Cryo-EM structures of KdpFABC suggest a K+ transport mechanism via two inter-subunit half-channels
- P-type ATPases ubiquitously pump cations across biological membranes to maintain vital ion gradients. Among those, the chimeric K+ uptake system KdpFABC is unique. While ATP hydrolysis is accomplished by the P-type ATPase subunit KdpB, K+ has been assumed to be transported by the channel-like subunit KdpA. A first crystal structure uncovered its overall topology, suggesting such a spatial separation of energizing and transporting units. Here, we report two cryo-EM structures of the 157 kDa, asymmetric KdpFABC complex at 3.7 Å and 4.0 Å resolution in an E1 and an E2 state, respectively. Unexpectedly, the structures suggest a translocation pathway through two half-channels along KdpA and KdpB, uniting the alternating-access mechanism of actively pumping P-type ATPases with the high affinity and selectivity of K+ channels. This way, KdpFABC would function as a true chimeric complex, synergizing the best features of otherwise separately evolved transport mechanisms.
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| Author: | Charlott Stock, Lisa Hielkema, Igor TascónORCiD, Dorith WunnickeORCiD, Gerrit Tjamme Oostergetel, Mikel Azkargorta, Cristina Paulino, Inga HäneltORCiDGND |
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| URN: | urn:nbn:de:hebis:30:3-478735 |
| DOI: | https://doi.org/10.1038/s41467-018-07319-2 |
| ISSN: | 2041-1723 |
| Pubmed Id: | https://pubmed.ncbi.nlm.nih.gov/30478378 |
| Parent Title (English): | Nature Communications |
| Publisher: | Nature Publishing Group UK |
| Place of publication: | [London] |
| Document Type: | Article |
| Language: | English |
| Year of Completion: | 2018 |
| Date of first Publication: | 2018/11/26 |
| Publishing Institution: | Universitätsbibliothek Johann Christian Senckenberg |
| Release Date: | 2018/12/06 |
| Tag: | Cryoelectron microscopy; Ion transport; Permeation and transport; Potassium channels |
| Volume: | 9 |
| Issue: | 1, Art. 4971 |
| Page Number: | 10 |
| First Page: | 1 |
| Last Page: | 10 |
| Note: | Rights and permissions: 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/. |
| HeBIS-PPN: | 44004393X |
| Institutes: | Biochemie, Chemie und Pharmazie / Biochemie und Chemie |
| Dewey Decimal Classification: | 5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften |
| Sammlungen: | Universitätspublikationen |
| Licence (German): |  Creative Commons - Namensnennung 4.0 |
