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arXiv · 2009.05441

Atom Tunneling in the Hydroxylation Process of Taurine/$\alpha$-Ketoglutarate Dioxygenase Identified by Quantum Mechanics/Molecular Mechanics Simulations

Sonia Álvarez-Barcia·Johannes Kästner
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Abstract

TauD dioxygenase is one of the most studied $\alpha$-ketoglutarate dependent dioxygenases ($\alpha$KGDs), involved in several biotechnological applications. We investigated the key step in the catalytic cycle of the $\alpha$KGDs, the hydrogen transfer process, by a QM/MM approach (B3LYP/CHARMM22). Analysis of the charge and spin densities during the reaction demonstrates that a concerted mechanism takes place, where the H atom transfer happens simultaneously with the electron transfer from taurine to the Fe=O cofactor. We found quantum tunneling of the hydrogen atom to increase the rate constant by a factor of 40 at 5\textcelsius{}. As a consequence a quite high KIE value of close to 60 is obtained, which is consistent with the experimental value.

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Sonia Álvarez-Barcia, Johannes Kästner. 2020-09-09. Atom Tunneling in the Hydroxylation Process of Taurine/$\alpha$-Ketoglutarate Dioxygenase Identified by Quantum Mechanics/Molecular Mechanics Simulations. https://doi.org/10.1021/acs.jpcb.7b03477

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