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Beamline: D1.2 (EMBL X33)
Small angle scattering from biological macromolecules
Beamline X33 is a bending magnet beamline for biological small-angle scattering. It uses a fixed wavelength of 1.5 Å. The endstation is equipped with a MAR Image Plate detector [345 mm] and several one- and two-dimensional gas-filled delay line detectors. The beamline is optimised for low background data collection from macromolecular solutions. A two-detector setup is available to simultaneously collect small and wide angle scattering [SAXS/WAXS] patterns.
Research at this beamline:
Small-angle X-ray scattering (SAXS) is a fundamental method in the study of biological macromolecules. SAXS allows one to study the structure of native particles in nearly physiological solutions and to analyze structural changes in response to variations in external conditions. The scattering data bear information about the overall shape and internal structure at a resolution of 1-2 nm.
The last decade brought a long-awaited breakthrough in SAXS data analysis methods allowing reliable ab initio shape and domain structure determination and detailed modeling of macromolecular complexes using rigid body refinement. This progress, coupled with advances in instrumentation significantly enhanced resolution and reliability of structural models provided by the technique. The interest in solution scattering SAXS in the biological community has grown significantly in the last years (a PubMed search of relevant papers shows that the number of publications in biological solution scattering was doubled from 2001 to 2006). The technique is especially important for macromolecular complexes and flexible systems, where the high resolution methods are hardly applicable [1].
The biological SAXS group at the EMBL, Hamburg Outstation runs the X33 scattering beamline at DORIS III and has extensive experience in providing facilities for and in organizing collaborations with groups from all over Europe. The group has developed novel approaches for SAXS data analysis [2], which, in particular, effectively incorporate information from other methods (crystallography, NMR, FRET, structure prediction etc). These programs are available on the Web and used in more than 400 laboratories worldwide. Largely thanks to these new methods, a steadily growing interest to the biological solution SAXS in the user community was observed, vividly reflected in the user statistics of X33 (from 22 groups with 36 projects in 2001 to 81 groups with 110 projects in 2006).
- B. Vestergaard et al. “The SAXS solution structure of RF1 differs from its crystal structure and is similar to its ribosome-bound cryo-EM structure”, Mol. Cell 20, 929 (2005).
- P.V. Konarev et al. “ATSAS 2.1, a program package for small-angle scattering data analysis”
J. Appl. Crystallogr. 39, 277 (2006).
