Data Item _refine.overall_SU_R_free


Item name
Category name
Attribute name
Required in PDB entries
Used in current PDB entries
Yes, in about 2.9 % of entries

Item Description

The overall standard uncertainty (estimated standard deviation) of the displacement parameters based on the free R value. The overall standard uncertainty (sigmaB) gives an idea of the uncertainty in the B values of averagely defined atoms (atoms with B values equal to the average B value). Na (sigmaB)2 = 0.65 ---------- (Rfree)2 (Dmin)2 C-2/3 (No-Np) Na = number of atoms included in refinement No = number of observations Np = number of parameters refined Rfree = conventional free crystallographic R value calculated using reflections not included in refinement Dmin = maximum resolution C = completeness of data Ref: Cruickshank, D. W. J. (1999). Acta Cryst. D55, 583-601. Murshudov, G. N. & Dodson, E. J. (1997). Simplified error estimation a la Cruickshank in macromolecular crystallography. CCP4 Newsletter on Protein Crystallography, No. 33, January 1997, pp. 31-39.

Data Type

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Data type detail
float item types are the subset of numbers that are the floating numbers.
Primitive data type code
Regular expression