Crystallization and preliminary X-ray diffraction studies of phospholipase D from Streptomyces antibioticus

Phospholipase D (E.C. 3.1.4.4) from Streptomyces antibioticus has been crystallized in six crystal forms using the hanging-drop vapour-diffusion method. The type III and V crystals belong to monoclinic and hexagonal systems, respectively. All of the other crystal forms, types I, II, IV and VI, belong to orthorhombic space group P2₁2₁2₁. Of these four types, the type VI crystals are suitable for X-ray structure determination. Crystal data for type VI crystals are: a = 50.1, b = 98.7, c = 107.6 Å, V = 532100 Å³, Z = 4 and V_m = 2.47 Å³ Da^-1. Type VI crystals diffract to at least 2.3 Å resolution. A total of 11295 independent reflections to 3 Å resolution have been collected from a type VI crystal using a conventional X-ray source, and its structural analysis is currently being conducted using isomorphous replacement methods.