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Nat Struct Biol. 1997 Apr;4(4):269-75.

Improved R-factors for diffraction data analysis in macromolecular crystallography.

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Universität Konstanz, Fakultät für Biologie, Germany.

Erratum in

  • Nat Struct Biol 1997 Jul;4(7):592.


The quantity Rsym (also called Rmerge) is almost universally used for describing X-ray diffraction data quality. Here, we prove that Rsym is seriously flawed, because it has an implicit dependence on the redundance of the data. A corrected R-factor, Rmeas, is introduced as the equivalent robust indicator of data consistency. In addition, we introduce Rmrgd an R-factor that reflects the gain in accuracy upon averaging of equivalent reflections, as a useful indicator of the quality of reduced data. These new data quality indicators better reveal the benefits of highly redundant data and should stimulate improvements in data quality through increased merging of data from multiple crystals.

[Indexed for MEDLINE]

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