Crystallization and characterization of the dehydrogenase domain from rat peroxisomal multifunctional enzyme type 1

Peroxisomal multifunctional enzyme type 1 from rat (perMFE-1) is a monomeric multidomain protein shown to have 2-enoyl-CoA hydratase/Δ³-Δ²-enoyl-CoA isomerase and (3S)-hydroxyacyl-CoA dehydrogenase domains followed by a C-terminal extension of 130 amino acids with unknown function apart from being a carrier of the peroxisomal targeting signal type 1. The truncated perMFE-1 without the N-terminal hydratase/isomerase domain (perMFE-1DH; residues 260–722) was overexpressed as an enzymatically active recombinant protein, purified and characterized. Using (3S)-hydroxydecanoyl-CoA as a substrate, the specific enzymatic activity of perMFE-1DH was determined to be 2.2 µmol min⁻¹ mg⁻¹, comparable with that of perMFE-1 purified from rat liver (2.8 µmol min⁻¹ mg⁻¹). The protein was crystallized in the apo form by the hanging-drop method and a complete data set to 2.45 Å resolution was collected using a rotating-anode X-ray source. The crystals have primitive tetragonal symmetry, with unit-cell parameters a = b = 125.9, c = 60.2 Å.