Deciphering ion transport and ATPase coupling in the intersubunit tunnel of KdpFABC

  • KdpFABC, a high-affinity K+ pump, combines the ion channel KdpA and the P-type ATPase KdpB to secure survival at K+ limitation. Here, we apply a combination of cryo-EM, biochemical assays, and MD simulations to illuminate the mechanisms underlying transport and the coupling to ATP hydrolysis. We show that ions are transported via an intersubunit tunnel through KdpA and KdpB. At the subunit interface, the tunnel is constricted by a phenylalanine, which, by polarized cation-π stacking, controls K+ entry into the canonical substrate binding site (CBS) of KdpB. Within the CBS, ATPase coupling is mediated by the charge distribution between an aspartate and a lysine. Interestingly, individual elements of the ion translocation mechanism of KdpFABC identified here are conserved among a wide variety of P-type ATPases from different families. This leads us to the hypothesis that KdpB might represent an early descendant of a common ancestor of cation pumps.
Author:Jakob M. Silberberg, Robin A. CoreyORCiD, Lisa Hielkema, Charlott Stock, Phillip J. StansfeldORCiD, Cristina Batista PaulinoORCiDGND, Inga HäneltORCiDGND
Parent Title (English):Nature Communications
Publisher:Nature Publishing Group UK
Place of publication:[London]
Document Type:Article
Date of Publication (online):2021/08/24
Date of first Publication:2021/08/24
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2021/11/02
Tag:Cryoelectron microscopy; Ion transport; Permeation and transport; Potassium channels
Issue:art. 5098
Page Number:12
First Page:1
Last Page:12
The work was funded by the NWO Veni grant (722.017.001) and the NWO Start-Up grant (740.018.016) to C.P. as well as by the DFG Emmy Noether grant (HA6322/3-1), and the Life Science Bridge Award by the Aventis Foundation to IH. Research in P.J.S.’s lab is funded by Wellcome (208361/Z/17/Z), the MRC (MR/S009213/1) and BBSRC (BB/P01948X/1, BB/R002517/1, and BB/S003339/1). J.M.S. is funded by the State of Hesse in the LOEWE Schwerpunkt TRABITA and R.A.C. is funded by Wellcome (208361/Z/17/Z). This project made use of time on ARCHER, ARCHER2, and JADE granted via the UK High-End Computing Consortium for Biomolecular Simulation, HECBioSim (, supported by EPSRC (grant no. EP/R029407/1). Open Access funding enabled and organized by Projekt DEAL.
Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Licence (German):License LogoCreative Commons - Namensnennung 4.0