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 2.4 % 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

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

Advisory Boundary Conditions

Minimum Value Maximum Value
0 0.45