Macromolecular Crystallography is a technique used to study biological molecules such as proteins, viruses and nucleic acids (RNA and DNA) to a resolution higher than ~5 Å. This high resolution helps elucidate the detailed mechanism by which these macromolecules carry out their functions in living cells and organisms. Protein molecules can crystallize under regulated conditions; the crystals are made up of multiple copies of the molecule arranged in a regular 3-dimensional lattice. The x-rays deflected ("scattered") by the atoms in equivalent positions in the crystal lattice concentrate into sharp intense spots (crystal diffraction pattern). The macromolecular structure can be determined by analysis of the intensities and positions of the diffraction spots.

The Macromolecular Crystallography Group at the Stanford Synchrotron Radiation Laboratory operates and develops beamlines providing state of the art macromolecular crystallography facilities and support for visiting researchers. Of the five beamlines currently operational, two (BL9-2 and BL1-5) are designed for MAD experiments, two side stations (BL9-1 and BL11-1) are also MAD capable at slightly reduced energy resolution and one (BL11-3) operates at a fixed energy above the Se K edge. BL7-1 is available to users in monochromatic mode; energy tunability will be implemented in 2008. Researchers from universities, industry, and government laboratories around the world can gain access to the beamline facilities by submitting a research proposal. Updates on beamline facilities and other user information are posted to the px-ssrl mailing list.