[phenixbb] Twinning Refinement

[Peter Zwart]

didn't look properly.

Nat is correct: the data processing is seriously flawed.
Reduce in P1 and see how that look.s

P


2010/3/25 Nathaniel Echols <NEchols at lbl.gov>:
> On Mar 25, 2010, at 10:13 PM, Joseph Brock wrote:
>> Shell Lower Upper Average      Average     Norm. Linear Square
>>  limit    Angstrom       I   error   stat. Chi**2  R-fac  R-fac
>>       50.00   4.09  7648.3  1498.7 182.7 1.030  0.376  0.424
>>   All reflections   1588.3   269.2    41.9  1.350  0.400  0.444
>
> Aside from what Peter said: aren't these R-sym values are far too high for the symmetry (or indexing) to be correct?  Or is this allowed when twinning is present?  If Scalepack is throwing away that much data, this is also telling you that something else is wrong.  I'd start back at the indexing step and re-process in P1, then follow the rest of Peter's suggestions starting from step 2.2 (MR).  Also, I'd recomment trying labelit.index (included in any Phenix distribution after 1.5) on the raw images, because it may notice something that the conventional indexing programs miss.
>
> As a general rule, you can't always assume that the symmetry will always be the same from crystal to crystal - identical proteins may form completely different crystal lattices depending on crystallization condition or ligand binding or freak chance.
>
> -Nat
>
> --------------------
> Nathaniel Echols
> Lawrence Berkeley Lab
> 510-486-5136
> NEchols at lbl.gov
>
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P.H. Zwart
Beamline Scientist
Berkeley Center for Structural Biology
Lawrence Berkeley National Laboratories
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