Cloning, purification, and crystallization of Escherichia colicystathionine β‐lyase

The metCgene coding for cystathionine β‐lyase of Escherichia colihas been cloned and used to construct an overproducing E. colistrain. An efficient purification scheme has been developed and the purified enzyme has been crystallized by the hanging drop vapour diffusion method using either ammonium sulfate or polyethyleneglycol 400 as precipitating agent. The crystals belong to the orthorombic space group C2221. Their unit cell parameters are . Consideration of the possible values of VMaccounts for the presence of one dimer per asymmetric unit. The crystals are suitable for X‐ray analysis and a complete native date set to 1.83 Å resolution has been collected using synchrotron radiation.