Acta Crystallographica Section A

Foundations of Crystallography

Volume 58, Part 1 (January 2002)

research papers

Acta Cryst. (2002). A58, 33-41 [ doi:10.1107/S0108767301015963 ]

Multiple diffraction data analysis for macromolecular crystals in stereoscopic multibeam imaging

C.-H. Chao, C.-Y. Hung, Y.-S. Huang, C.-H. Ching, Y.-R. Lee, Y.-C. Jean, S.-C. Lai, Y. P. Stetsko, H. Yuan and S.-L. Chang

Abstract: A detailed analysis of multiple diffraction data collected by the stereoscopic multibeam imaging technique from a tetragonal lysozyme crystal is reported. Calculations based on the dynamical theory are employed to account for diffraction profiles obtained with Bragg-angle scan in stereoscopic imaging and the conventional azimuthal scan in Renninger arrangement. The formation of a multibeam intensity profile and the relationship and mutual influence between the two scans are investigated. A simple practical method of quantitative estimation of the reflection phases of structure-factor multiplets from the experimental data obtained with two inversion-symmetry-related diffractions is proposed. The procedures for data handling and for distinguishing `partial' diffraction images from `full' diffraction images are also developed considering multibeam diffraction geometry and experimental conditions. These procedures thus provide a practical way of reconstructing diffraction profiles for experimental phase determination for macromolecular crystals.

Keywords: multiple diffraction; multibeam imaging; macromolecules.