Data Item _phasing_MIR_der.R_cullis_anomalous

General

Item name
_phasing_MIR_der.R_cullis_anomalous
Category name
phasing_MIR_der
Attribute name
R_cullis_anomalous
Required in PDB entries
no
Used in current PDB entries
Yes, in about 0.001 % of entries

Item Description

Residual factor Rcullis,ano for anomalous reflections for this derivative. The Cullis R factor was originally defined only for centric reflections. It is, however, also a useful statistical measure for anomalous reflections, which is how it is used in this data item. This is tabulated for acentric terms. A value less than 1.0 means there is some contribution to the phasing from the anomalous data. sum |Fph+obsFph-obs - Fh+calc - Fh-calc| Rcullis,ano = ------------------------------------------------ sum|Fph+obs - Fph-obs| Fph+obs = the observed positive Friedel structure-factor amplitude for the derivative Fph-obs = the observed negative Friedel structure-factor amplitude for the derivative Fh+calc = the calculated positive Friedel structure-factor amplitude from the heavy-atom model Fh-calc = the calculated negative Friedel structure-factor amplitude from the heavy-atom model sum is taken over the specified reflections Ref: Cullis, A. F., Muirhead, H., Perutz, M. F., Rossmann, M. G. & North, A. C. T. (1961). Proc. R. Soc. London Ser. A, 265, 15-38.

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]+)?

Allowed Boundary Conditions

Minimum Value Maximum Value
0.0

+∞