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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. 26.1, p. 751
Section 26.1.2.6.3. The absolute scale of the intensities
C. C. F. Blake,a‡ R. H. Fenn,a§ L. N. Johnson,a*¶ D. F. Koenig,a‡‡ G. A. Mair,a‡‡ A. C. T. North,a§§ J. W. H. Oldham,a¶¶ D. C. Phillips,a¶¶ R. J. Poljak,a‡‡‡ V. R. Sarmaa§§§ and C. A. Vernonb¶¶
a
Davy Faraday Research Laboratory, The Royal Institution, London W1X 4BS, England, and bDepartment of Chemistry, University College London, Gower Street, London WC1E 6BT, England |
An attempt was made to determine the absolute scale of the measured intensities by comparison with the intensities diffracted by anthracene, a small organic crystal of known structure. This method had worked well in a determination of the absolute scale for seal myoglobin (Scouloudi, 1960![[link]](/graphics/greenarr.gif)
), but it did not give a satisfactory result with lysozyme, mainly because of the difficulty of measuring the crystal volumes precisely enough. Accordingly, we used Wilson's (1942) method to provide an estimate of the absolute scale of the intensities, knowing very well that it does not give an accurate estimate for protein data, especially at low resolution. Nevertheless, this scale gave reasonable values for the occupancies of the heavy-atom sites.
References
Scouloudi, H. (1960). Structure of seal myoglobin in projection. Proc. R. Soc. London Ser. A, 258, 181.Google Scholar
Wilson, A. J. C. (1942). Determination of absolute from relative X-ray intensity data. Nature (London), 150, 151–152.Google Scholar
