FBS Colloquia No.320Laboratory of Supermolecular Crystallography, Institute for Protein Research

Development of Diffraction Anomalous Fine Structure analysis (DAFS) in protein crystal

　In the 1970s, the X-ray Absorption Fine Structure analysis (XAFS) was developed to obtain the information of the target elements such as its local structure and electronic states. In addition, before XAFS method was developed, there was an X-Ray Diffraction analysis (XRD) that provides detailed information about the crystallographic structure. Since the 1990s, the Diffraction Anomalous Fine Structure analysis (DAFS), which combines XAFS and XRD, has been developed and has contributed to the analysis and understanding of properties of each atom, mainly in the field of alloys. DAFS is similar to XAFS in that it analyzes the local structure, but it has the unique feature of distinguishing and observing multiple target atoms in an asymmetric unit. On the other hand, some proteins have multiple metal atoms to achieve the functions. In order to analyze the role of each metal atom in the protein individually, we are searching for confirmation and adaptation of DAFS in protein crystals. This colloquium describes the current situation and future prospects.