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dc.contributor.authorNeubert, Miranda J.
dc.contributor.authorDahlmann, Elizabeth A.
dc.contributor.authorAmbrose, Andrew
dc.contributor.authorJohnson, Michael D. L.
dc.date.accessioned2018-01-31T16:44:35Z
dc.date.available2018-01-31T16:44:35Z
dc.date.issued2017-10-18
dc.identifier.citationCopper Chaperone CupA and Zinc Control CopY Regulation of the Pneumococcal cop Operon 2017, 2 (5):e00372-17 mSphereen
dc.identifier.issn2379-5042
dc.identifier.doi10.1128/mSphere.00372-17
dc.identifier.urihttp://hdl.handle.net/10150/626457
dc.description.abstractAny metal in excess can be toxic; therefore, metal homeostasis is critical to bacterial survival. Bacteria have developed specialized metal import and export systems for this purpose. For broadly toxic metals such as copper, bacteria have evolved only export systems. The copper export system (cop operon) usually consists of the operon repressor, the copper chaperone, and the copper exporter. In Streptococcus pneumoniae, the causative agent of pneumonia, otitis media, sepsis, and meningitis, little is known about operon regulation. This is partly due to the S. pneumoniae repressor, CopY, and copper chaperone, CupA, sharing limited homology to proteins of putative related function and confirmed established systems. In this study, we examined CopY metal crosstalk, CopY interactions with CupA, and how CupA can control the oxidation state of copper. We found that CopY bound zinc and increased the DNA-binding affinity of CopY by roughly an order of magnitude over that of the apo form of CopY. Once copper displaced zinc in CopY, resulting in operon activation, CupA chelated copper from CopY. After copper was acquired from CopY or other sources, if needed, CupA facilitated the reduction of Cu2+ to Cu1+, which is the exported copper state. Taken together, these data show novel mechanisms for copper processing in S. pneumoniae. IMPORTANCE As mechanisms of copper toxicity are emerging, bacterial processing of intracellular copper, specifically inside Streptococcus pneumoniae, remains unclear. In this study, we investigated two proteins encoded by the copper export operon: the repressor, CopY, and the copper chaperone, CupA. Zinc suppressed transcription of the copper export operon by increasing the affinity of CopY for DNA. Furthermore, CupA was able to chelate copper from CopY not bound to DNA and reduce it from Cu2+ to Cu1+. This reduced copper state is essential for bacterial copper export via CopA. In view of the fact that innate immune cells use copper to kill pathogenic bacteria, understanding the mechanisms of copper export could expose new small-molecule therapeutic targets that could work synergistically with copper against pathogenic bacteria.
dc.description.sponsorshipSt. Jude ALSAC; University of Arizona Bio5en
dc.language.isoenen
dc.publisherAMER SOC MICROBIOLOGYen
dc.relation.urlhttp://msphere.asm.org/lookup/doi/10.1128/mSphere.00372-17en
dc.rightsCopyright © 2017 Neubert et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.en
dc.rights.urihttps://creativecommons.org/licenses/by/4.0/
dc.subjectchaperonesen
dc.subjectcopperen
dc.subjectheavy metalsen
dc.subjectmetalen
dc.subjectmetal resistanceen
dc.subjectoperonen
dc.subjectpneumococcusen
dc.subjectrepressoren
dc.subjectStreptococcus pneumoniaeen
dc.subjectzincen
dc.titleCopper Chaperone CupA and Zinc Control CopY Regulation of the Pneumococcal cop Operonen
dc.typeArticleen
dc.contributor.departmentUniv Arizona, Dept Immunobiolen
dc.contributor.departmentUniv Arizona, Dept Pharmaceut Scien
dc.contributor.departmentUniv Arizona, Bio5 Insten
dc.identifier.journalmSphereen
dc.description.noteOpen Access Journal.en
dc.description.collectioninformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at repository@u.library.arizona.edu.en
dc.eprint.versionFinal published versionen
refterms.dateFOA2018-06-17T05:12:42Z
html.description.abstractAny metal in excess can be toxic; therefore, metal homeostasis is critical to bacterial survival. Bacteria have developed specialized metal import and export systems for this purpose. For broadly toxic metals such as copper, bacteria have evolved only export systems. The copper export system (cop operon) usually consists of the operon repressor, the copper chaperone, and the copper exporter. In Streptococcus pneumoniae, the causative agent of pneumonia, otitis media, sepsis, and meningitis, little is known about operon regulation. This is partly due to the S. pneumoniae repressor, CopY, and copper chaperone, CupA, sharing limited homology to proteins of putative related function and confirmed established systems. In this study, we examined CopY metal crosstalk, CopY interactions with CupA, and how CupA can control the oxidation state of copper. We found that CopY bound zinc and increased the DNA-binding affinity of CopY by roughly an order of magnitude over that of the apo form of CopY. Once copper displaced zinc in CopY, resulting in operon activation, CupA chelated copper from CopY. After copper was acquired from CopY or other sources, if needed, CupA facilitated the reduction of Cu2+ to Cu1+, which is the exported copper state. Taken together, these data show novel mechanisms for copper processing in S. pneumoniae. IMPORTANCE As mechanisms of copper toxicity are emerging, bacterial processing of intracellular copper, specifically inside Streptococcus pneumoniae, remains unclear. In this study, we investigated two proteins encoded by the copper export operon: the repressor, CopY, and the copper chaperone, CupA. Zinc suppressed transcription of the copper export operon by increasing the affinity of CopY for DNA. Furthermore, CupA was able to chelate copper from CopY not bound to DNA and reduce it from Cu2+ to Cu1+. This reduced copper state is essential for bacterial copper export via CopA. In view of the fact that innate immune cells use copper to kill pathogenic bacteria, understanding the mechanisms of copper export could expose new small-molecule therapeutic targets that could work synergistically with copper against pathogenic bacteria.


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Copyright © 2017 Neubert et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.
Except where otherwise noted, this item's license is described as Copyright © 2017 Neubert et al. This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license.