Concentrations and isomer compositions of hexabromocyclododecane (HBCD) were measured in six matrices in the Czech Republic (HBCD technical mixture; consumer products; indoor and outdoor air at industrial, urban and background locations; soils; and sediments) to provide insight into changes in concentrations and isomer profiles between environmental sources and environmental sinks. A distinct gradient of air concentrations was observed, from 1600 ng/m3 in the industrial area to < 10 pg/m3 in urban and background air. Isomer profiles also showed a distinct gradient in air, from 95% γ-HBCD in industrial air to 40% γ-HBCD in background air, suggesting the influence of differential atmospheric transport and phototransformation of γ- to α-HBCD. Concentrations and isomer compositions in consumer products were highly variable and indicated differences between products with intentional addition of HBCD as a flame retardant versus those with HBCD as an impurity, e.g., from recycled plastic. Understanding the isomer-specific environmental distributions and processes remains important for risk assessment and toxicology, considering the continued use of HBCD and the isomer-specific differences in uptake, metabolism, and toxicity, and further, demonstrates the utility of isomer profiles to better understand environmental processes of HBCDs.
- MeSH
- bromované uhlovodíky analýza chemie MeSH
- isomerie MeSH
- látky znečišťující životní prostředí analýza chemie MeSH
- monitorování životního prostředí metody MeSH
- půda chemie MeSH
- retardanty hoření analýza MeSH
- spotřebitelská bezpečnost produktů MeSH
- vzduch analýza MeSH
- Publikační typ
- časopisecké články MeSH
- Geografické názvy
- Česká republika MeSH
- MeSH
- bromované uhlovodíky chemie škodlivé účinky MeSH
- endokrinní disruptory * metabolismus toxicita MeSH
- halogenované difenylethery chemie škodlivé účinky MeSH
- kontaminace potravin MeSH
- látky znečišťující životní prostředí * MeSH
- lidé MeSH
- polybrombifenylové sloučeniny chemie škodlivé účinky MeSH
- retardanty hoření * metabolismus škodlivé účinky toxicita MeSH
- sloučeniny bromu škodlivé účinky toxicita MeSH
- vystavení vlivu životního prostředí MeSH
- znečištění životního prostředí MeSH
- Check Tag
- lidé MeSH
We emphasize the importance of dynamics and hydration for enzymatic catalysis and protein design by transplanting the active site from a haloalkane dehalogenase with high enantioselectivity to nonselective dehalogenase. Protein crystallography confirms that the active site geometry of the redesigned dehalogenase matches that of the target, but its enantioselectivity remains low. Time-dependent fluorescence shifts and computer simulations revealed that dynamics and hydration at the tunnel mouth differ substantially between the redesigned and target dehalogenase.
- MeSH
- bromované uhlovodíky chemie MeSH
- fluorescenční spektrometrie MeSH
- hydrolasy chemie genetika MeSH
- katalytická doména MeSH
- katalýza MeSH
- konformace proteinů MeSH
- krystalografie rentgenová MeSH
- molekulární sekvence - údaje MeSH
- mutageneze cílená MeSH
- proteinové inženýrství * MeSH
- sekvence aminokyselin MeSH
- simulace molekulární dynamiky * MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- stereoizomerie MeSH
- voda chemie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Haloalkane dehalogenases are microbial enzymes that convert a broad range of halogenated aliphatic compounds to their corresponding alcohols by the hydrolytic mechanism. These enzymes play an important role in the biodegradation of various environmental pollutants. Haloalkane dehalogenase LinB isolated from a soil bacterium Sphingobium japonicum UT26 has a relatively broad substrate specificity and can be applied in bioremediation and biosensing of environmental pollutants. The LinB variants presented here, LinB32 and LinB70, were constructed with the goal of studying the effect of mutations on enzyme functionality. In the case of LinB32 (L117W), the introduced mutation leads to blocking of the main tunnel connecting the deeply buried active site with the surrounding solvent. The other variant, LinB70 (L44I, H107Q), has the second halide-binding site in a position analogous to that in the related haloalkane dehalogenase DbeA from Bradyrhizobium elkanii USDA94. Both LinB variants were successfully crystallized and full data sets were collected for native enzymes as well as their complexes with the substrates 1,2-dibromoethane (LinB32) and 1-bromobutane (LinB70) to resolutions ranging from 1.6 to 2.8 Å. The two mutants crystallize differently from each other, which suggests that the mutations, although deep inside the molecule, can still affect the protein crystallizability.
- MeSH
- bakteriální proteiny chemie genetika metabolismus MeSH
- biodegradace MeSH
- bromované uhlovodíky chemie metabolismus MeSH
- Escherichia coli chemie genetika MeSH
- ethylendibromid chemie metabolismus MeSH
- hydrolasy chemie genetika metabolismus MeSH
- izoenzymy chemie genetika metabolismus MeSH
- krystalizace MeSH
- krystalografie rentgenová MeSH
- rekombinantní proteiny chemie genetika metabolismus MeSH
- Sphingomonadaceae chemie enzymologie genetika MeSH
- substrátová specifita MeSH
- vazebná místa MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
