Purification, crystallization and preliminary X-ray diffraction analysis of 3-ketoacyl-CoA thiolase A1887 fromRalstonia eutrophaH16
The gene product of A1887 fromRalstonia eutropha(ReH16_A1887) has been annotated as a 3-ketoacyl-CoA thiolase, an enzyme that catalyzes the fourth step of β-oxidation degradative pathways by converting 3-ketoacyl-CoA to acyl-CoA.ReH16_A1887 was overexpressed and purified to homogeneity by affinity and size-exclusion chromatography. The degradative thiolase activity of the purifiedReH16_A1887 was measured and enzyme-kinetic parameters for the protein were obtained, withKm,Vmaxandkcatvalues of 158 µM, 32 mM min−1and 5 × 106 s−1, respectively. TheReH16_A1887 protein was crystallized in 17% PEG 8K, 0.1 MHEPES pH 7.0 at 293 K and a complete data set was collected to 1.4 Å resolution. The crystal belonged to space groupP43212, with unit-cell parametersa=b= 129.52,c= 114.13 Å, α = β = γ = 90°. The asymmetric unit contained two molecules, with a solvent content of 58.9%.