RT Journal Article
SR Electronic
T1 The crystal structure of the Ca<sup>2+</sup>-ATPase 1 from <em>Listeria monocytogenes</em> reveals a pump primed for dephosphorylation
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2020.06.23.166462
DO 10.1101/2020.06.23.166462
A1 Sara Basse Hansen
A1 Mateusz Dyla
A1 Caroline Neumann
A1 Jacob Lauwring Andersen
A1 Magnus Kjaergaard
A1 Poul Nissen
YR 2020
UL http://biorxiv.org/content/early/2020/06/23/2020.06.23.166462.abstract
AB Bacteria regulate intracellular calcium concentrations by exporting calcium from the cell using active transporters. These transporters include homologues of the mammalian sarco/endoplasmic reticulum Ca2+-ATPase (SERCA), which has served as a paradigm for the structure and mechanism of P-type ATPase ion transport. Here we present three crystal structures of the Ca2+-ATPase 1 from Listeria monocytogenes (LMCA1). Structures with BeF3− mimicking a phosphoenzyme state reveal an intermediate between the outward-open E2P and the proton-occluded E2-P* conformations known for SERCA. This suggests that LMCA1 pre-organizes for dephosphorylation already at the E2P state, consistent with the rapid dephosphorylation of this pump and observations from single-molecule studies. Comparison of ion binding sites show that an arginine side-chain occupies the position equivalent to the calcium binding site I in SERCA leaving a single Ca2+-binding site in LMCA1, corresponding to SERCA site II. Absence of putative proton pathways suggest a direct mechanism of proton counter transport through the Ca2+ exchange pathways. In total, the new structures provide insight into the evolutionary divergence and conserved features of an important class of ion transporters.Competing Interest StatementThe authors have declared no competing interest.