The main scientific focus of the group is small angle X-ray scattering (SAXS) from solutions of biological macromolecules. The group runs the SAXS beamline X33 at the DORIS-III storage ring at DESY (Deutsches Elektronen-Synchrotron) and also develops advanced methods for the analysis of the X-ray and neutron scattering data. Modern mathematical techniques such as regularization, non-linear optimization, heuristic algorithms etc are employed for building three-dimensional models based on the experimental scattering data. Special emphasis is put to combining the results of SAXS with X-ray crystallography, NMR spectroscopy and electron microscopy to improve 3D model refinement. The group supports external users during their experiments at the SAXS beamline in the form of service projects, or in the case of the majority of users through collaborations where group members help the users in data collection, analysis and interpretation. Most of the groups using X33 study solutions of biological macromolecules however, there are a number of groups using X33 to investigate polymers and nanostructured materials. In addition to helping users with their experiments courses and workshops are regularly organised by the group to familiarize young scientists in the field of structural biology with state-of-the-art methods in SAXS from biological macromolecules.

The present and future work of the group includes:

• user support, and collaborative projects with external user groups; maintenance and upgrade of the SAXS beamline X33;

• design of a new high brilliance Bio-SAXS beamline for the PETRA-III storage ring to be built at DESY, Hamburg;

• development of algorithms for ab initio analysis of the tertiary and quaternary structure of proteins from X-ray and neutron scattering data;

• methods for rigid body modeling of macromolecular complexes using high resolution structures of individual domains; complementary use of SAXS with NMR, crystallography;

• parametric and non-parametric methods to characterize the structure of polydisperse systems (e.g. equilibrium protein mixtures);

• creation of an expert system for large-scale analysis of SAXS data in terms of three-dimensional models.

Externally Funded Projects

SAXIER
Project type: Design Study [RIDS-011934]
Funding organisation: EC, FP6
Project duration: December 2005 - November 2009
Web page: www.saxier.org

Project aim: To develop novel hardware and software for bio- and nanotechnology applications of the high brilliance synchrotron small-angle X-ray scattering beamlines.