Title:Binding of ouabain and marinobufagenin leads to different structural changes in Na,K-ATPase and depends on the enzyme conformation.
Authors:Klimanova EA; Petrushanko IY; Mitkevich VA; Anashkina AA; Orlov SN; Makarov AA; Lopina OD
Publication:FEBS Lett. 2015 Sep 14;589(19 Pt B):2668-74. doi: 10.1016/j.febslet.2015.08.011. Epub 2015 Aug 20.
Ion pump, Na,K-ATPase specifically binds cardiotonic steroids (CTS), which leads to inhibition of the enzyme activity and activation of signaling network in the cell. We have studied interaction of Na,K-ATPase with CTS of two different types - marinobufagenin and ouabain. We have shown that both CTS inhibit activity of Na,K-ATPase with the same Ki values, but binding of ouabain is sensitive to the conformation of Na,K-ATPase while binding of marinobufagenin is not. Furthermore, binding of ouabain and marinobufagenin results in different structural changes in Na,K-ATPase. Our data allow to explain the diversity of effects on the receptor function of Na,K-ATPase caused by different types of CTS.