Preliminary X‐ray diffraction analysis of octaprenyl pyrophosphate synthase from Escherichia coli

Octaprenyl pyrophosphate synthase (OPPs), which belongs to the E ‐type prenyltransferase family, catalyses the successive condensation of farnesyl pyrophosphate with five isopentenyl pyrophosphate molecules to form trans ‐C 40 ‐octaprenyl pyrophosphate (OPP). OPP is essential for the biosynthesis of bacterial ubiquinone or menaquinone side chains, which play an important role in the electron‐transport system. Here, Escherichia coli OPPs was expressed, purified and crystallized. The crystals, which belonged to the orthorhombic space group P 2 1 2 1 2, with unit‐cell parameters a = 117.0, b = 128.4, c = 46.4 Å, were obtained by the sitting‐drop vapour‐diffusion method and diffracted to 2.2 Å resolution. Initial phase determination by molecular replacement (MR) clearly indicated that the crystal contained one homodimer per asymmetric unit. Further model building and structural refinement are in progress.