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Updated: Apr 27, 2026

A Hydrogen-Deuterium Exchange Mass Spectrometry HDX-MS Platform for Investigating Peptide Biosynthetic Enzymes
Published on: May 4, 2020
Structural and functional analysis of a novel haloalkane dehalogenase with two halide-binding sites
Radka Chaloupkova1, Tatyana Prudnikova2, Pavlina Rezacova3
1Loschmidt Laboratories, Department of Experimental Biology and Research Centre for Toxic Compounds in the Environment RECETOX, Masaryk University, 625 00 Brno, Czech Republic.
Abstract:
The crystal structure of the novel haloalkane dehalogenase DbeA from Bradyrhizobium elkanii USDA94 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 in the substrate-specificity class and were accompanied by a decrease in enzyme activity, stability and the elimination of substrate inhibition. The changes in enzyme catalytic activity were attributed to deceleration of the rate-limiting hydrolytic step mediated by the lower basicity of the catalytic histidine.
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