Crystallization and preliminary X-ray diffraction analysis of domain-chimeric L-(2S,3S)-butanediol dehydrogenase

A domain-chimeric L-2,3-butanediol dehydrogenase (chimera L-BDH), which was designed to possess both the S-configuration specificity of L-BDH and the stability of meso-BDH, was constructed by exchanging the respective domains of these two BDHs. However, chimera L-BDH possessed a lower enzymatic function than expected based on the two original enzymes. To elucidate the causes of the decreased stability and substrate specificity, crystallization of the protein was performed. Chimera L-BDH was purified to homogeneity via ammonium sulfate fractionation and three column-chromatography steps, and was crystallized using the hanging-drop vapour-diffusion method. The crystals belonged to space group C222₁, diffracted synchrotron radiation to 1.58 Å resolution and were most likely to contain two molecules in the asymmetric unit.