Heidi Schubert wrote:
>
> Hi
>
> I would like to convert a map into SFs to use for molecular replacement.
> Read on if you think you can help.
>
> I have a 3.7A MAD data set and a few 30% similar homology models for
> crystal in i222 space group. The combination of the two pieces of
> information generated solvent flattened phases which reflect unique
> information and have a FOM of 0.65. Workable, but certainly any model I
> build is inherently poor.
>
> I have new data for the same protein (2 mols in the ASU now) in C2 space
> group with data to 2.1A. The poor models (original models and an
> attempt at a "better" built model from the 3.7A phases) do not work as
> molecular replacement solutions in Phaser or MolRep. It would be better
> if I could use the i222-3.7A map for the molecular replacement into the
> new space group.
>
> PHASER manual says "This density has been cut out and converted to
> structure factors in a large cell"
> So, how do I do that?
>
Randy J. Read wrote:
> The procedure of cutting out electron density, putting it into a large
> unit cell, and backtransforming to get structure factors can be tricky
> (as you've discovered), so we put some instructions on our webpage:
>
> http://www-structmed.cimr.cam.ac.uk/phaser/density_as_model.html
>
> The last time I tried that it worked, but let me know if you run into
> any problems with your case.
>
> Randy Read
HTH
Ed
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