9GQO image
Entry Detail
PDB ID:
9GQO
EMDB ID:
Title:
Structure of a Ca2+ bound phosphoenzyme intermediate in the inward-to-outward transition of Ca2+-ATPase 1 from Listeria monocytogenes
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2024-09-09
Release Date:
2024-10-16
Method Details:
Experimental Method:
Resolution:
3.46 Å
Aggregation State:
PARTICLE
Reconstruction Method:
SINGLE PARTICLE
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Calcium-transporting ATPase lmo0841
Chain IDs:A
Chain Length:911
Number of Molecules:1
Biological Source:Listeria monocytogenes
Primary Citation
Structure of the [Ca]E2P intermediate of Ca 2+ -ATPase 1 from Listeria monocytogenes.
Embo Rep. 26 1709 1723 (2025)
PMID: 40016426 DOI: 10.1038/s44319-025-00392-x

Abstact

Active transport by P-type Ca2+-ATPases maintain internal calcium stores and a low cytosolic calcium concentration. Structural studies of mammalian sarco/endoplasmic reticulum Ca2+-ATPases (SERCA) have revealed several steps of the transport cycle, but a calcium-releasing intermediate has remained elusive. Single-molecule FRET studies of the bacterial Ca2+-ATPase LMCA1 revealed an intermediate of the transition between so-called [Ca]E1P and E2P states and suggested that calcium release from this intermediate was the essentially irreversible step of transport. Here, we present a 3.5 Å resolution cryo-EM structure for a four-glycine insertion mutant of LMCA1 in a lipid nanodisc obtained under conditions with calcium and ATP and adopting such an intermediate state, denoted [Ca]E2P. The cytosolic domains are positioned in the E2P-like conformation, while the calcium-binding transmembrane (TM) domain adopts a calcium-bound E1P-ADP-like conformation. Missing density for the E292 residue at the calcium site (the equivalent of SERCA1a E309) suggests flexibility and a site poised for calcium release and proton uptake. The structure suggests a mechanism where ADP release and re-organization of the cytoplasmic domains precede calcium release.

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