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International
Tables for Crystallography Volume F Crystallography of biological macromolecules Edited by M. G. Rossmann and E. Arnold © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. F. ch. 25.2, p. 719
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25.2.4.5.9. Generalization of noncrystallographic symmetry operators to include shifts in the average B factor (1998)
It is rather common in crystals containing multiple copies of a molecule in the asymmetric unit for one or more molecules to have a higher B factor than the others. If the transformation that generates each copy of the molecule consists only of a rotation and translation of the positions of the atoms, the difference in B factors cannot be modelled. The transformations used in TNT now consist of a rotation, translation, a B-factor shift and an occupancy shift.
