An Information Portal to Biological Macromolecular Structures
PDB Home |		Dictionary Resources Home  |  Dictionary  |  Category Groups  |  Categories  |  Items  |  Data

Item _refine.overall_SU_R_free

Description

              The overall standard uncertainty (estimated standard deviation)
               of the displacement parameters based on the free R value.

               The overall standard uncertainty gives an idea of the
               uncertainty in the B values of averagely defined atoms
               (atoms with B values equal to the average B value).

                                    N_a
               (sigma_B)^2  = 0.65 ----- (R_free)^2 (D_min)^2 C^(-2/3)
                                    N_o

               N_a    = number of atoms
               N_o    = number of reflections included in refinement
               R_free = conventional free crystallographic R value calculated
                        using reflections not included in refinement
               D_min  = 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.
                   http://www.ccp4.ac.uk/newsletters/newsletter33/murshudov.html

Category

Mandatory Code

Data Type Code

Alias Names

 

© RCSB PDB