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Nature. 2017 Nov 16;551(7680):346-351. doi: 10.1038/nature24296. Epub 2017 Nov 8.

Dynamics of P-type ATPase transport revealed by single-molecule FRET.

Author information

1
Centre for Membrane Pumps in Cells and Disease - PUMPKIN, Danish National Research Foundation & Danish Research Institute of Translational Neuroscience - DANDRITE, Nordic-EMBL Partnership for Molecular Medicine, Aarhus University, DK-8000 Aarhus C, Denmark.
2
Department of Molecular Biology and Genetics, Aarhus University, DK-8000 Aarhus C, Denmark.
3
Interdisciplinary Nanoscience Center (iNANO), Aarhus University, DK-8000 Aarhus C, Denmark.
4
Department of Physiology and Biophysics, Weill Cornell Medicine, Cornell University, New York, New York 10021, USA.
5
Aarhus Institute of Advanced Studies (AIAS), Aarhus University, DK-8000 Aarhus C, Denmark.
6
Diamond Light Source, Harwell Science and Innovation Campus, Didcot OX11 0DE, UK.
7
Department of Biomedicine, Aarhus University, DK-8000 Aarhus C, Denmark.

Abstract

Phosphorylation-type (P-type) ATPases are ubiquitous primary transporters that pump cations across cell membranes through the formation and breakdown of a phosphoenzyme intermediate. Structural investigations suggest that the transport mechanism is defined by conformational changes in the cytoplasmic domains of the protein that are allosterically coupled to transmembrane helices so as to expose ion binding sites to alternate sides of the membrane. Here, we have used single-molecule fluorescence resonance energy transfer to directly observe conformational changes associated with the functional transitions in the Listeria monocytogenes Ca2+-ATPase (LMCA1), an orthologue of eukaryotic Ca2+-ATPases. We identify key intermediates with no known crystal structures and show that Ca2+ efflux by LMCA1 is rate-limited by phosphoenzyme formation. The transport process involves reversible steps and an irreversible step that follows release of ADP and extracellular release of Ca2+.

PMID:
29144454
PMCID:
PMC5872817
DOI:
10.1038/nature24296
[Indexed for MEDLINE]
Free PMC Article

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