[phenixbb] R-factor expectations when translational pseudo symmetry is present

[Tanner, John J.]

Dear PhenixBB,

We have a crystal form that xtriage flags as having strong translational pseudo symmetry (Patterson peak 57% the height of the origin peak, p-value = 3E-5).

The space group is P21212. We can solve the structure with MR and refine to R=0.233 and R-free =0.276 at 2.25 Angstrom resolution. The maps look very good, but do not suggest major additional modeling that could be done to improve the structure and lower the R-factors. I know that one expects the R-factors from refinement to be higher when TPS is present, but my question is how high is too high?  Has anyone done a study that shows the expectations for R-factors when TPS is present?

Thanks,

Jack

John J. Tanner
Interim Chair, Department of Biochemistry
Professor of Biochemistry and Chemistry
Department of Biochemistry
University of Missouri-Columbia
117 Schweitzer Hall
503 S College Avenue
Columbia, MO 65211
Phone: 573-884-1280
Fax: 573-882-5635
Email: tannerjj at missouri.edu<mailto:tannerjj at missouri.edu>
http://faculty.missouri.edu/~tannerjj/tannergroup/tanner.html
Lab: Schlundt Annex rooms 3,6,9, 203B, 203C
Office: Schlundt Annex 203A

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