Cargando…
Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain
Electron‐transferring flavoproteins (ETFs) have been found in all kingdoms of life, mostly assisting in shuttling electrons to the respiratory chain for ATP production. While the human (h) ETF has been studied in great detail, very little is known about the biochemical properties of the homologous p...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2019
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771786/ https://www.ncbi.nlm.nih.gov/pubmed/31081204 http://dx.doi.org/10.1111/febs.14924 |
_version_ | 1783455766823305216 |
---|---|
author | Toplak, Marina Brunner, Julia Tabib, Chaitanya R. Macheroux, Peter |
author_facet | Toplak, Marina Brunner, Julia Tabib, Chaitanya R. Macheroux, Peter |
author_sort | Toplak, Marina |
collection | PubMed |
description | Electron‐transferring flavoproteins (ETFs) have been found in all kingdoms of life, mostly assisting in shuttling electrons to the respiratory chain for ATP production. While the human (h) ETF has been studied in great detail, very little is known about the biochemical properties of the homologous protein in the model organism Saccharomyces cerevisiae (yETF). In view of the absence of client dehydrogenases, for example, the acyl‐CoA dehydrogenases involved in the β‐oxidation of fatty acids, d‐lactate dehydrogenase 2 (Dld2) appeared to be the only relevant enzyme that is serviced by yETF for electron transfer to the mitochondrial electron transport chain. However, this hypothesis was never tested experimentally. Here, we report the biochemical properties of yETF and Dld2 as well as the electron transfer reaction between the two proteins. Our study revealed that Dld2 oxidizes d‐α‐hydroxyglutarate more efficiently than d‐lactate exhibiting k (catapp)/K (Mapp) values of 1200 ± 300 m (−1)·s(−1) and 11 ± 2 m (−1)·s(−1), respectively. As expected, substrate‐reduced Dld2 very slowly reacted with oxygen or the artificial electron acceptor 2,6‐dichlorophenol indophenol. However, photoreduced Dld2 was rapidly reoxidized by oxygen, suggesting that the reaction products, that is, α‐ketoglutarate and pyruvate, ‘lock’ the reduced enzyme in an unreactive state. Interestingly, however, we could demonstrate that substrate‐reduced Dld2 rapidly transfers electrons to yETF. Therefore, we conclude that the formation of a product‐reduced Dld2 complex suppresses electron transfer to dioxygen but favors the rapid reduction in yETF, thus preventing the loss of electrons and the generation of reactive oxygen species. |
format | Online Article Text |
id | pubmed-6771786 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-67717862019-10-07 Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain Toplak, Marina Brunner, Julia Tabib, Chaitanya R. Macheroux, Peter FEBS J Original Articles Electron‐transferring flavoproteins (ETFs) have been found in all kingdoms of life, mostly assisting in shuttling electrons to the respiratory chain for ATP production. While the human (h) ETF has been studied in great detail, very little is known about the biochemical properties of the homologous protein in the model organism Saccharomyces cerevisiae (yETF). In view of the absence of client dehydrogenases, for example, the acyl‐CoA dehydrogenases involved in the β‐oxidation of fatty acids, d‐lactate dehydrogenase 2 (Dld2) appeared to be the only relevant enzyme that is serviced by yETF for electron transfer to the mitochondrial electron transport chain. However, this hypothesis was never tested experimentally. Here, we report the biochemical properties of yETF and Dld2 as well as the electron transfer reaction between the two proteins. Our study revealed that Dld2 oxidizes d‐α‐hydroxyglutarate more efficiently than d‐lactate exhibiting k (catapp)/K (Mapp) values of 1200 ± 300 m (−1)·s(−1) and 11 ± 2 m (−1)·s(−1), respectively. As expected, substrate‐reduced Dld2 very slowly reacted with oxygen or the artificial electron acceptor 2,6‐dichlorophenol indophenol. However, photoreduced Dld2 was rapidly reoxidized by oxygen, suggesting that the reaction products, that is, α‐ketoglutarate and pyruvate, ‘lock’ the reduced enzyme in an unreactive state. Interestingly, however, we could demonstrate that substrate‐reduced Dld2 rapidly transfers electrons to yETF. Therefore, we conclude that the formation of a product‐reduced Dld2 complex suppresses electron transfer to dioxygen but favors the rapid reduction in yETF, thus preventing the loss of electrons and the generation of reactive oxygen species. John Wiley and Sons Inc. 2019-05-25 2019-09 /pmc/articles/PMC6771786/ /pubmed/31081204 http://dx.doi.org/10.1111/febs.14924 Text en © 2019 The Authors The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Articles Toplak, Marina Brunner, Julia Tabib, Chaitanya R. Macheroux, Peter Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title | Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title_full | Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title_fullStr | Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title_full_unstemmed | Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title_short | Closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
title_sort | closing the gap: yeast electron‐transferring flavoprotein links the oxidation of d‐lactate and d‐α‐hydroxyglutarate to energy production via the respiratory chain |
topic | Original Articles |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6771786/ https://www.ncbi.nlm.nih.gov/pubmed/31081204 http://dx.doi.org/10.1111/febs.14924 |
work_keys_str_mv | AT toplakmarina closingthegapyeastelectrontransferringflavoproteinlinkstheoxidationofdlactateanddahydroxyglutaratetoenergyproductionviatherespiratorychain AT brunnerjulia closingthegapyeastelectrontransferringflavoproteinlinkstheoxidationofdlactateanddahydroxyglutaratetoenergyproductionviatherespiratorychain AT tabibchaitanyar closingthegapyeastelectrontransferringflavoproteinlinkstheoxidationofdlactateanddahydroxyglutaratetoenergyproductionviatherespiratorychain AT macherouxpeter closingthegapyeastelectrontransferringflavoproteinlinkstheoxidationofdlactateanddahydroxyglutaratetoenergyproductionviatherespiratorychain |