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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. 18.3, p. 391
Section 18.3.2.7. Effects of hydrogen atoms in parameterization
a
Pharmaceutical Research, Roche Diagnostics GmbH, Max Planck Institut für Biochemie, 82152 Martinsried, Germany, and bMax-Planck-Institut für Biochemie, 82152 Martinsried, Germany |
While many CSD fragments include hydrogen-atom positions, their accuracy is necessarily the most limited. Evaluation of CSD statistics without hydrogens and the subsequent addition of parameters to refine hydrogens adds an additional artifactual coupling between parameters involving non-hydrogen atoms as well. This artifactual coupling might theoretically be of some concern, but is a second-order effect and presumably introduces effects smaller than the artifactual coupling between non-hydrogen parameters, for example.
