Purification, crystallization and preliminary X-ray diffraction analysis of a novel keto-deoxy-D-galactarate (KDG) dehydratase from Agrobacterium tumefaciens

D‐Galacturonic acid is the main component of pectin. It could be used to produce affordable renewable fuels, chemicals and materials through biotechnical conversion. Keto‐deoxy‐D‐galactarate (KDG) dehydratase is an enzyme in the oxidative pathway of D‐galacturonic acid in Agrobacterium tumefaciens (At). It converts 3‐deoxy‐2‐keto‐L‐threo‐hexarate to α‐ketoglutaric semialdehyde. At KDG dehydratase was crystallized by the hanging‐drop vapour‐diffusion method. The crystals belonged to the monoclinic space group C2, with unit‐cell parameters a = 169.1, b = 117.8, c = 74.3 Å, β = 112.4° and an asymmetric unit of four monomers. X‐ray diffraction data were collected to 1.9 Å resolution using synchrotron radiation. The three‐dimensional structure of At KDG dehydratase will provide valuable information on the function of the enzyme and will allow it to be engineered for biorefinery‐based applications.