Current Status of Public Beamlines for Protein Crystallography at SPring-8

Research & Utilization Division, Japan Synchrotron Radiation Institute (JASRI)* SPring-8/RIKEN** SPring-8/JASRI, SPring-8/RIKEN***
○Masahide KAWAMOTO* Kazuya HASEGAWA* Nobutaka SHIMIZU* Hisanobu SAKAI* Tetsuya SHIMIZU** Kunio HIRATA** Atsushi NISAWA** Masaki YAMAMOTO***

There are 9 beamlines for protein crystallography at SPring-8 as of May 2006. Two beamlines, BL38B1 (Structural Biology III) and BL41XU (Structural Biology I), out of them are dedicated for public uses.
The BL38B1 is designed based on a standard SPring-8 bending magnet beamline, consisting of a Si(111) double crystal monochrometer and a 1m-long Rh-coated cylindrical bend mirror, and used for routine protein crystallography, including the “Mail-in data collection system”. The installation of sample changer robotics, control and database system have already finished. Now we are doing final check of the entire system.
The BL41XU is an undulator beamline using the SPring-8 standard in-vacuum undulator as the light source. The undulator beam is monochromatized by rotated-inclined Si(111) double crystal monochrometer, and focused by KB mirrors. Utilizing this high brilliant X-ray beam, we are focusing on a measurement in ultra-high resolution and a data collection from micro-crystals. The large area detectors and very short wavelength X-ray from undulator 3rd harmonics enables to collect diffraction spots over 0.5 Å resolution. We have succeeded to collect a dataset of Endopolygalacturonase I at 0.68 Å resolution (R-free = 10.8%). To collect efficient quality data from micro-crystals, it is necessary to use micro-beam to reduce the background noise. Presently, the size of 25μm beam with ~10^11 photons/sec was achieved, and we could collect a dataset from lysozyme crystal sized ~20μm up to 1.9 Å resolution (R-merge = 6%)