[phenixbb] Difficult dataset and refinement--P422? I422?Twinning?
nechols at lbl.gov
Mon May 7 09:18:40 PDT 2012
On Mon, May 7, 2012 at 8:46 AM, Kelly Daughtry <kddaught at bu.edu> wrote:
> Looking at the P422 data, it look like you have pseudo translational symmetry.
> Did you try processing this data as I422?
> From the P422_xtriage.log:
> The full list of Patterson peaks is:
> x y z height p-value(height)
> ( 0.500, 0.500, 0.165 ) : 78.635 (6.634e-07)
> ( 0.000, 0.000, 0.330 ) : 56.292 (2.795e-05)
> ( 0.500, 0.500, 0.497 ) : 30.920 (1.207e-03)
One word of caution: an exceptionally high off-origin peak can mean
that the unit cell was measured too large, and you've integrated extra
reflections that are really non-existent. (I'm not sure what the
threshold for this is, but 80% seems pretty large.) Splitting and
various indexing artifacts can sometimes lead to this. I'd recommend
running labelit.index on the images and seeing what it thinks the
lattice should be.
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