Synchrotron radiation is essential for maintaining a competitive program in X-ray crystallography. The APS is one of three high-energy, third generation synchrotron sources, the other two being the ESRF and SPRING-8. The APS undulator sources provide the highest brilliance available in the United States. In addition, the APS provides a support structure, including laboratory and office modules, that facilitates biological studies. In order to gain access to such an important research resource, researchers from Columbia, Cornell, Harvard, Memorial Sloan-Kettering Cancer Center, Massachusetts Institute of Technology, Rockefeller, and Yale formed a collaboration, NE-CAT, to construct and operate a facility at APS. Having obtained the needed funding commitments from the NIH National Center for Research Resources and the participating institutions, the formal Memorandum of Understanding between APS and NE-CAT was signed on May 3, 2002. The NE-CAT scientists are involved in a wide range of research projects. Particular emphases are placed on signal transduction, DNA transcription initiation and regulation, cell cycle regulation, virus structure and function, membrane proteins, protein folding, and enzyme structure and function. Many of the research projects focus on how biological molecules interact to form large macromolecular complexes. The macromolecules studied by NE-CAT members often involve large unit cells, small crystals, weakly diffracting crystals, and/or crystals with weak anomalous scattering. The main technological R&D thrust is developing a sector in which the beamline components, instrumentation and software are optimized for the crystallography of technically challenging molecular structures. Specific areas of technological R&D or innovation include:
- Implementation of canted dual-undulator beam lines.
- Development of a high-heat load front end for a dual-undulator configuration.
- Implementation of novel side-bounce beam lines.
- Methods for improved beam stability and control.
- Micro-diffraction capabilities for crystallographic studies of very small crystals.
- Structural determinations of weakly diffracting large unit cell macromolecules.
- Software for crystallographic reasearch.
- Robotic systems for sample auto-mounting and auto-alignment.
- Cryo-crystallography and study of radiation damage.
The user program is fully supported, with each experimental station staffed 24 hours a day. The support, provided by a combination of BS/MS technical staff, postdocs, and staff scientists, assists in all aspects of data collection and analysis. Laboratory and office space is provided for crystal growth, sample preparation, data processing, structure solution and model building.