Crystallization and Crystallographic Characterization of a Bradyrhizobium Elkanii USDA94 Haloalkane Dehalogenase Variant with an Eliminated Halide-Binding Site
Prudnikova, T., Kascakova, B., Mesters, J. R., Grinkevich, P., Havlickova, P., Mazur, A., Shaposhnikova, A., Chaloupkova, R., Damborsky, J., Kuty, M., Kuta Smatanova, I.
CRYSTALS 9: 375 (2019)
Haloalkane dehalogenases are a very important class of microbial enzymes for environmental detoxification of halogenated pollutants, for biocatalysis, biosensing and molecular tagging. The double mutant (Ile44Leu + Gln102His) of the haloalkane dehalogenase DbeA from Bradyrhizobium elkanii USDA94 (DbeA∆Cl) was constructed to study the role of the second halide-binding site previously discovered in the wild-type structure. The variant is less active, less stable in the presence of chloride ions and exhibits significantly altered substrate specificity when compared with the DbeAwt. DbeA∆Cl was crystallized using the sitting-drop vapour-diffusion procedure with further optimization by the random microseeding technique. The crystal structure of
the DbeA∆Cl has been determined and refined to the 1.4 Å resolution. The DbeA∆Cl crystals belong to monoclinic space group C121. The DbeA∆Cl molecular structure was characterized and compared
with five known haloalkane dehalogenases selected from the Protein Data Bank.