Data Item _refine_ls_shell.pdbx_fsc_free
Browse:
General 
- Item name
- _refine_ls_shell.pdbx_fsc_free
- Category name
- refine_ls_shell
- Attribute name
- pdbx_fsc_free
- Required in PDB entries
- no
- Used in current PDB entries
- Yes, in about 0.6 % of entries
Item Description
Fourier Shell Correlation (FSC) between model and
observed structure factors for reflections not included in refinement.
FSC is a measure of the agreement between observed
and calculated structure factors as complex numbers.
(sum(|Fo| |Fc| fom cos(phic-phio)))
FSCfree = --------------------------------------
(sum(|Fo|2) (sum(|Fc|2)))1/2
|Fo| = amplitude of observed structure factor
|Fc| = amplitude of calculated structure factor
phio = phase of observed structure factor
phic = phase of calculated structure factor
fom = figure of merit of the experimental phases.
Summation is carried over all free reflections in the resolution shell.
Ref: Rosenthal P.B., Henderson R.
"Optimal determination of particle orientation, absolute hand,
and contrast loss in single-particle electron cryomicroscopy.
Journal of Molecular Biology. 2003;333(4):721-745, equation (A6).
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]+)?