7lc6

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Cryo-EM Structure of KdpFABC in E2-P state with BeF3Cryo-EM Structure of KdpFABC in E2-P state with BeF3

Structural highlights

7lc6 is a 4 chain structure with sequence from Escherichia coli K-12. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:Electron Microscopy, Resolution 3.7Å
Ligands:, ,
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

KDPA_ECOLI Part of the high-affinity ATP-driven potassium transport (or Kdp) system, which catalyzes the hydrolysis of ATP coupled with the electrogenic transport of potassium into the cytoplasm (PubMed:2849541, PubMed:8499455, PubMed:23930894). This subunit binds and transports the potassium across the cytoplasmic membrane (PubMed:7896809).[1] [2] [3] [4]

Publication Abstract from PubMed

KdpFABC is an oligomeric K(+) transport complex in prokaryotes that maintains ionic homeostasis under stress conditions. The complex comprises a channel-like subunit (KdpA) from the superfamily of K(+) transporters and a pump-like subunit (KdpB) from the superfamily of P-type ATPases. Recent structural work has defined the architecture and generated contradictory hypotheses for the transport mechanism. Here, we use substrate analogs to stabilize four key intermediates in the reaction cycle and determine the corresponding structures by cryogenic electron microscopy. We find that KdpB undergoes conformational changes consistent with other representatives from the P-type superfamily, whereas KdpA, KdpC, and KdpF remain static. We observe a series of spherical densities that we assign as K(+) or water and which define a pathway for K(+) transport. This pathway runs through an intramembrane tunnel in KdpA and delivers ions to sites in the membrane domain of KdpB. Our structures suggest a mechanism where ATP hydrolysis is coupled to K(+) transfer between alternative sites in KdpB, ultimately reaching a low-affinity site where a water-filled pathway allows release of K(+) to the cytoplasm.

Structural basis for potassium transport in prokaryotes by KdpFABC.,Sweet ME, Larsen C, Zhang X, Schlame M, Pedersen BP, Stokes DL Proc Natl Acad Sci U S A. 2021 Jul 20;118(29):e2105195118. doi: , 10.1073/pnas.2105195118. PMID:34272288[5]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. ↑ Damnjanovic B, Weber A, Potschies M, Greie JC, Apell HJ. Mechanistic analysis of the pump cycle of the KdpFABC P-type ATPase. Biochemistry. 2013 Aug 20;52(33):5563-76. doi: 10.1021/bi400729e. Epub 2013 Aug, 9. PMID:23930894 doi:http://dx.doi.org/10.1021/bi400729e
  2. ↑ Siebers A, Altendorf K. The K+-translocating Kdp-ATPase from Escherichia coli. Purification, enzymatic properties and production of complex- and subunit-specific antisera. Eur J Biochem. 1988 Dec 1;178(1):131-40. PMID:2849541
  3. ↑ Buurman ET, Kim KT, Epstein W. Genetic evidence for two sequentially occupied K+ binding sites in the Kdp transport ATPase. J Biol Chem. 1995 Mar 24;270(12):6678-85. PMID:7896809
  4. ↑ Kollmann R, Altendorf K. ATP-driven potassium transport in right-side-out membrane vesicles via the Kdp system of Escherichia coli. Biochim Biophys Acta. 1993 Jun 10;1143(1):62-6. PMID:8499455
  5. ↑ Sweet ME, Larsen C, Zhang X, Schlame M, Pedersen BP, Stokes DL. Structural basis for potassium transport in prokaryotes by KdpFABC. Proc Natl Acad Sci U S A. 2021 Jul 20;118(29):e2105195118. PMID:34272288 doi:10.1073/pnas.2105195118

7lc6, resolution 3.70Å

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