present its a fair amount of work to build up
a residue selection to satisfy these requirements.
The goal is to make refinement completely automated where you hit
Enter
and get refined structure. What you describe above is one of the items
in to-do list for further automation.
Also, I do not think you need to refine as isotropic the atoms with
large B-factors. Yes, ac should probably be refined as isotropic. This
is something to systematically study (as part of the overall planned
automation).
For the moment, I would just remove from anisotropic refinement some
very obvious parts that should be refined as isotropic and I'm almost
sure it will be enough in most of the cases.
Pavel.
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