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Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT

[Image: see text] Acetylene hydratase (AH) of Pelobacter acetylenicus is a tungsten (W)-containing iron–sulfur enzyme that catalyzes the transformation of acetylene to acetaldehyde, the exact/true reaction mechanism of which is still in question. Scientists utilized different computational approache...

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Autores principales: Habib, Uzma, Riaz, Mahum, Hofmann, Matthias
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2021
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970554/
https://www.ncbi.nlm.nih.gov/pubmed/33748606
http://dx.doi.org/10.1021/acsomega.0c06159
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author Habib, Uzma
Riaz, Mahum
Hofmann, Matthias
author_facet Habib, Uzma
Riaz, Mahum
Hofmann, Matthias
author_sort Habib, Uzma
collection PubMed
description [Image: see text] Acetylene hydratase (AH) of Pelobacter acetylenicus is a tungsten (W)-containing iron–sulfur enzyme that catalyzes the transformation of acetylene to acetaldehyde, the exact/true reaction mechanism of which is still in question. Scientists utilized different computational approaches to understand the reaction mechanism of acetylene hydration. Some identified it as a multistep (4–16) process that starts with the displacement of a water molecule present at the active site of AH with acetylene. However, some said that there is no need to displace water with acetylene at the active site of AH. As the reaction mechanism for the conversion of acetylene to acetaldehyde is still controversial and needs to be investigated further, DFT studies were performed on the model complexes derived from the native protein X-ray crystal structure of AH. Based on the computational results, here we are proposing the nucleophilic reaction mechanism where the water (Wat1424) molecule is coordinated to the W center and Asp13 is assumed to be in an anionic form. The Wat1424 molecule is activated by W and then donates one of its protons to the anionic Asp13, forming the W-bound hydroxide and protonated Asp13. The W-bound hydroxide then attacks the C1 atom of acetylene together with the transfer of a proton from Asp13 to its C2 atom, resulting in the formation of a vinyl alcohol intermediate complex. The energy barrier associated with this step is 14.4 kcal/mol. The final, rate-limiting, step corresponds to the tautomerization of the vinyl alcohol intermediate to acetaldehyde via intermolecular assistance of two water molecules, associated with an energy barrier of 18.9 kcal/mol. Also, the influence of the metal on the hydration of acetylene is studied when W is replaced with Mo.
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spelling pubmed-79705542021-03-19 Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT Habib, Uzma Riaz, Mahum Hofmann, Matthias ACS Omega [Image: see text] Acetylene hydratase (AH) of Pelobacter acetylenicus is a tungsten (W)-containing iron–sulfur enzyme that catalyzes the transformation of acetylene to acetaldehyde, the exact/true reaction mechanism of which is still in question. Scientists utilized different computational approaches to understand the reaction mechanism of acetylene hydration. Some identified it as a multistep (4–16) process that starts with the displacement of a water molecule present at the active site of AH with acetylene. However, some said that there is no need to displace water with acetylene at the active site of AH. As the reaction mechanism for the conversion of acetylene to acetaldehyde is still controversial and needs to be investigated further, DFT studies were performed on the model complexes derived from the native protein X-ray crystal structure of AH. Based on the computational results, here we are proposing the nucleophilic reaction mechanism where the water (Wat1424) molecule is coordinated to the W center and Asp13 is assumed to be in an anionic form. The Wat1424 molecule is activated by W and then donates one of its protons to the anionic Asp13, forming the W-bound hydroxide and protonated Asp13. The W-bound hydroxide then attacks the C1 atom of acetylene together with the transfer of a proton from Asp13 to its C2 atom, resulting in the formation of a vinyl alcohol intermediate complex. The energy barrier associated with this step is 14.4 kcal/mol. The final, rate-limiting, step corresponds to the tautomerization of the vinyl alcohol intermediate to acetaldehyde via intermolecular assistance of two water molecules, associated with an energy barrier of 18.9 kcal/mol. Also, the influence of the metal on the hydration of acetylene is studied when W is replaced with Mo. American Chemical Society 2021-03-02 /pmc/articles/PMC7970554/ /pubmed/33748606 http://dx.doi.org/10.1021/acsomega.0c06159 Text en © 2021 The Authors. Published by American Chemical Society Permits non-commercial access and re-use, provided that author attribution and integrity are maintained; but does not permit creation of adaptations or other derivative works (https://creativecommons.org/licenses/by-nc-nd/4.0/).
spellingShingle Habib, Uzma
Riaz, Mahum
Hofmann, Matthias
Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title_full Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title_fullStr Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title_full_unstemmed Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title_short Unraveling the Way Acetaldehyde is Formed from Acetylene: A Study Based on DFT
title_sort unraveling the way acetaldehyde is formed from acetylene: a study based on dft
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7970554/
https://www.ncbi.nlm.nih.gov/pubmed/33748606
http://dx.doi.org/10.1021/acsomega.0c06159
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