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. 19.5, p. 445   | 1 | 2 |

Section 19.5.3.5. Diffracted intensities: noncrystalline fibres

R. Chandrasekarana* and G. Stubbsb

aWhistler Center for Carbohydrate Research, Purdue University, West Lafayette, IN 47907, USA, and  bDepartment of Molecular Biology, Vanderbilt University, Nashville, TN 37235, USA
Correspondence e-mail:  chandra@purdue.edu

19.5.3.5. Diffracted intensities: noncrystalline fibres

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The intensity in the diffraction pattern of a noncrystalline fibre is the cylindrical average of the square of the Fourier transform (Franklin & Klug, 1955[link]): [\eqalignno{ I (R, l) &= \langle|\hbox{{\bf F}}(R, \psi, l/c)|^{2}\rangle_{\psi} &\cr &= \textstyle\sum\limits_{n}\displaystyle \hbox{{\bf G}}_{n, \, l} (R) {\hbox{{\bf G}}^{*}_{n, \, l}} (R) &\cr &= \textstyle\sum\limits_{n}\displaystyle |\hbox{{\bf G}}_{n, \, l} (R)|^{2}. &(19.5.3.7)\cr}] The intensity varies continuously as a function of R along each layer line (Fig. 19.5.2.1a[link]).

References

First citation Franklin, R. E. & Klug, A. (1955). The splitting of layer lines in X-ray fibre diagrams of helical structures: application to tobacco mosaic virus. Acta Cryst. 8, 777–780.Google Scholar








































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