2.2. Crystallization  

The purified protein was concentrated using Centricon 10 dialysis tubes to 20 mg ml⁻¹ in 10 mM MgCl₂, 100 mM sodium cacodylate pH 7.0 buffer. Crystals were obtained in hanging drops using crystallization buffer consisting of 18% PEG 4000, 10 mM MgCl₂, 100 mM sodium cacodylate pH 7.0. The protein solution (2 µl) was mixed in a 1:1 ratio with 2 µl crystallization buffer and equilibrated against a 1 ml reservoir of crystallization buffer. The crystals were cryoprotected using 25% ethylene glycol. Crystallization information is summarized in Table 2 ▸.