Crystallization and preliminary X-ray crystallographic analysis of malonyl-CoA decarboxylase from Rhizobium leguminosarum bv. trifolii

Malonyl-CoA decarboxylase (MCD), which catalyzes the conversion of malonyl-CoA to acetyl-CoA, is an evolutionarily distinct and highly conserved enzyme. MCD does not share sequence homology with other known decarboxylases, while the enzymes from different species exhibit at least >30% sequence identity to each other. In order to provide a canonical structure of the enzyme for detailed study of its structure-function relationship, the MCD of Rhizobium leguminosarum bv. trifolii was overexpressed and crystallized. The crystals belong to the orthorhombic space group P2₁2₁2, with unit-cell parameters a = 133.45, b = 127.10, c = 66.37 Å. The asymmetric unit is likely to contain two molecules of MCD (molecular weight of 51 418 Da), with a crystal volume per protein weight (V_M) of 2.69 Å³ Da^-1 and a solvent content of about 54.3% by volume. A native data set to 3.0 Å resolution was obtained using a rotating-anode X-ray generator.