Cloning, expression, purification, crystallization and X-ray crystallographic analysis of the (S)-3-hydroxybutyryl-CoA dehydrogenase PaaH1 fromRalstonia eutrophaH16
The (S)-3-hydroxybutyryl-CoA dehydrogenase PaaH1 fromRalstonia eutropha(RePaaH1) is an enzyme used in the biosynthesis ofn-butanol from acetyl-CoA by the reduction of acetoacetyl-CoA to (S)-3-hydroxybutyryl-CoA. TheRePaaH1 protein was crystallized using the hanging-drop vapour-diffusion method in the presence of 1.4 Mammonium sulfate, 0.1 Msodium cacodylate pH 6.0, 0.2 Msodium chloride at 295 K. X-ray diffraction data were collected to a maximum resolution of 2.6 Å on a synchrotron beamline. The crystal belonged to space groupP3221, with unit-cell parametersa=b= 135.4,c= 97.2 Å. With three molecules per asymmetric unit, the crystal volume per unit protein weight (VM) is 2.68 Å3 Da−1, which corresponds to a solvent content of approximately 54.1%. The structure was solved by the single-wavelength anomalous dispersion method and refinement of the structure is in progress.