| X-RAY DIFFRACTION |
7.0 |
298 |
Crystallization of [Fe]-hydrogenase-methenyl-H4MPT+ complex was performed in the anaerobic tent with gas phase 100%N2 at room temperature under dark condition. The reconstituted [Fe]-hydrogenase holoenzyme (50 mg/ml) was mixed with 10 mM methenyl-H4MPT+, both of which contained 10 mM MOPS/KOH pH 7.0. The final concentrations of [Fe]-hydrogenase and methenyl-H4MPT+ were 24 mg/ml and 3 mM, respectively. After incubating the mixture in this tent under dark condition for 5 min, the enzyme solution was centrifuged at 8000 rpm for 5 min by using centrifugal filters made of polyvinylidene fluoride (PVDF, Millipore). The crystallization solution contained 20% w/v polyethylene glycol 3350 and 200 mM sodium thiocyanate with a ratio of protein mixture and crystallization reservoir of 2 ul / 2 ul drops spotted on a 24 well Junior Clover plate. The crystal was soaked for a couple of seconds in 20% w/v polyethylene glycol 3350, 20% v/v glycerol and 200 mM sodium thiocyanate before freezing in liquid nitrogen. |
