Crystal structure of the pyridoxal 5 '-phosphate dependent L-methionine gamma-lyase from Pseudomonas putida

L-Methionine gamma-lyase (MGL) catalyzes the pyridoxal 5'-phosphate (PLP) d ependent alpha,gamma-elimination of L-methionine. We have determined two cr ystal structures of MGL from Pseudomonas putida using MAD (multiwavelength anomalous diffraction) and molecular replacement methods. The structures ha ve been refined to an R-factor of 21.1% at 2.0 and 1.7 Angstrom resolution using synchrotron radiation diffraction data. A homotetramer with 222 symme try is built up by non-crystallographic symmetry. Two monomers associate to build the active dimer. The spatial fold of subunits, with three functiona lly distinct domains and their quarternary arrangement, is similar to those of L-cystathionine beta-lyase and L-cystathionine gamma-synthase from Esch erichia coli.