This article gives an overview of several basic synchrotron radi-ation (SR) X-ray analytical techniques useful for crystallographers for material characterization. They include X-ray fluorescence analysis, X-ray powder diffraction and in plane diffraction analyses, X-ray absorption fine structure analysis and X-ray photoelectron spectroscopy. Utilization of X-ray microbeam and total reflection optics are two key elements of the techniques. Special attention was paid to show the advantage of the introduction of SR to these techniques and to give a hint of SR experiments for those who have never used SR although they have basic knowledge of the techniques.
The synchrotron radiation has been extensively applied to the structure analysis in the fields of chemical crystallography; the first field is the structure analysis of the very tiny single crystals, the second is the structure analysis of the powdered samples, and the third is the time-resolved structure analysis using a single crystal or a powdered sample. Recent examples studied in the synchrotron facilities are shown in this article.
In the past ten years or so, a lot of work has been performed on the synthesis of novel ternary and more complex nitrides. This review summarizes the ternary and multinary nitrides with the coordination numbers of nitridometallate groups that are contained in the crystal structures. Subnitrides and novel compounds having Zintl anions or polyanions and nitridometallate groups are mentioned briefly.
Protein Data Bank Japan (PDBj) curates, edits, and distributes the three-dimensional biological macromolecules as one of the three members in the world-wide Protein Data Bank (wwPDB), which has been founded to maintain a single PDB Archive that is freely and publicly available to the global cnmmunity Recent activities of PDBj are introduced.
According to the progress of structural genomics projects, we have a large number of protein structures without any annotations. For the further understandings of biological systems from the view point of genome science, methods are now required to get some clues to identify the function of these“hypothetical”proteins. Here we would like to introduce several recent approaches based on protein informatics for the problem.
We successfully synthesized silicon- and germanium-based allenes as isolable crystalline compounds. These allenes were found to have bent and fluxional structure in sharp contrast to carbon allenes having rigid linear structure. Remarkable red-shifts of the absorption bands of these allenes indicate the significant interactions between two cumulative double bonds.
Recently, we succeededin vitrotime-resolved X-ray observations of picometer-scale slow Brownian motions of individual protein molecules in aqueous solutions. In this new single molecular detection system, which we call Diffracted X-ray Tracking (DXT), we observed the rotating motions of an individual nanocrystal, which is labeled to the specific site in individual protein molecules, using time-resolved Laue diffraction. DXT can monitor dynamics of the individual molecules or specific sites in individual single protein molecules. Now, we try to observe individual DNA molecules, myosin head molecules, denatured proteins, protein membranes. One of the most important technologies in DXT is fabrications of high-quality gold nanocrystals under high pressure conditions.