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Publication Abstract from PubMed

Many bacteria export intracellular calcium using active transporters homologous to the sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA). Here we present three crystal structures of Ca(2+)-ATPase 1 from Listeria monocytogenes (LMCA1). Structures with BeF3(-) mimicking a phosphoenzyme state reveal a closed state, which is intermediate between the outward-open E2P and the proton-occluded E2-P* conformations known for SERCA. It suggests that LMCA1 in the E2P state is pre-organized for dephosphorylation upon Ca(2+) release, consistent with the rapid dephosphorylation observed in single-molecule studies. An arginine side-chain occupies the position equivalent to calcium binding site I in SERCA, leaving a single Ca(2+)-binding site in LMCA1, corresponding to SERCA site II. Observing no putative transport pathways dedicated to protons, we infer a direct proton counter transport through the Ca(2+) exchange pathways. The LMCA1 structures provide insight into the evolutionary divergence and conserved features of this important class of ion transporters.

The crystal structure of the Ca(2+)-ATPase 1 from Listeria monocytogenes reveals a pump primed for dephosphorylation.,Basse Hansen S, Dyla M, Neumann C, Meldgaard Hoegh Quistgaard E, Lauwring Andersen J, Kjaergaard M, Nissen P J Mol Biol. 2021 Apr 29:167015. doi: 10.1016/j.jmb.2021.167015. PMID:33933469^[2]

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