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. 11.5, p. 241   | 1 | 2 |

Section 11.5.8. Conclusions

C. G. van Beek,a R. Bolotovskya§ and M. G. Rossmanna*

aDepartment of Biological Sciences, Purdue University, West Lafayette, IN 47907-1392, USA
Correspondence e-mail:  mgr@indiana.bio.purdue.edu

11.5.8. Conclusions

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The generalized HRS method allows scaling and averaging of X-ray diffraction data collected with an oscillation camera while simultaneously using full and partial reflections. The procedure is as useful for thin slices of reciprocal space as it is for thicker slices.

The results of data processing with the two different algorithms indicate that method 1[link], based on adding partial reflections, may fail to scale data sets with gaps in the rotation range or with low redundancy. The values of the scale factors obtained with both methods are similar, except for cases where there are gaps in the rotation range or dramatic changes in the true scale factors between consecutive frames. In these cases, method 1[link] produces a physically wrong result. The algorithm used by method 1[link] is probably similar to that used by SCALEPACK (Otwinowski & Minor, 1997[link]).

Method 2[link] is more stable and versatile than method 1[link], and allows the scaling of data sets with incompletely measured reflections and low redundancy. The major drawback of method 2[link] is that errors in the crystal orientation matrix and mosaicity, as well as inadequacies of the theoretical model for reflection partiality, contribute to errors in the scaled intensities. Therefore, post refinement is needed for method 2[link] to perform at its best.

References

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