Index

Macromolecular dictionary (mmCIF) version 2.0.09

_refine.overall_SU_R_free

Definition:

   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

Type: float

Mandatory item: no

Category: refine