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Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer

As one of the most elegant biological processes developed in bacteria, the siderophore-mediated iron uptake demands the action of specific ATP-binding cassette (ABC) importers. Although extensive studies have been done on various ABC importers, the molecular basis of these iron-chelated-siderophore...

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Autores principales: Hu, Wenxin, Zheng, Hongjin
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8660799/
https://www.ncbi.nlm.nih.gov/pubmed/34887516
http://dx.doi.org/10.1038/s42003-021-02916-2
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author Hu, Wenxin
Zheng, Hongjin
author_facet Hu, Wenxin
Zheng, Hongjin
author_sort Hu, Wenxin
collection PubMed
description As one of the most elegant biological processes developed in bacteria, the siderophore-mediated iron uptake demands the action of specific ATP-binding cassette (ABC) importers. Although extensive studies have been done on various ABC importers, the molecular basis of these iron-chelated-siderophore importers are still not fully understood. Here, we report the structure of a ferrichrome importer FhuCDB from Escherichia coli at 3.4 Å resolution determined by cryo electron microscopy. The structure revealed a monomeric membrane subunit of FhuB with a substrate translocation pathway in the middle. In the pathway, there were unique arrangements of residues, especially layers of methionines. Important residues found in the structure were interrogated by mutagenesis and functional studies. Surprisingly, the importer’s ATPase activity was decreased upon FhuD binding, which deviated from the current understanding about bacterial ABC importers. In summary, to the best of our knowledge, these studies not only reveal a new structural twist in the type II ABC importer subfamily, but also provide biological insights in the transport of iron-chelated siderophores.
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spelling pubmed-86607992021-12-27 Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer Hu, Wenxin Zheng, Hongjin Commun Biol Article As one of the most elegant biological processes developed in bacteria, the siderophore-mediated iron uptake demands the action of specific ATP-binding cassette (ABC) importers. Although extensive studies have been done on various ABC importers, the molecular basis of these iron-chelated-siderophore importers are still not fully understood. Here, we report the structure of a ferrichrome importer FhuCDB from Escherichia coli at 3.4 Å resolution determined by cryo electron microscopy. The structure revealed a monomeric membrane subunit of FhuB with a substrate translocation pathway in the middle. In the pathway, there were unique arrangements of residues, especially layers of methionines. Important residues found in the structure were interrogated by mutagenesis and functional studies. Surprisingly, the importer’s ATPase activity was decreased upon FhuD binding, which deviated from the current understanding about bacterial ABC importers. In summary, to the best of our knowledge, these studies not only reveal a new structural twist in the type II ABC importer subfamily, but also provide biological insights in the transport of iron-chelated siderophores. Nature Publishing Group UK 2021-12-09 /pmc/articles/PMC8660799/ /pubmed/34887516 http://dx.doi.org/10.1038/s42003-021-02916-2 Text en © The Author(s) 2021, corrected publication 2022 https://creativecommons.org/licenses/by/4.0/Open Access This 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 license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license 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 license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Hu, Wenxin
Zheng, Hongjin
Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title_full Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title_fullStr Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title_full_unstemmed Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title_short Cryo-EM reveals unique structural features of the FhuCDB Escherichia coli ferrichrome importer
title_sort cryo-em reveals unique structural features of the fhucdb escherichia coli ferrichrome importer
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8660799/
https://www.ncbi.nlm.nih.gov/pubmed/34887516
http://dx.doi.org/10.1038/s42003-021-02916-2
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