2000 年 42 巻 1 号 p. 87-96
The Bio-Crystallography beamline (BL41XU) dedicated for X-ray crystallography of biological macromolecules is a public beamline opened from October, 1997. The X-ray source is an in-vacuum type standard undulator at SPring-8, and a rotated inclined double-crystal monochromator includes a pin-post water cooling silicon crystal on which a tremendous heat load from the undulator deposits. The focal spot in an experimental station has a size of 200 micron and 300 micron in horizontal and vertical directions, respectively. The flux is 5×1012 photons/sec for 12.4 keV X-rays at a storage ring current of 100 mA. In order to align optical elements and a diffractometer after every changes of X-ray energy and sample-detector distance, an automated procedure has been developed within the energy range from 6.5 keV to 37.5 keV. The diffractometer specially designed for macromoleculer crystallography at BL41XU is working with a CCD detector and imaging plate detectors. BL41XU has been constructed for two scientific targets: (1) routine structure analyses of biological macromolecules on the MIR-OAS technique and (2) X-ray crystallography on biologically significant supra-complexes and macromolecules crystallized only into a small size less than 50 micron. Almost of beamline commissioning required for the first target have been completed and many crystal structures have already been reported. For the second target of beamline construction, the commissioning will be continued to open the frontier of structural biology.