Crystallization and preliminary crystallographic characterization of recombinant L-methionine-alpha-deamino-gamma-mercaptomethane lyase (methioninase)

L-Methionine-alpha -deamino-gamma -mercaptomethane lyase (rMETase) is invol ved in the alpha,gamma -elimination of methionine to alpha -ketobutyrate, m ethanethiol and ammonia. The reaction catalyzed by rMETase reduces the meth ionine concentration of methionine-dependent tumor cells, arresting their g rowth. Towards the goal of developing rMETase into an effective antitumor t herapeutic and also to understand the catalytic mechanism of this enzyme, r METase from Pseudomonas putida has been expressed, purified and crystallize d. The crystals belong to space group P2(1)2(1)2 and diffract X-rays to at least 2.68 Angstrom resolution at 100 K using synchrotron radiation. The un it cell has parameters a = 152.8, b = 154.6, c = 80.8 Angstrom and contains four molecules in the asymmetric unit.