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

作者：Dyla Mateusz; Terry Daniel S; Kjaergaard Magnus; Sorensen Thomas L M; Andersen Jacob Lauwring; Andersen Jens Peter; Knudsen Charlotte Rohde; Altman Roger B; Nissen Poul^*; Blanchard Scott C^*

来源：Nature, 2017, 551(7680): 346-+.

DOI：10.1038/nature24296

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+.

• 出版日期2017-11-16