Biological Small Angle X-ray
Bridging atomic-resolution structures to molecular/subcellular structures
The SSRL Beam Line BL4-2 is a permanent experimental station for small-angle X-ray scattering and diffraction (SAXS/D) techniques dedicated to research in structural biology and biophysics. The station provides state-of-the-art experimental facilities for structural studies on biological material such as nucleic acids, proteins, protein assemblies, virus particles, biological fibers as well as lipid membranes and membrane-protein/DNA complexes. In addition to supporting SAXS experiments on biological systems in equilibrium, BL4-2 also maintains premier experimental facilities for time-resolved studies featuring a high photon flux multilayer monochromator, a fast readout photon counting detector (Pilatus 300K) and a stopped-flow device providing access to reaction time scales in the milliseconds and above. The SAXS/D instrument features a pin-hole geometry x-ray scattering camera, which can be configured in several different ways to accommodate different data collection modes and experiments, including solution scattering, low angle single crystal diffraction, fiber diffraction and gracing-incidence scattering. A customized version of the Blu-Ice/DCS software, originally developed for macromolecular crystallography experiments, is used to control the entire instrument providing an intuitive graphical user interface for all experiments.
The beam line BL4-2 is part of the SSRL Structural Molecular Biology Program and is supported by the DOE Office of Biological and Environmental Research and by the National Institutes of Health, National Institute of General Medical Sciences and the National Center for Research Resources.