Crystallization and preliminary X-ray diffraction studies of the BTL2 lipase from the extremophilic microorganism Bacillus thermocatenulatus

Bacillus thermocatenulatus lipase 2 (BTL2) is a thermoalkalophilic lipase that has been reported as an enantioselective biocatalyst for diverse reactions and that heads a group of enzymes that share high resistance towards many inactivation agents (heat, organic solvents, pH etc.). This makes BTL2 an important research target because of its potential industrial applications. BTL2 was cloned and overexpressed in Escherichia coli, purified and concentrated for crystallization using the sitting-drop vapour-diffusion method at 291 K. Crystals grew from a mixture of 13% MPD and 0.2 M ammonium acetate in 0.05 M sodium citrate pH 5.5-5.6. The crystals, which belonged to the orthorhombic space group I222 with unit-cell parameters a = 73.07, b = 129.08, c = 127.49 angstrom, allowed the collection of an X-ray data set to 2.2 angstrom resolution.