Crystallographic analysis of 1,2,3-trichloropropane biodegradation by the haloalkane dehalogenase DhaA31

0435285 - ÚVGZ 2015 RIV DK eng J - Článek v odborném periodiku
Lahoda, M. - Mesters, J. R. - Stsiapanava, A. - Chaloupková, R. - Kutý, Michal - Damborský, J. - Kutá-Smatanová, Ivana
Crystallographic analysis of 1,2,3-trichloropropane biodegradation by the haloalkane dehalogenase DhaA31.
Acta Crystallographica Section D-Biological Crystallography. Roč. 70, FEB 2014 (2014), s. 209-217. ISSN 0907-4449
Institucionální podpora: RVO:67179843
Klíčová slova: DhaA31 * substrate-free * 3rk4 * complex with TCP * 4fwb * wild-type DhaA * 4hzg
Kód oboru RIV: CE - Biochemie
Impakt faktor: 7.232, rok: 2013

Haloalkane dehalogenases catalyze the hydrolytic cleavage of carbon-halogen bonds, which is a key step in the aerobic mineralization of many environmental pollutants. One important pollutant is the toxic and anthropogenic compound 1,2,3-trichloropropane (TCP). Rational design was combined with saturation mutagenesis to obtain the haloalkane dehalogenase variant DhaA31, which displays an increased catalytic activity towards TCP. Here, the 1.31 angstrom resolution crystal structure of substrate-free DhaA31, the 1.26 angstrom resolution structure of DhaA31 in complex with TCP and the 1.95 angstrom resolution structure of wild-type DhaA are reported. Crystals of the enzyme-substrate complex were successfully obtained by adding volatile TCP to the reservoir after crystallization at pH 6.5 and room temperature. Comparison of the substrate-free structure with that of the DhaA31 enzyme-substrate complex reveals that the nucleophilic Asp106 changes its conformation from an inactive to an active state during the catalytic cycle. The positions of three chloride ions found inside the active site of the enzyme indicate a possible pathway for halide release from the active site through the main tunnel. Comparison of the DhaA31 variant with wild-type DhaA revealed that the introduced substitutions reduce the volume and the solvent-accessibility of the active-site pocket.
Trvalý link: http://hdl.handle.net/11104/0239193