Site-directed mutagenesis to enable and improve crystallizability of Candida tropicalis (3R)-hydroxyacyl-CoA dehydrogenase

The N-terminal part of Candida tropicalis MFE-2 (MFE-2(h2Δ)) having two (3R)-hydroxyacyl-CoA dehydrogenases with different substrate specificities has been purified and crystallized as a recombinant protein. The expressed construct was modified so that a stabile, homogeneous protein could be obtained instead of an unstabile wild-type form with a large amount of cleavage products. Cubic crystals with unit cell parameters a = 74.895, b = 78.340, c = 95.445, and α = β = γ = 90 deg were obtained by using PEG 4000 as a precipitant. The crystals exhibit the space group P212121 and contain one molecule, consisting of two different (3R)-hydroxyacyl-CoA dehydrogenases, in the asymmetric unit. The crystals diffract to a resolution of 2.2 A at a conventional X-ray source