BioCAT's Mission: “To develop and operate state-of-the-art facilities at the Advanced Photon Source for the study of the structure and dynamics of biological systems under non-crystalline conditions similar to their functional states in living tissues.” BioCAT is organized as a National Institutes of Health (NIH) Biotechnology Research Resource and is funded by the National Center for Research Resources (NCRR). Its primary research tool is a very high brightness x-ray beam-line with an on-site biochemical preparation laboratory. The research techniques that BioCAT supports are: small- and wide-angle diffraction from biological fibers, small- and wide-angle scattering (SAXS and WAXS) from macromolecules in solution, and x-ray microprobe imaging. Fiber Diffraction Many biological fibers such as muscle, hair, and viruses have internal structure which can be probed with x-rays. Using this technique, one can study the arrangement of proteins in muscle and tendons. It may be used to understand human maladies such as heart disease and cancer. Solution Scattering (SAXS and WAXS) Most proteins can not be crystallized. For those proteins, it is possible to study their structure by analyzing the manner in which they scatter x-rays. This technique is used to study how the proteins and nucleic acids in our cells function as “molecular machines.” X-Ray Micro-Imaging When excited by high-energy x-rays, metals will fluoresce. The spectrum of x-rays emitted from the metal depends on both the metal and its environment. By illuminating a sample with tightly-focused x-rays, we can determine the content, distribution, and oxidation state of the metals present in the sample. This technique is used to help us understand how the distribution of metals (such as iron and zinc) in tissues affects such things as neurological diseases, normal human development, heart disease, and cancer.