The SERCA residue Glu340 mediates interdomain communication that guides Ca2+transport

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DOI

  • Maxwell M.G. Geurts, University of Oxford
  • ,
  • Johannes D. Clausen
  • ,
  • Bertrand Arnou, Universite Paris-Saclay
  • ,
  • Cédric Montigny, Universite Paris-Saclay
  • ,
  • Guillaume Lenoir, Universite Paris-Saclay
  • ,
  • Robin A. Corey, University of Oxford
  • ,
  • Christine Jaxel, Universite Paris-Saclay
  • ,
  • Jesper V. Møller
  • Poul Nissen
  • Jens Peter Andersen
  • Marc Le Maire, Universite Paris-Saclay
  • ,
  • Maike Bublitz, University of Oxford

The sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) is a P-type ATPase that transports Ca2+ from the cytosol into the sarco(endo) plasmic reticulum (SR/ER) lumen, driven by ATP. This primary transport activity depends on tight coupling between movements of the transmembrane helices forming the two Ca2+-binding sites and the cytosolic headpiece mediating ATP hydrolysis. We have addressed the molecular basis for this intramolecular communication by analyzing the structure and functional properties of the SERCA mutant E340A. The mutated Glu340 residue is strictly conserved among the P-type ATPase family of membrane transporters and is located at a seemingly strategic position at the interface between the phosphorylation domain and the cytosolic ends of 5 of SERCA's 10 transmembrane helices. The mutant displays a marked slowing of the Ca2+-binding kinetics, and its crystal structure in the presence of Ca2+ and ATP analog reveals a rotated headpiece, altered connectivity between the cytosolic domains, and an altered hydrogen bonding pattern around residue 340. Supported by molecular dynamics simulations, we conclude that the E340A mutation causes a stabilization of the Ca2+ sites in a more occluded state, hence displaying slowed dynamics. This finding underpins a crucial role of Glu340 in interdomain communication between the headpiece and the Ca2+-binding transmembrane region.

Original languageEnglish
JournalProceedings of the National Academy of Sciences of the United States of America
Volume117
Issue49
Pages (from-to)31114-31122
Number of pages9
ISSN0027-8424
DOIs
Publication statusPublished - Dec 2020

    Research areas

  • Cabinding, Molecular dynamics simulations, P-type ATPase, SERCA, Tryptophan fluorescence

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