Crystallization and preliminary X-ray analysis of a thermoalkalophilic lipase from Bacillus stearothermophilus L1

A thermoalkalophilic lipase from Bacillus stearothermophilus L1 (L1 lipase) was crystallized in two different crystal forms using a low concentration of the enzyme and a calcium-exchange process. The first, needle-like, crystal form, which diffracts to about 3.5 A, belongs to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 67.84, b = 72.96, c = 104.41 A. The second, monoclinic, crystal form, which behaves better than the first form for crystallographic analyses, belongs to the monoclinic space group C2 and has unit-cell parameters a = 119.62, b = 85.05, c = 98.36 A, beta = 99.73 degrees. From the monoclinic crystals, a native data set and a samarium-derivative data set were collected to 2.0 and 2.3 A resolution, respectively. The difference Patterson map between the two data sets shows strong heavy-atom peaks, indicating that the crystals are suitable for a high-resolution structure determination.