Crystallization of RNase P Complex

Preparation, purification, and folding of T. maritima RNase P and tRNA^Phe have been described8 (link),17 (link),44 (link). For crystallization, the components were mixed in a 1:1.1:1 (P RNA: pre-tRNA: protein) molar ratio to a concentration of 45 μM. The mixture was heated to 94 °C (2 min), cooled to 4 °C (2 min), and after the addition of MgCl₂ to a final 10 mM concentration, further incubated at 50 °C (10 min) and 37 °C (40 min). Crystals were obtained by mixing 1 μl of complex with 1 μl of reservoir solution (1.8 M Li₂SO₄, 50 mM sodium cacodylate (pH 6.0)) and equilibrated by vapor diffusion at 30 °C. Crystals were cryo-protected using 15% xylitol plus reservoir solution.