Crystallographic analysis of 1,2,3-trichloropropane biodegradation by the haloalkane dehalogenase DhaA31
Language English Country United States Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
PubMed
24531456
DOI
10.1107/s1399004713026254
PII: S1399004713026254
Knihovny.cz E-resources
- Keywords
- Rhodococcus rhodochrous, alkyl-enzyme intermediate, biodegradation, chlorinated compounds, vapour-diffusion crystallization,
- MeSH
- Bacterial Proteins chemistry metabolism MeSH
- Biodegradation, Environmental MeSH
- Hydrolases chemistry metabolism MeSH
- Hydrolysis MeSH
- Catalytic Domain MeSH
- Crystallography, X-Ray MeSH
- Environmental Pollutants chemistry metabolism MeSH
- Models, Molecular MeSH
- Mutagenesis MeSH
- Propane analogs & derivatives chemistry metabolism MeSH
- Rhodococcus chemistry enzymology MeSH
- Protein Structure, Secondary MeSH
- Protein Structure, Tertiary MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- 1,2,3-trichloropropane MeSH Browser
- Bacterial Proteins MeSH
- haloalkane dehalogenase MeSH Browser
- Hydrolases MeSH
- Environmental Pollutants MeSH
- Propane MeSH
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 Å resolution crystal structure of substrate-free DhaA31, the 1.26 Å resolution structure of DhaA31 in complex with TCP and the 1.95 Å 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.
References provided by Crossref.org
A Pseudomonas putida strain genetically engineered for 1,2,3-trichloropropane bioremediation
PDB
3RK4, 4FWB, 4HZG
