Crystallization and preliminary X-ray studies of recombinant horseradish peroxidase

A non-glycosylated form of horseradish peroxidase c extracted from Escherichia coli inclusion bodies and refolded in the presence of haem and Ca²⁺ ions has been used to grow protein crystals suitable for X-ray diffraction analysis. The crystals are prisms in the trigonal space group P3₁12 or P3₂12 with a = b = 158.9 and c = 114.3 Å, and diffract to 1.9 Å. There are four molecules, each of 34 kDa, in the asymmetric unit. The molecules of the asymmetric unit are related by approximate translational symmetry, resulting in pseudo-centerings. Data to approximately 15 Å can thus be described by a lattice of a' = b' = 91.7 Å and c' = 57.1 Å, [alpha] = [beta] = 90° and [gamma] = 120°, including four molecules.