International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

International Tables for Crystallography (2006). Vol. B. ch. 4.5, pp. 466-467   | 1 | 2 |

Section 4.5.2.1. Introduction

R. P. Millanea*

4.5.2.1. Introduction

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X-ray fibre diffraction analysis is a collection of crystallographic techniques that are used to determine molecular and crystal structures of molecules, or molecular assemblies, that form specimens (often fibres) in which the molecules, assemblies or crystallites are approximately parallel but not otherwise ordered (Arnott, 1980[link]; French & Gardner, 1980[link]; Hall, 1984[link]; Vibert, 1987[link]; Millane, 1988[link]; Atkins, 1989[link]; Stubbs, 1999[link]). These are usually long, slender molecules and they are often inherently flexible, which usually precludes the formation of regular three-dimensional crystals suitable for conventional crystallographic analysis. X-ray fibre diffraction therefore provides a route for structure determination for certain kinds of specimens that cannot be crystallized. Although it may be possible to crystallize small fragments or subunits of these molecules, and determine the crystal structures of these, X-ray fibre diffraction provides a means for studying the intact, and often the biologically or functionally active, system. Fibre diffraction has played an important role in the determination of biopolymers such as polynucleotides, polysaccharides (both linear and branched), polypeptides and a wide variety of synthetic polymers (such as polyesters), as well as larger assemblies including rod-like helical viruses, bacteriophages, microtubules and muscle fibres (Arnott, 1980[link]; Arnott & Mitra, 1984[link]; Millane, 1990c[link]; Squire & Vibert, 1987[link]).

Specimens appropriate for fibre diffraction analysis exhibit rotational disorder (of the molecules, aggregates or crystallites) about a preferred axis, resulting in cylindrical averaging of the diffracted intensity in reciprocal space. Therefore, fibre diffraction analysis can be thought of as `structure determination from cylindrically averaged diffraction intensities' (Millane, 1993[link]). In a powder specimen the crystallites are completely (spherically) disordered, so that structure determination by fibre diffraction can be considered to be intermediate between structure determination from single crystals and from powders.

This section is a review of the theory and techniques of structure determination by X-ray fibre diffraction analysis. It includes descriptions of fibre specimens, the theory of diffraction by these specimens, intensity data collection and processing, and the variety of structure determination methods used for the various kinds of specimens studied by fibre diffraction. It does not include descriptions of specimen preparation (those can be found in the references given for specific systems), or of applications of X-ray diffraction to determining polymer morphology (e.g. particle or void sizes and shapes, texture, domain structure etc.).

References

First citationArnott, S. (1980). Twenty years hard labor as a fibre diffractionist. In Fibre diffraction methods, ACS Symposium Series, Vol. 141, edited by A. D. French & K. H. Gardner, pp. 1–30. Washington DC: American Chemical Society.Google Scholar
First citationArnott, S. & Mitra, A. K. (1984). X-ray diffraction analyses of glycosamionoglycans. In Molecular biophysics of the extracellular matrix, edited by S. Arnott, D. A. Rees & E. R. Morris, pp. 41–67. Clifton: Humana Press.Google Scholar
First citationAtkins, E. D. T. (1989). Crystal structure by X-ray diffraction. In Comprehensive polymer science, Vol. 1. Polymer characterization, edited by G. A. Allen, pp. 613–650. Oxford: Pergamon Press.Google Scholar
First citationFrench, A. D. & Gardner, K. H. (1980). Editors. Fibre diffraction methods. ACS Symposium Series, Vol. 141. Washington DC: American Chemical Society.Google Scholar
First citationHall, I. H. (1984). Editor. Structure of crystalline polymers. New York: Elsevier.Google Scholar
First citationMillane, R. P. (1988). X-ray fibre diffraction. In Crystallographic computing 4. Techniques and new technologies, edited by N. W. Isaacs & M. R. Taylor, pp. 169–186. Oxford University Press.Google Scholar
First citationMillane, R. P. (1990c). Polysaccharide structures: X-ray fibre diffraction studies. In Computer modeling of carbohydrate molecules. ACS Symposium Series No. 430, edited by A. D. French & J. W. Brady, pp. 315–331. Washington DC: American Chemical Society.Google Scholar
First citationMillane, R. P. (1993). Image reconstruction from cylindrically averaged diffraction intensities. In Digital image recovery and synthesis II, Proc. SPIE, Vol. 2029, edited by P. S. Idell, pp. 137–143. Bellingham, WA: SPIE.Google Scholar
First citationSquire, J. M. & Vibert, P. J. (1987). Editors. Fibrous protein structure. London: Academic Press.Google Scholar
First citationStubbs, G. (1999). Developments in fiber diffraction. Curr. Opin. Struct. Biol. 9, 615–619.Google Scholar
First citationVibert, P. J. (1987). Fibre diffraction methods. In Fibrous protein structure, edited by J. M. Squire & P. J. Vibert, pp. 23–45. New York: Academic Press.Google Scholar








































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