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The ABC exporter IrtAB imports and reduces mycobacterial siderophores
Intracellular replication of the deadly pathogen Mycobacterium tuberculosis relies on the production of small organic molecules called siderophores to scavenge iron from host proteins(1). M. tuberculosis produces two classes of siderophores, lipid-bound mycobactin and soluble carboxymycobactin(2, 3)...
Autores principales: | , , , , , , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7170716/ https://www.ncbi.nlm.nih.gov/pubmed/32296173 http://dx.doi.org/10.1038/s41586-020-2136-9 |
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author | Arnold, Fabian M. Weber, Miriam S. Gonda, Imre Gallenito, Marc J. Adenau, Sophia Egloff, Pascal Zimmermann, Iwan Hutter, Cedric A.J. Hürlimann, Lea M. Peters, Eike Piel, Jörn Meloni, Gabriele Medalia, Ohad Seeger, Markus A. |
author_facet | Arnold, Fabian M. Weber, Miriam S. Gonda, Imre Gallenito, Marc J. Adenau, Sophia Egloff, Pascal Zimmermann, Iwan Hutter, Cedric A.J. Hürlimann, Lea M. Peters, Eike Piel, Jörn Meloni, Gabriele Medalia, Ohad Seeger, Markus A. |
author_sort | Arnold, Fabian M. |
collection | PubMed |
description | Intracellular replication of the deadly pathogen Mycobacterium tuberculosis relies on the production of small organic molecules called siderophores to scavenge iron from host proteins(1). M. tuberculosis produces two classes of siderophores, lipid-bound mycobactin and soluble carboxymycobactin(2, 3). Functional studies revealed that iron-loaded carboxymycobactin is imported into the cytoplasm by the ABC transporter IrtAB(4), which features an additional cytoplasmic siderophore interaction domain (SID)(5). However, IrtAB’s predicted ABC exporter fold seemingly contradicts its import function. Here, we show that membrane-reconstituted IrtAB is sufficient to import mycobactins, which are then reduced by the SID to facilitate iron release. Structure determination by X-ray crystallography and cryo-EM confirms IrtAB’s ABC exporter fold, but also reveals structural peculiarities at the transmembrane region of IrtAB resulting in a partially collapsed inward-facing substrate binding cavity. The SID is positioned in close proximity to the inner membrane leaflet, which allows the reduction of membrane-inserted mycobactin. Enzymatic ATPase activity and in vivo growth assays show that IrtAB prefers mycobactin over carboxymycobactin as its substrate. Our study provides insights into an unusual ABC exporter that evolved as highly specialized siderophore import machinery in mycobacteria. |
format | Online Article Text |
id | pubmed-7170716 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
record_format | MEDLINE/PubMed |
spelling | pubmed-71707162020-09-25 The ABC exporter IrtAB imports and reduces mycobacterial siderophores Arnold, Fabian M. Weber, Miriam S. Gonda, Imre Gallenito, Marc J. Adenau, Sophia Egloff, Pascal Zimmermann, Iwan Hutter, Cedric A.J. Hürlimann, Lea M. Peters, Eike Piel, Jörn Meloni, Gabriele Medalia, Ohad Seeger, Markus A. Nature Article Intracellular replication of the deadly pathogen Mycobacterium tuberculosis relies on the production of small organic molecules called siderophores to scavenge iron from host proteins(1). M. tuberculosis produces two classes of siderophores, lipid-bound mycobactin and soluble carboxymycobactin(2, 3). Functional studies revealed that iron-loaded carboxymycobactin is imported into the cytoplasm by the ABC transporter IrtAB(4), which features an additional cytoplasmic siderophore interaction domain (SID)(5). However, IrtAB’s predicted ABC exporter fold seemingly contradicts its import function. Here, we show that membrane-reconstituted IrtAB is sufficient to import mycobactins, which are then reduced by the SID to facilitate iron release. Structure determination by X-ray crystallography and cryo-EM confirms IrtAB’s ABC exporter fold, but also reveals structural peculiarities at the transmembrane region of IrtAB resulting in a partially collapsed inward-facing substrate binding cavity. The SID is positioned in close proximity to the inner membrane leaflet, which allows the reduction of membrane-inserted mycobactin. Enzymatic ATPase activity and in vivo growth assays show that IrtAB prefers mycobactin over carboxymycobactin as its substrate. Our study provides insights into an unusual ABC exporter that evolved as highly specialized siderophore import machinery in mycobacteria. 2020-03-25 2020-04 /pmc/articles/PMC7170716/ /pubmed/32296173 http://dx.doi.org/10.1038/s41586-020-2136-9 Text en http://www.nature.com/authors/editorial_policies/license.html#terms Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms |
spellingShingle | Article Arnold, Fabian M. Weber, Miriam S. Gonda, Imre Gallenito, Marc J. Adenau, Sophia Egloff, Pascal Zimmermann, Iwan Hutter, Cedric A.J. Hürlimann, Lea M. Peters, Eike Piel, Jörn Meloni, Gabriele Medalia, Ohad Seeger, Markus A. The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title | The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title_full | The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title_fullStr | The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title_full_unstemmed | The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title_short | The ABC exporter IrtAB imports and reduces mycobacterial siderophores |
title_sort | abc exporter irtab imports and reduces mycobacterial siderophores |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7170716/ https://www.ncbi.nlm.nih.gov/pubmed/32296173 http://dx.doi.org/10.1038/s41586-020-2136-9 |
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