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[2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin

[Image: see text] Escherichia coli [2Fe-2S]-ferredoxin (Fdx) is encoded by the isc operon along with other proteins involved in the ‘house-keeping’ mechanism of iron–sulfur cluster biogenesis. Although it has been proposed that Fdx supplies electrons to reduce sulfane sulfur (S(0)) produced by the c...

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Autores principales: Kim, Jin Hae, Frederick, Ronnie O., Reinen, Nichole M., Troupis, Andrew T., Markley, John L.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: American Chemical Society 2013
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677232/
https://www.ncbi.nlm.nih.gov/pubmed/23682711
http://dx.doi.org/10.1021/ja401950a
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author Kim, Jin Hae
Frederick, Ronnie O.
Reinen, Nichole M.
Troupis, Andrew T.
Markley, John L.
author_facet Kim, Jin Hae
Frederick, Ronnie O.
Reinen, Nichole M.
Troupis, Andrew T.
Markley, John L.
author_sort Kim, Jin Hae
collection PubMed
description [Image: see text] Escherichia coli [2Fe-2S]-ferredoxin (Fdx) is encoded by the isc operon along with other proteins involved in the ‘house-keeping’ mechanism of iron–sulfur cluster biogenesis. Although it has been proposed that Fdx supplies electrons to reduce sulfane sulfur (S(0)) produced by the cysteine desulfurase (IscS) to sulfide (S(2–)) as required for the assembly of Fe–S clusters on the scaffold protein (IscU), direct experimental evidence for the role of Fdx has been lacking. Here, we show that Fdx (in either oxidation state) interacts directly with IscS. The interaction face on Fdx was found to include residues close to its Fe–S cluster. In addition, C328 of IscS, the residue known to pick up sulfur from the active site of IscS and deliver it to the Cys residues of IscU, formed a disulfide bridge with Fdx in the presence of an oxidizing agent. Electrons from reduced Fdx were transferred to IscS only in the presence of l-cysteine, but not to the C328S variant. We found that Fdx, IscU, and CyaY (the bacterial frataxin) compete for overlapping binding sites on IscS. This mutual exclusion explains the mechanism by which CyaY inhibits Fe–S cluster biogenesis. These results (1) show that reduced Fdx supplies one electron to the IscS complex as S(0) is produced by the enzymatic conversion of Cys to Ala and (2) explain the role of Fdx as a member of the isc operon.
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spelling pubmed-36772322013-06-10 [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin Kim, Jin Hae Frederick, Ronnie O. Reinen, Nichole M. Troupis, Andrew T. Markley, John L. J Am Chem Soc [Image: see text] Escherichia coli [2Fe-2S]-ferredoxin (Fdx) is encoded by the isc operon along with other proteins involved in the ‘house-keeping’ mechanism of iron–sulfur cluster biogenesis. Although it has been proposed that Fdx supplies electrons to reduce sulfane sulfur (S(0)) produced by the cysteine desulfurase (IscS) to sulfide (S(2–)) as required for the assembly of Fe–S clusters on the scaffold protein (IscU), direct experimental evidence for the role of Fdx has been lacking. Here, we show that Fdx (in either oxidation state) interacts directly with IscS. The interaction face on Fdx was found to include residues close to its Fe–S cluster. In addition, C328 of IscS, the residue known to pick up sulfur from the active site of IscS and deliver it to the Cys residues of IscU, formed a disulfide bridge with Fdx in the presence of an oxidizing agent. Electrons from reduced Fdx were transferred to IscS only in the presence of l-cysteine, but not to the C328S variant. We found that Fdx, IscU, and CyaY (the bacterial frataxin) compete for overlapping binding sites on IscS. This mutual exclusion explains the mechanism by which CyaY inhibits Fe–S cluster biogenesis. These results (1) show that reduced Fdx supplies one electron to the IscS complex as S(0) is produced by the enzymatic conversion of Cys to Ala and (2) explain the role of Fdx as a member of the isc operon. American Chemical Society 2013-05-17 2013-06-05 /pmc/articles/PMC3677232/ /pubmed/23682711 http://dx.doi.org/10.1021/ja401950a Text en Copyright © 2013 American Chemical Society Terms of Use (http://pubs.acs.org/page/policy/authorchoice_termsofuse.html)
spellingShingle Kim, Jin Hae
Frederick, Ronnie O.
Reinen, Nichole M.
Troupis, Andrew T.
Markley, John L.
[2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title_full [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title_fullStr [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title_full_unstemmed [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title_short [2Fe-2S]-Ferredoxin Binds Directly to Cysteine Desulfurase and Supplies an Electron for Iron–Sulfur Cluster Assembly but Is Displaced by the Scaffold Protein or Bacterial Frataxin
title_sort [2fe-2s]-ferredoxin binds directly to cysteine desulfurase and supplies an electron for iron–sulfur cluster assembly but is displaced by the scaffold protein or bacterial frataxin
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3677232/
https://www.ncbi.nlm.nih.gov/pubmed/23682711
http://dx.doi.org/10.1021/ja401950a
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