Structural and functional analysis of a novel haloalkane dehalogenase with two halide‐binding sites. (1st July 2014)

• Record Type: Journal Article
• Authors: Chaloupkova, Radka; Prudnikova, Tatyana; Rezacova, Pavlina; Prokop, Zbynek; Koudelakova, Tana; Daniel, Lukas; Brezovsky, Jan; Ikeda‐Ohtsubo, Wakako; Sato, Yukari; Kuty, Michal; Nagata, Yuji; Kuta Smatanova, Ivana; Damborsky, Jiri
• Is Part Of: Acta crystallographica. Volume 70:Part 7(2014:Jul.)
• Page Start: 1884
• Page End: 1897
• Publication Date: 2014-07-01
• Subjects: Biomolecules -- Structure -- Periodicals; Physical biochemistry -- Periodicals; X-ray crystallography -- Periodicals; Crystallography -- Periodicals; 572
• DOI: 10.1107/S1399004714009018
• Languages: English
• ISSNs: 0907-4449

Abstract

<abstract abstract-type="main" xml:lang="en"> <title> <x xml:space="preserve">Abstract</x> </title> <p>The crystal structure of the novel haloalkane dehalogenase DbeA from <italic>Bradyrhizobium elkanii</italic> 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.</p> </abstract>