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Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli
Iron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal do...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer International Publishing
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8068687/ https://www.ncbi.nlm.nih.gov/pubmed/33559753 http://dx.doi.org/10.1007/s00775-021-01854-y |
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author | Trindade, I. B. Hernandez, G. Lebègue, E. Barrière, F. Cordeiro, T. Piccioli, M. Louro, R. O. |
author_facet | Trindade, I. B. Hernandez, G. Lebègue, E. Barrière, F. Cordeiro, T. Piccioli, M. Louro, R. O. |
author_sort | Trindade, I. B. |
collection | PubMed |
description | Iron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal does not occur spontaneously, instead this process is mediated by siderophore-interacting proteins (SIP) and/or by ferric-siderophore reductases (FSR). In the past two decades, representatives of the SIP subfamily have been structurally and biochemically characterized; however, the same was not achieved for the FSR subfamily. Here, we initiate the structural and functional characterization of FhuF, the first and only FSR ever isolated. FhuF is a globular monomeric protein mainly composed by α-helices sheltering internal cavities in a fold resembling the “palm” domain found in siderophore biosynthetic enzymes. Paramagnetic NMR spectroscopy revealed that the core of the cluster has electronic properties in line with those of previously characterized 2Fe–2S ferredoxins and differences appear to be confined to the coordination of Fe(III) in the reduced protein. In particular, the two cysteines coordinating this iron appear to have substantially different bond strengths. In similarity with the proteins from the SIP subfamily, FhuF binds both the iron-loaded and the apo forms of ferrichrome in the micromolar range and cyclic voltammetry reveals the presence of redox-Bohr effect, which broadens the range of ferric-siderophore substrates that can be thermodynamically accessible for reduction. This study suggests that despite the structural differences between FSR and SIP proteins, mechanistic similarities exist between the two classes of proteins. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00775-021-01854-y. |
format | Online Article Text |
id | pubmed-8068687 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | Springer International Publishing |
record_format | MEDLINE/PubMed |
spelling | pubmed-80686872021-05-05 Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli Trindade, I. B. Hernandez, G. Lebègue, E. Barrière, F. Cordeiro, T. Piccioli, M. Louro, R. O. J Biol Inorg Chem Original Paper Iron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal does not occur spontaneously, instead this process is mediated by siderophore-interacting proteins (SIP) and/or by ferric-siderophore reductases (FSR). In the past two decades, representatives of the SIP subfamily have been structurally and biochemically characterized; however, the same was not achieved for the FSR subfamily. Here, we initiate the structural and functional characterization of FhuF, the first and only FSR ever isolated. FhuF is a globular monomeric protein mainly composed by α-helices sheltering internal cavities in a fold resembling the “palm” domain found in siderophore biosynthetic enzymes. Paramagnetic NMR spectroscopy revealed that the core of the cluster has electronic properties in line with those of previously characterized 2Fe–2S ferredoxins and differences appear to be confined to the coordination of Fe(III) in the reduced protein. In particular, the two cysteines coordinating this iron appear to have substantially different bond strengths. In similarity with the proteins from the SIP subfamily, FhuF binds both the iron-loaded and the apo forms of ferrichrome in the micromolar range and cyclic voltammetry reveals the presence of redox-Bohr effect, which broadens the range of ferric-siderophore substrates that can be thermodynamically accessible for reduction. This study suggests that despite the structural differences between FSR and SIP proteins, mechanistic similarities exist between the two classes of proteins. [Image: see text] SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00775-021-01854-y. Springer International Publishing 2021-02-09 2021 /pmc/articles/PMC8068687/ /pubmed/33559753 http://dx.doi.org/10.1007/s00775-021-01854-y Text en © The Author(s) 2021 https://creativecommons.org/licenses/by/4.0/Open AccessThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Original Paper Trindade, I. B. Hernandez, G. Lebègue, E. Barrière, F. Cordeiro, T. Piccioli, M. Louro, R. O. Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title | Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title_full | Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title_fullStr | Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title_full_unstemmed | Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title_short | Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli |
title_sort | conjuring up a ghost: structural and functional characterization of fhuf, a ferric siderophore reductase from e. coli |
topic | Original Paper |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8068687/ https://www.ncbi.nlm.nih.gov/pubmed/33559753 http://dx.doi.org/10.1007/s00775-021-01854-y |
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