KATAYAMA Tyuji Mac Science co., ltd.Chief Engineer, 技術開発本部・本部長研究室
SHIRAI Tsuyosi Graduate School of engineering, Nagoya University Associate Professor, 工学部, 助手 (00262890)
SUZUKI Atsuo Graduate School of engineering, Nagoya University Associate Professor, 工学部, 助教授 (40196788)
芦田 玉一 名古屋大学, 工学部, 教授 (10029936)
In order to increase the brilliance of incident X-ray, an automatic mirror-mirror focusing optics controlled by a computer was made. The ability of the optics was estimated in the combination of high-speed X-ray diffractometer DIP-100 (Mac science) . On the theoretical calculation, the brilliance of X-ray from the optics is 4 to 5 times higher than that from graphite monochromater, but the measured brilliance was 8 to 10 times higher. Though the manual-adjusted mirror-mirror optics requires much skill and takes long time in the adjustment of two mirrors, the automatic optics using the stepping motors was needed less than half time required for the manual adjustment, and showed high reproducibility.
In general, crystallization of proteins are the neck of X-ray crystal analysis. Relatively easily obtained crystals are very small and have the size of about 0.2x0.2x0.1mm^3. From the crystals of that size, diffraction data are able to be collected only using synchrotron X-ray, but cannot be measured precisely enough for crystal analysis on DIP-100 without mirror-mirror optics. With the automatic mirror-mirror optics, diffraction data can be collected from those crystals on DIP-100 using the rotating anode X-ray source, even though the exposure time is about 20times longer than that required in the measurement using synchrotron X-ray.
The examples of collected data using the mirror-mirror optics are following ; 1) from a crystal of alkaline cellulase with the size of 0.15_x0.10_x0.08nmm^3, diffraction data comparable to those measured with synchrotron X-ray source were collected up to 3.3* resolution , 2) from a crystal (0.9_x0.1mm^3) of module-substituted chimera hemoglobin, data were collected up to 2.5* resolution, 3) from a crystal (0.8_x0.3mm^3) of amidase C_<wlc>, about 31,000 reflections up to 3.5* resolution were measured and were merged to about 11,000 independent reflections with merging R-factor of 0.10.