| X-RAY DIFFRACTION |
7.8 |
293 |
Once hOAT was purified, it was transferred to a 10 kDa centrifugal filter tube and concentrated to ~6 mg/mL. The holoenzyme crystals were first grown via a hanging drop vapor diffusion method. Each drop contained 2 uL of protein and 2 uL of well solution. The best crystallization condition contained 8% PEG 6000, 100 mM NaCl, 5% glycerol, and 50 mM Tricine pH 7.8. Once holoenzyme crystals reached their maximum size within seven days, 1 uL of 5-aminovaleric acid was added to the drop with crystals. The crystals were soaked for different time periods from 3 to 59 minutes. After soaking, crystals were transferred into a cryoprotective solution (well solution supplemented with 30% glycerol), and then flash-frozen in liquid nitrogen. |
