International
Tables for
Crystallography
Volume F
Crystallography of biological macromolecules
Edited by M. G. Rossmann and E. Arnold

International Tables for Crystallography (2006). Vol. F. ch. 18.5, p. 408   | 1 | 2 |

Section 18.5.4.3. Comments on restrained refinement

D. W. J. Cruickshanka*

aChemistry Department, UMIST, Manchester M60 1QD, England
Correspondence e-mail: dwj_cruickshank@email.msn.com

18.5.4.3. Comments on restrained refinement

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Geometric restraint dictionaries typically use bond-length weights based on [\sigma_{\rm geom}(l)] of around 0.02 or 0.03 Å. Tables 18.5.7.1[link] [link]–18.5.7.3[link] show that even 1.5 Å studies have diffraction-only errors [\sigma_{\rm diff}(x, B_{\rm avg})] of 0.08 Å and upwards. Only for resolutions of 1.0 Å or so are the diffraction-only errors comparable with the dictionary weights. Of course, the dictionary offers no values for many of the configurational parameters of the protein structure, including the centroid and molecular orientation.








































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