Nano liter scale protein crystallization and development of an automatic crystal appraisal method

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One of the results of this research was development of high-speed and semi-automatic protein crystallization equipment of nano-liter scale. The device was developed using 96 format Hydra dispenser. It took more than half a day to setup 400 different crystallization experiments of 1 or 2 μL scale by hand, but with this device it become possible to setup 96 crystallization drops of 500 nL in about four minutes. Now we can try more crystallization conditions with few amount of protein sample.New crystallization plate has also been developed. The plate allows collecting an oscillation photograph of the crystal in the drop as it is. Generally, the X-ray diffraction-quality of the crystal is not proportional to the appearance of a crystal. Usually one crystal should be picked up from the crystallization drop to be exposed to X-ray to check its diffraction power. However, picking up a crystal from the drop is kind of a difficult process. It also takes time, and sometimes a crystal receives considerable physical damage. The specialized crystallization microplate makes it possible to inspect crystals in the drop directly by X-ray. The drop on the plate can be exposed to X-ray with any plate orientation. With this plate, we can check the intrinsic diffraction quality of crystals without any physical perturbations. In addition, the plate can be used for both hanging and sitting drop vapor diffusion method.In combination with the modified Hydra 96 dispenser, this microplate enables high-throughput screening of crystallization of proteins. These devices will be used as important components of the protein 3000 project that is currently carried out at our laboratory.