1 National Centre for Biomolecular Research, Masaryk University, Kotlarska 2, 611 37 Brno, Czech Republic
2 Department of Environmental Life Sciences, Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Sendai 980-8577, Japan
Haloalkane dehalogenases are microbial enzymes capable to cleave carbon-halogen bond in halogenated aliphatic compounds. There is a growing interest in these enzymes because of their potential use in bioremediation, as industrial biocatalysts, or as biosensors. Structurally, haloalkane dehalogenases belong to the a/b-hydrolase fold superfamily. Best studied haloalkane dehalogeneses are DhlA from Xanthobacter autotrophicus GJ10 , DhaA from Rhodococcus rhodochrous NCIMB 13064  and LinB from Sphingomonas paucimobilis UT26 . Crystal structures of these haloalkane dehalogenases are known.
There is a number of DNA sequences which are expected to code haloalkane dehalogenases. This expectation is based on sequential similiraties with known haloalkane dehalogenases: DhlA, DhaA and LinB. Protein Rv2579 from Mycobacterium tuberculosis H37Rv has 68 % sequence similarity with LinB. Gene rv2579 was cloned to Escherichia coli, protein Rv2579 was overexpressed and purified to homogeneity. Haloalkane dehalogenase activity was confirmed with pure Rv2579 enzyme.. Protein DbjA from Bradyrhizobium japonicum USDA110 has 41 % sequence similarity with LinB. Haloalkane dehalogenase activity of DbjA was confirmed with heterogously overexperessed pure enzyme.
Increasing number of haloalkane dehalogenase group members demands
characterisation of each enzyme into more detail and substrate specificity is an
important property to be evaluated Steady-state catalytic constants are being
determined for the set of 31
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