Entry Clone Accession:BC014131
Entry Clone Source:MGC
SGC Clone Accession:
Tag:N-terminal: 6XHis-tag with integrated TEV protease site: MHHHHHHSSGRENLYFQ*G
Host:E.coli BL21 (DE3) codon plus RIL (Stratagen).
Procedure:RPUSD4 protein was expressed in E.coli BL21 (DE3) codon plus RIL in TB medium in the presence of 50 μg/ml of kanamycin. Cell were grown at 37oC to an OD600 of 1.5 and induced by isopropyl-1-thio-D-galactopyranoside (IPTG), final concentration 1 mM and incubated overnight at 15oC.
The crude extract was cleared by centrifugation. The lysate was loaded onto 5 ml HiTrap column (GE Healthcare), charged with Ni2+. The column was washed with 10 CV of 20 mM HEPES pH 7.4, containing 500 mM NaCl, 50 mM imidazole, 5% glycerol, and the protein was eluted with elution buffer (20 mM HEPES pH 7.5, 500 mM NaCl, 250 mM imidazole, 5% glycerol). The protein was loaded onto Superdex200 column (26x60) (GE Healthcare), equilibrated with 20 mM PIPES, pH 6.5, 250 mM NaCl. The fractions containing RPUSD4 were pooled and further purified to homogeneity by ion-exchange chromatography on Source 30S column (10x10) (GE Healthcare), equilibrated with buffer containing 20 mM PIPES, pH 6.5, and eluted with linear gradient of NaCl up to 500 mM concentration (20 CV).
Cells were harvested by centrifugation at 7,000 rpm. The cell pellets were frozen in liquid nitrogen and stored at -80˚C. For purification, the cell paste was thawed and resuspended in lysis buffer buffer (50 mM HEPES, pH 7.4, 0.5 M NaCl, 5 mM imidazol, 2 mM β-mercaptoethanol, 5% glycerol) with protease inhibitor (1 mM phenylmethyl sulfonyl fluoride, PMSF). The cells were lysed by passing through Microfluidizer (Microfluidics Corp.) at 20,000 psi.
MassSpec:Mass spec characterization: The expected mass for RPUSD4 is 33412.98 Da, measured mass is 33411.64 Da.
Crystallization:Purified RPUSD4 protein (9.2 mg/mL) was crystallized using sitting drop vapor diffusion method at 20 °C by mixing 1 μl of the protein solution with 1 μl of the reservoir solution containing 20% PEG3350, 0.2 M CaCl2.