| X-RAY DIFFRACTION |
5.5 |
293 |
For crystallization, the original conditions were modified to obtain microcrystals. Initial crystals obtained from hanging drops under the precipitant condition: 1 M ammonium sulfate, 100 mM sodium citrate pH 5.5 were crushed under a stereomicroscope, using a crystal crusher tool (Hampton research). The reservoir solution was pipetted to the drop and the seed stock was collected by washing the drop with reservoir solution. The seed stock was transferred to a seed bead tube (Molecular Dimensions Ltd., UK), vortexed three times for 30 s each, with an interval of 30 s between each vortex, to get the final seed stock. Protein solution 15 mg/mL, precipitant solution, and seed stock were mixed with a ratio of 1:1:0.5. The mixture was vortexed for 30 s in ten-minute intervals. After 30 min, the microcrystals were centrifuged at 200 rpm and the supernatant was replaced with a precipitant solution.
Applying the same protocol, microcrystals were obtained under two precipitant conditions i.e. Precipitant 1: 1M (NH4)2SO4, 100 mM sodium citrate pH 5.5, and Precipitant 2: 200 mM (NH4)2SO4, 100 mM sodium citrate pH 5.5 and 20% PEG 6000. Microcrystals obtained under both precipitant conditions were tested for diffraction data collection |
