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. 13.1, p. 265

Table 13.1.4.1 

D. M. Blowa*‡

aBiophysics Group, Blackett Laboratory, Imperial College of Science, Technology & Medicine, London SW7 2BW, England
Correspondence e-mail: d.blow@ic.ac.uk

Table 13.1.4.1 | top | pdf |
Structure determination using noncrystallographic symmetry

Starting structural information Relationships within the same crystal (standard case) Relationships between different crystals (generalized case)
None (1) Subunit arrangement defined by relation between noncrystallographic and crystallographic symmetry. Resolution extended by noncrystallographic symmetry constraints (3)† Subunit arrangement defined by relation between noncrystallographic and crystallographic symmetry in at least one crystal. Cross-rotation and translation functions applied to other crystals. Resolution extended by noncrystallographic symmetry constraints
Poorly resolved structure, unsuitable for refinement (2) Electron density improved or resolution extended by noncrystallographic symmetry constraints (4)† Resolution extended by noncrystallographic symmetry constraints
Similar structure known   (5) Subunit orientation found by cross-rotation and translation functions. Phases derived from structural model and may be improved by noncrystallographic symmetry constraints
Part of unknown structure resembles a known structure   (6) Subunit orientation found by cross-rotation and translation functions. Phases derived from structural model and may be improved by noncrystallographic symmetry constraints
†Structure determinations of this kind have not been reported.