Crystallization and preliminary X‐ray diffraction studies on recombinant isopenicillin N synthase from Aspergillus nidulans

Abstract

Recombinant Aspergillus nidulans isopenicillin N synthase was purified from an Escherichia coli expression system. The apoenzyme in the presence of saturating concentrations of MnCl₂ could be crystallized by either macro‐ or microseeding, using the hanging drop vapor diffusion technique with polyethylene glycol 8000 as precipitant. The crystals (0.5–1.0 mm overall dimensions) diffract X‐rays to at least 2.0 Å resolution at synchrotrons and belong to space group P2₁2₁2₁ with unit cell dimensions of a = 59.2 Å, b = 127.0 Å, and c = 139.6 Å. The asymmetric unit contains one dimer, and the solvent content of the crystals is 60%. The crystals are radiation sensitive.