Development of Protein Crystallography System at Ultralow Temperature

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We have developed a total system in which X-ray diffraction data collection for protein crystallography can be performed with high resolution and high speed at an arbitrary temperature from room to liquid nitrogen temperatures. This system can perform 1) high-speed and high accuracy data collection on the X-ray diffractometer having the two-dimensional area detector equipped with an imaging plate, 2) X-ray intensity data collection at ultralow temperature and 3) real-time crystallographic calculations for structure analysis by the total system controlled by the computer workstation.We introduced a double-bent mirror monochromator system in the two-dimensional area detector. The attachments for the monochromator were developed to achieve the alignment of the beam line. In order to collect intensity data at low temperature we employed a direct freezing method for protein crystals. In case of lysozyme, it was possible to collect the data at low temperature by this method, although the mosaicity of crystals increased. To keep the crystal at low temperature, we employed a gas-flow apparatus using liquid nitrogen. It was found that this system can use for the data collection of the forzen crystals above mentioned.The total workstation network system was established to control the diffractometer and perform crystallographic calculations.