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Protein Film Infrared Electrochemistry Demonstrated for Study of H2 Oxidation by a [NiFe] Hydrogenase
Published on: December 4, 2017
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A common mechanism for coenzyme cobalamin-dependent reductive dehalogenases.
Linus O Johannissen1, David Leys2, Sam Hay2
1SYNBIOCHEM, Manchester Institute of Biotechnology, University of Manchester, 131 Princess Street, Manchester M1 7DN, UK. linus.johannissen@manchester.ac.uk sam.hay@manchester.ac.uk.
Physical Chemistry Chemical Physics : PCCP
|February 14, 2017
Summary
Cobalamin-dependent dehalogenation mechanisms differ between enzymes. This study suggests a unified mechanism involving a [CoXR] adduct in the CoI state, weakening carbon-halide bonds for organohalide breakdown.
Area of Science:
- Biochemistry
- Enzymology
- Organohalide Bioremediation
Background:
- Cobalamin-dependent enzymes catalyze biological dehalogenation.
- Previous studies proposed distinct mechanisms for NpRdhA and PceA based on organohalide-cobalamin interactions.
- Discrepancies exist between experimental observations and theoretical models regarding these interactions.
Purpose of the Study:
- To investigate and compare the interaction between organohalides and cobalamin in NpRdhA and PceA.
- To elucidate the general mechanism of cobalamin-dependent dehalogenation.
Main Methods:
- Molecular docking simulations.
- Density Functional Theory (DFT) calculations.
Main Results:
- Observed differences in organohalide binding to cobalamin in the CoII state between NpRdhA and PceA.
- Identified a conserved mechanism involving a [CoXR] adduct in the CoI state for both enzymes.
- This adduct formation weakens the carbon-halide bond, facilitating dehalogenation.
Conclusions:
- Cobalamin-dependent dehalogenation likely proceeds via a general mechanism involving a [CoXR] adduct in the CoI state.
- This mechanism explains the weakening of the carbon-halide bond across different enzymes and substrates.
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