Data Item _refine.pdbx_average_fsc_free


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Average Fourier Shell Correlation (avgFSC) between model and observed structure factors for reflections not included in refinement. The average FSC is a measure of the agreement between observed and calculated structure factors. sum(Ni FSCfree-i) avgFSCfree = --------------------- sum(Ni) Ni = the number of free reflections in the resolution shell i FSCfree-i = FSC for free reflections in the i-th resolution shell calculated as: (sum(|Fo| |Fc| fom cos(phic-phio))) FSCfree-i = ------------------------------------------- (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 of FSCfree-i is carried over all free reflections in the resolution shell. Summation of avgFSCfree is carried over all resolution shells. 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).

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