TY  - JOUR
A1  - Stock, Charlott
A1  - Hielkema, Lisa
A1  - Tascón, Igor
A1  - Wunnicke, Dorith
A1  - Oostergetel, Gerrit Tjamme
A1  - Azkargorta, Mikel
A1  - Batista Paulino, Cristina
A1  - Hänelt, Inga
T1  - Cryo-EM structures of KdpFABC suggest a K+ transport mechanism via two inter-subunit half-channels
T2  - Nature Communications
N2  - 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.
KW  - Cryoelectron microscopy
KW  - Ion transport
KW  - Permeation and transport
KW  - Potassium channels
Y1  - 2018
UR  - http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/47873
UR  - https://nbn-resolving.org/urn:nbn:de:hebis:30:3-478735
SN  - 2041-1723
N1  - 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/.
VL  - 9
IS  - 1, Art. 4971
SP  - 1
EP  - 10
PB  - Nature Publishing Group UK
CY  - [London]
ER  -