Structural and Functional Analysis of a Novel Haloalkane Dehalogenase with Two Halide-Binding Sites.
|Year of publication||2014|
|Type||Article in Periodical|
|Magazine / Source||Acta Crystallographica D|
|MU Faculty or unit|
|Keywords||haloalkane dehalogenase DbeA from Bradyrhizobium elkanii USDA94|
|Description||Crystal structure of novel haloalkane dehalogenase DbeA revealed the presence of two chloride ions buried in the protein interior. The first halide-binding site is involved in substrate binding and is present in all structurally characterized haloalkane dehalogenases. The second halide-binding site is unique to DbeA. To elucidate the role of the second halide-binding site in enzyme functionality, a two-point mutant lacking this site was constructed and characterized. These substitutions resulted in a shift of substrate-specificity class and were accompanied by decrease of enzyme activity, stability and elimination of the substrate inhibition. The changes in enzyme catalytic activity were attributed to deceleration of the rate-limiting hydrolytic step, mediated by lower basicity of the catalytic histidine.|