Structural and functional analysis of a novel haloalkane dehalogenase with two halide-binding sites

Two halide-binding sites were identified in the crystal structure of the newly isolated haloalkane dehalogenase DbeA from Bradyrhizobium elkanii USDA94. Elimination of the second halide-binding site significantly modified the enzyme substrate specificity, catalytic activity and stability in the presence of chloride salts. A shift in the substrate-specificity class after mutagenesis was demonstrated for the first time for haloalkane dehalogenases.