DppA from Plesiocystis pacifica SIR-I is a putative haloalkane dehalogenase (EC 3.8.1.5) and probably catalyzes the conversion of halogenated alkanes to the corresponding alcohols. The enzyme was expressed in Escherichia coli BL21 and purified to homogeneity by ammonium sulfate precipitation and reversed-phase and ion-exchange chromatography. The DppA protein was crystallized by the vapour-diffusion method and protein crystals suitable for data collection were obtained in the orthorhombic space group P2(1)2(1)2. The DppA crystal diffracted X-rays to 1.9 A resolution using an in-house X-ray generator.