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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Mechanism of selective halogenation by SyrB2: a computational study
Tomasz Borowski1, Holger Noack, Mariusz Radoń
1Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, ul. Niezapominajek 8, 30-239 Kraków, Poland. ncborows@cyf-kr.edu.pl
Journal of the American Chemical Society
|August 27, 2010
Summary
Computational studies reveal SyrB2 halogenase uses stereoisomers of an oxoferryl species in chlorination. The reaction mechanism involves C-H cleavage and rapid ligand transfer, favoring chlorination for the native substrate.
Area of Science:
- Biochemistry
- Computational Chemistry
- Enzymology
Background:
- α-ketoglutarate dependent halogenases are enzymes catalyzing chlorination reactions.
- SyrB2 is a representative enzyme in this class, crucial for understanding halogenase mechanisms.
Purpose of the Study:
- To elucidate the reaction mechanism of SyrB2 chlorination using computational methods.
- To identify the nature of the experimentally observed oxoferryl species.
Main Methods:
- Macromolecular modeling using molecular docking.
- Density Functional Theory (DFT) investigations.
- CASPT2 calculations for spin state analysis.
Main Results:
- Identified two oxoferryl species as stereoisomers differing in ligand coordination.
- Both Fe(IV)═O stereoisomers decay to Fe(III)Cl(OH)/carbon radical intermediates via C-H bond cleavage.
- Determined that ligand transfer in the rebound step is rapid and substrate-dependent, favoring chlorination for L-Thr.
Conclusions:
- The chlorination mechanism involves stereoisomeric Fe(IV)═O intermediates.
- Reaction proceeds on the quintet potential energy surface after Fe(IV)═O formation.
- Stereochemistry and ligand proximity dictate the efficiency of chlorination.
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