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Refinement: Difference between revisions
→R-factor does not go down
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=== R-factor does not go down === | === R-factor does not go down === | ||
If this happens in the R-factor range of 30-40, here are a couple of possible reasons: | |||
* wrong spacegroup (usually the true symmetry is lower; see below) | |||
* [[twinning]] (this happens more often than you'd like, see [http://dx.doi.org/10.1107/S0907444905036759 A. A. Lebedev, A. A. Vagin and G. N. Murshudov (2006) Intensity statistics in twinned crystals with examples from the PDB. Acta Cryst. D62, 83-95]) | |||
* bad data - check the statistics of the data reduction program | |||
* model incomplete or wrong | |||
* other refinement options should be exploited, e.g. try TLS refinement | |||
=== help, my protein has high B-factors! === | === help, my protein has high B-factors! === | ||