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Title | Inhibited KdpFABC transitions into an E1 off-cycle state. |
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Journal, issue, pages | Elife, Vol. 11, Year 2022 |
Publish date | Oct 18, 2022 |
Authors | Jakob M Silberberg / Charlott Stock / Lisa Hielkema / Robin A Corey / Jan Rheinberger / Dorith Wunnicke / Victor R A Dubach / Phillip J Stansfeld / Inga Hänelt / Cristina Paulino / |
PubMed Abstract | KdpFABC is a high-affinity prokaryotic K uptake system that forms a functional chimera between a channel-like subunit (KdpA) and a P-type ATPase (KdpB). At high K levels, KdpFABC needs to be ...KdpFABC is a high-affinity prokaryotic K uptake system that forms a functional chimera between a channel-like subunit (KdpA) and a P-type ATPase (KdpB). At high K levels, KdpFABC needs to be inhibited to prevent excessive K accumulation to the point of toxicity. This is achieved by a phosphorylation of the serine residue in the TGES motif in the A domain of the pump subunit KdpB (KdpB). Here, we explore the structural basis of inhibition by KdpB phosphorylation by determining the conformational landscape of KdpFABC under inhibiting and non-inhibiting conditions. Under turnover conditions, we identified a new inhibited KdpFABC state that we termed E1P tight, which is not part of the canonical Post-Albers transport cycle of P-type ATPases. It likely represents the biochemically described stalled E1P state adopted by KdpFABC upon KdpB phosphorylation. The E1P tight state exhibits a compact fold of the three cytoplasmic domains and is likely adopted when the transition from high-energy E1P states to E2P states is unsuccessful. This study represents a structural characterization of a biologically relevant off-cycle state in the P-type ATPase family and supports the emerging discussion of P-type ATPase regulation by such states. |
External links | Elife / PubMed:36255052 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.1 - 7.4 Å |
Structure data | EMDB-14347: Cryo-EM map of the WT KdpFABC complex in the E2-P conformation, stabilised with the inhibitor orthovanadate EMDB-14911, PDB-7zrd: EMDB-14912, PDB-7zre: EMDB-14913, PDB-7zrg: EMDB-14914, PDB-7zrh: EMDB-14915, PDB-7zri: EMDB-14916, PDB-7zrj: EMDB-14917, PDB-7zrk: EMDB-14918, PDB-7zrl: EMDB-14919, PDB-7zrm: |
Chemicals | ChemComp-K: ChemComp-CDL: ChemComp-VO4: ChemComp-ATP: ChemComp-ADP: ChemComp-MG: |
Source |
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Keywords | MEMBRANE PROTEIN / P-type ATPase / superfamily of K+ transporters (SKT) / potassium uptake system / off-cycle post-albers conformation / post-albers E1 conformation |