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dc.contributor.authorMares, Laura J.
dc.contributor.authorGarcia, Alvaro
dc.contributor.authorRasmussen, Helge H.
dc.contributor.authorCornelius, Flemming
dc.contributor.authorMahmmoud, Yasser A.
dc.contributor.authorBerlin, Joshua R.
dc.contributor.authorLev, Bogdan
dc.contributor.authorAllen, Toby W.
dc.contributor.authorClarke, Ronald J.
dc.date.accessioned2019-09-09T23:28:02Z
dc.date.available2019-09-09T23:28:02Z
dc.date.issued2014-09
dc.identifier.citationMares, L. J., Garcia, A., Rasmussen, H. H., Cornelius, F., Mahmmoud, Y. A., Berlin, J. R., … Clarke, R. J. (2014). Identification of Electric-Field-Dependent Steps in the Na+,K+-Pump Cycle. Biophysical Journal, 107(6), 1352–1363. https://doi.org/10.1016/j.bpj.2014.05.054en_AU
dc.identifier.urihttp://hdl.handle.net/2123/21048
dc.description.abstractThe charge transporting activity of the Na+,K+-ATPase depends on its surrounding electric field. To isolate which steps of the enzyme’s reaction cycle involve charge movement we have investigated the response of the voltage-sensitive fluorescent probe RH421 to interaction of the protein with benzyltriethylammonium (BTEA), which binds from the extracellular medium to the Na+,K+-ATPase’s transport sites in competition with Na+ and K+, but isn’t occluded within the protein. We find that only the occludable ions Na+, K+, Rb+ and Cs+ cause a drop in RH421 fluorescence. We conclude that RH421 detects intramembrane electric field strength changes arising from charge transport associated with conformational changes occluding the transported ions within the protein, not the electric fields of the bound ions themselves. This appears at first to conflict with electrophysiological studies suggesting extracellular Na+ or K+ binding in a high field access channel is a major electrogenic reaction of the Na+,K+-ATPase. All results can be explained consistently if ion occlusion involves local deformations in the lipid membrane surrounding the protein occurring simultaneously with conformational changes necessary for ion occlusion. The most likely origin of the RH421 fluorescence response is a change in membrane dipole potential caused by membrane deformation.en_AU
dc.description.sponsorshipAustralian Research Council, National Health and Medical Research Council (Australia)en_AU
dc.language.isoen_AUen_AU
dc.publisherElsevieren_AU
dc.relationARC DP121003548, NHMRC 633252en_AU
dc.rights© 2014. This manuscript version is made available under the CC-BY-NC-ND 4.0 licenseen_AU
dc.subjectvoltage-sensitive dyeen_AU
dc.subjectdipole potentialen_AU
dc.subjectbenzyltriethylammoniumen_AU
dc.subjectfluorescenceen_AU
dc.subjectocclusionen_AU
dc.subjection bindingen_AU
dc.titleIdentification of electric-field-dependent steps in the Na+,K+-pump cycleen_AU
dc.typeArticleen_AU
dc.subject.asrcFoR::030403 - Characterisation of Biological Macromoleculesen_AU
dc.identifier.doidx.doi.org/10.1016/j.bpj.2014.05.054
dc.type.pubtypePost-printen_AU


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