Crystal Structure of the Pyridoxal 5'-phosphate Dependent L-Methionine γ-Lyase from Pseudomonas putida

L-Methionine γ-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) dependent α, γ-elimination of L-methionine. We have determined two crystal structures of MGL from Pseudonwnas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures have been refined to an R-factor of 21.1% at 2.0 and 1.7 A resolution using synchrotron radiation diffraction data. A homotetramer with 222 symmetry is built up by non-crystallographic symmetry. Two monomers associate to build the active dimer. The spatial fold of subunits, with three functionally distinct domains and their quarternary arrangement, is similar to those of L-cystathionine β-lyase and L-cystathionine γ-synthase from Escherichia coli.