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R-factors: Difference between revisions
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→what kinds of problems exist with these indicators?: include table from Murshudov paper
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* Sets of reflections used for calculating R<sub>free</sub> should be maintained throughout a project. This is nicely discussed at http://www.bmsc.washington.edu/people/merritt/xplor/rfree_example.html . Note that none of the programs mentioned for selecting thin shells will allow you to extend the set of shells to higher resolution if you want to preserve your existing R-free set. | * Sets of reflections used for calculating R<sub>free</sub> should be maintained throughout a project. This is nicely discussed at http://www.bmsc.washington.edu/people/merritt/xplor/rfree_example.html . Note that none of the programs mentioned for selecting thin shells will allow you to extend the set of shells to higher resolution if you want to preserve your existing R-free set. | ||
* R-values and twinning: [http://www.science.az/acm/V10,%20N2,%202011,%20pdf/250-261.pdf Garib N. Murshudov (2011) "Some properties of crystallographic reliability index - Rfactor: effect of twinning" Appl. Comput. Math., V.10, N.2, 2011, pp.250-261] | * R-values and twinning: [http://www.science.az/acm/V10,%20N2,%202011,%20pdf/250-261.pdf Garib N. Murshudov (2011) "Some properties of crystallographic reliability index - Rfactor: effect of twinning" Appl. Comput. Math., V.10, N.2, 2011, pp.250-261]. From the paper, the R-value table for random models is: | ||
twinning twinning not | |||
modelled modelled | |||
twin 0.41 0.49 | |||
normal 0.52 0.58 | |||
* R-values and [[pseudo-translation]]: if you have pseudotranslation you should be aware that even if you solve the structure by molecular replacement, starting R factors could be 70-80%. | * R-values and [[pseudo-translation]]: if you have pseudotranslation you should be aware that even if you solve the structure by molecular replacement, starting R factors could be 70-80%. | ||