Index

Macromolecular dictionary (mmCIF) version 2.0.09

_refine.overall_SU_R_Cruickshank_DPI

Definition:

   The overall standard uncertainty (estimated standard deviation)
   of the displacement parameters based on the crystallographic
   R value, expressed in a formalism known as the dispersion
   precision indicator (DPI).

   The overall standard uncertainty (sigma~B~) 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_value)^2 (D_min)^2 C^(-2/3)
                       (N_o-N_p)


   N_a      = number of atoms
   N_o      = number of reflections included in refinement
   N_p      = number of refined parameters
   R_value  = conventional crystallographic R value
   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