Data Item _pdbx_refine_component.correlation_main_chain

General

Item name
_pdbx_refine_component.correlation_main_chain
Category name
pdbx_refine_component
Attribute name
correlation_main_chain
Required in PDB entries
no
Used in currrent PDB entries
No

Item Description

Correlation coefficient of electron density for each residue or ligand, side chain, main chain The density correlation coefficient is calculated for each component from atomic densities of (2Fobs-Fcalc) map - "Robs" and the model map (Fcalc) - "Rcalc" : D_corr = <Robs><Rcalc>/sqrt(<Robs**2><Rcalc**2>) where <Robs> is the mean of "observed" densities of atoms of the component (backbone or side chain). <Rcalc> is the mean of "calculated" densities of component atoms. The value of density for some atom from map R(x) is: sum_i ( R(xi) * Ratom(xi - xa) ) Dens = ---------------------------------- sum_i ( Ratom(xi - xa) ) where Ratom(x) is atomic electron density for the x-th grid point. xa - vector of the centre of atom. xi - vector of the i-th point of grid. Sum is taken over all grid points which have distance from the center of the atom less than the Radius_limit. For all atoms Radius_limit = 2.5 A. Ref: Vaguine, A.A., Richelle, J. & Wodak, S.J. (1999). Acta Cryst. D55,199-205

Data Type

Data type code
float
Data type detail
float item types are the subset of numbers that are the floating numbers.
Primitive data type code
numb
Regular expression
-?(([0-9]+)[.]?|([0-9]*[.][0-9]+))([(][0-9]+[)])?([eE][+-]?[0-9]+)?