Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results

Heeb, Norbert V.; Mazenauer, Manuel; Wyss, Simon; Geueke, Birgit; Kohler, Hans-Peter E.; Lienemann, Peter

doi:10.1016/j.chemosphere.2018.05.057

Publication type:	Article in scientific journal
Type of review:	Not specified
Title:	Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results
Authors:	Heeb, Norbert V. Mazenauer, Manuel Wyss, Simon Geueke, Birgit Kohler, Hans-Peter E. Lienemann, Peter
et. al:	No
DOI:	10.1016/j.chemosphere.2018.05.057
Published in:	Chemosphere
Volume(Issue):	207
Page(s):	118
Pages to:	129
Issue Date:	2018
Publisher / Ed. Institution:	Elsevier
ISSN:	0045-6535 1879-1298
Language:	English
Subjects:	HBCD biotransformation; HCH-converting bacterial enzyme LinB; Michaelis-menten kinetics; Molecular docking; Sphingomonadacea; Structure prediction; Catalysis; Computer Simulation; Hydrocarbons, brominated; Kinetics; Stereoisomerism
Subject (DDC):	572: Biochemistry
Abstract:	LinB is a haloalkane dehalogenase found in Sphingobium indicum B90A, an aerobic bacterium isolated from contaminated soils of hexachlorocyclohexane (HCH) dumpsites. We showed that this enzyme also converts hexabromocyclododecanes (HBCDs). Here we give new insights in the kinetics and stereochemistry of the enzymatic transformation of δ-HBCD, which resulted in the formation of two pentabromocyclododecanols (PBCDols) as first- (P1δ, P2δ) and two tetrabromocyclododecadiols (TBCDdiols) as second-generation products (T1δ, T2δ). Enzymatic transformations of δ-HBCD, α1-PBCDol, one of the transformation products, and α2-PBCDol, its enantiomer, were studied and modeled with Michaelis-Menten (MM) kinetics. Respective MM-parameters KM, vmax, kcat/KM indicated that δ-HBCD is the best LinB substrate followed by α2- and α1-PBCDol. The stereochemistry of these transformations was modeled in silico, investigating respective enzyme-substrate (ES) and enzyme-product (EP) complexes. One of the four predicted ES-complexes led to the PBCDol product P1δ, identical to α2-PBCDol with the 1R,2R,5S,6R,9R,10S-configuration. An SN2-like substitution of bromine at C6 of δ-HBCD by Asp-108 of LinB and subsequent hydrolysis of the alkyl-enzyme led to α2-PBCDol. Modeling results further indicate that backside attacks at C1, C9 and C10 are reasonable too, selectively binding leaving bromide ions in a halide pocket found in LinB. Docking with α2-PBCDol, also allowed productive enzyme binding. A TBCD-1,5-diol with the 1S,2S,5R,6R,9S,10R-configuration is the predicted second-generation product T1δ. In conclusion, in vitro- and in silico findings now allow a detailed description of step-wise enzymatic dehalohydroxylation reactions of δ-HBCD to specific PBCDols and TBCDdiols at Å-resolution and predictions of their stereochemistry.
URI:	https://digitalcollection.zhaw.ch/handle/11475/28259
Fulltext version:	Published version
License (according to publishing contract):	Licence according to publishing contract
Departement:	Life Sciences and Facility Management
Organisational Unit:	Institute of Chemistry and Biotechnology (ICBT)
Appears in collections:	Publikationen Life Sciences und Facility Management

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Heeb, N. V., Mazenauer, M., Wyss, S., Geueke, B., Kohler, H.-P. E., & Lienemann, P. (2018). Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results. Chemosphere, 207, 118–129. https://doi.org/10.1016/j.chemosphere.2018.05.057

Heeb, N.V. et al. (2018) ‘Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results’, Chemosphere, 207, pp. 118–129. Available at: https://doi.org/10.1016/j.chemosphere.2018.05.057.

N. V. Heeb, M. Mazenauer, S. Wyss, B. Geueke, H.-P. E. Kohler, and P. Lienemann, “Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results,” Chemosphere, vol. 207, pp. 118–129, 2018, doi: 10.1016/j.chemosphere.2018.05.057.

HEEB, Norbert V., Manuel MAZENAUER, Simon WYSS, Birgit GEUEKE, Hans-Peter E. KOHLER und Peter LIENEMANN, 2018. Kinetics and stereochemistry of LinB-catalyzed δ-HBCD transformation : comparison of in vitro and in silico results. Chemosphere. 2018. Bd. 207, S. 118–129. DOI 10.1016/j.chemosphere.2018.05.057

Heeb, Norbert V., Manuel Mazenauer, Simon Wyss, Birgit Geueke, Hans-Peter E. Kohler, and Peter Lienemann. 2018. “Kinetics and Stereochemistry of LinB-Catalyzed δ-HBCD Transformation : Comparison of in Vitro and in Silico Results.” Chemosphere 207: 118–29. https://doi.org/10.1016/j.chemosphere.2018.05.057.

Heeb, Norbert V., et al. “Kinetics and Stereochemistry of LinB-Catalyzed δ-HBCD Transformation : Comparison of in Vitro and in Silico Results.” Chemosphere, vol. 207, 2018, pp. 118–29, https://doi.org/10.1016/j.chemosphere.2018.05.057.