Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate

Controlling radical intermediates and thus catalysing and directing complex radical reactions is a central feature of S-adensosylmethionine (SAM)-dependent radical enzymes. We report ab initio and DFT calculations highlighting the specific influence of ion complexation, including Mg2+, identified as...

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Main Authors: Jäger, Christof M., Croft, Anna K.
Format: Article
Published: Wiley-VCH Verlag 2017
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Online Access:https://eprints.nottingham.ac.uk/39964/
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author Jäger, Christof M.
Croft, Anna K.
author_facet Jäger, Christof M.
Croft, Anna K.
author_sort Jäger, Christof M.
building Nottingham Research Data Repository
collection Online Access
description Controlling radical intermediates and thus catalysing and directing complex radical reactions is a central feature of S-adensosylmethionine (SAM)-dependent radical enzymes. We report ab initio and DFT calculations highlighting the specific influence of ion complexation, including Mg2+, identified as a key catalytic component on radical stability and reaction control in 7-carboxy-7-deazaguanine synthase (QueE). Radical stabilisation energies (RSEs) of key intermediates and radical clock-like model systems of the enzyme-catalysed rearrangement of 6-carboxytetrahydropterin (CPH4), reveals a directing role of Mg2+ in destabilising both the substrate-derived radical and corresponding side reactions, with the effect that the experimentally-observed rearrangement becomes dominant over possible alternatives. Importantly, this is achieved with minimal disruption of the thermodynamics of the substrate itself, affording a novel mechanism for an enzyme to both maintain binding potential and accelerate the rearrangement step. Other mono and divalent ions were probed with only dicationic species achieving the necessary radical conformation to facilitate the reaction.
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spelling nottingham-399642020-05-04T18:30:14Z https://eprints.nottingham.ac.uk/39964/ Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate Jäger, Christof M. Croft, Anna K. Controlling radical intermediates and thus catalysing and directing complex radical reactions is a central feature of S-adensosylmethionine (SAM)-dependent radical enzymes. We report ab initio and DFT calculations highlighting the specific influence of ion complexation, including Mg2+, identified as a key catalytic component on radical stability and reaction control in 7-carboxy-7-deazaguanine synthase (QueE). Radical stabilisation energies (RSEs) of key intermediates and radical clock-like model systems of the enzyme-catalysed rearrangement of 6-carboxytetrahydropterin (CPH4), reveals a directing role of Mg2+ in destabilising both the substrate-derived radical and corresponding side reactions, with the effect that the experimentally-observed rearrangement becomes dominant over possible alternatives. Importantly, this is achieved with minimal disruption of the thermodynamics of the substrate itself, affording a novel mechanism for an enzyme to both maintain binding potential and accelerate the rearrangement step. Other mono and divalent ions were probed with only dicationic species achieving the necessary radical conformation to facilitate the reaction. Wiley-VCH Verlag 2017-01-18 Article PeerReviewed Jäger, Christof M. and Croft, Anna K. (2017) Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate. Chemistry - a European Journal, 23 (4). pp. 953-962. ISSN 1521-3765 Catalysis Radical SAM enzymes Radical stabilization energies Computational chemistry Radical clocks http://dx.doi.org/10.1002/chem.201604719 doi:10.1002/chem.201604719 doi:10.1002/chem.201604719
spellingShingle Catalysis
Radical SAM enzymes
Radical stabilization energies
Computational chemistry
Radical clocks
Jäger, Christof M.
Croft, Anna K.
Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title_full Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title_fullStr Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title_full_unstemmed Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title_short Radical reaction control in the AdoMet radical enzyme CDG Synthase (QueE): consolidate, destabilize, accelerate
title_sort radical reaction control in the adomet radical enzyme cdg synthase (quee): consolidate, destabilize, accelerate
topic Catalysis
Radical SAM enzymes
Radical stabilization energies
Computational chemistry
Radical clocks
url https://eprints.nottingham.ac.uk/39964/
https://eprints.nottingham.ac.uk/39964/
https://eprints.nottingham.ac.uk/39964/