Hi all,
I have an interesting problem case at the moment.
We have crystallized the same 2-domain protein in two different,
i.e. non-isomorphous, crystal forms.
There is a decent homologous structure for one domain
(about 40% of the total), but no known homologous structure for
the larger second domain. Phaser easily places the probe structure
in both unit cells, but recovering the remaining 60% of the structure
from that starting point is problematic.
In both cells there is only a single copy of the protein per a.s.u.,
Resolution is on the order of 2.6A, and the solvent content is
relatively low. So no help from NCS or solvent flattening for
either structure by itself.
Yes, we can start searching for derivatives or SeMet data, but
meanwhile I am looking for advice on the current generation of tools
available for cross-crystal density averaging.
Are there any that tie in to auto-tracing in Arp/wArp or resolve?
Is there any chance of eventually doing joint refining of both structures
simultaneously?
--
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742
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