title: Structure-function relationships of Na+/K(+)-pumps expressed in Xenopus oocytes.
abstract: During the last years we have examined structure-function relationships in the Na+/K(+)-ATPase with respect to interactions of the external cations with the pump molecule. We have analysed in voltage-clamp experiments the influence of extracellular Na+ and K+ on the current generated by Na+/K(+)-pumps expressed in Xenopus oocytes. Our results demonstrated that external Na+ and K+ have to pass an access channel in the electrical field of the membrane to reach their binding sites. This external access, therefore, is voltage-dependent and is affected by lysine residues within the cytoplasmic N-terminus, by glutamic acid residues in intramembraneous domains, the ouabain sensitivity and phosphorylation by protein kinases.
authors.affiliation: Max-Planck-Institut für Biophysik, Frankfurt/M, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Schwarz
authors.forename: L A
authors.initials: LA
authors.lastname: Vasilets
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003001:Cloning, Molecular; D005260:Female; D018698:Glutamic Acid / Q000737:chemistry / Q000235:genetics; D066298:In Vitro Techniques; D008564:Membrane Potentials; D008969:Molecular Sequence Data; D015394:Molecular Structure; D016297:Mutagenesis, Site-Directed; D009865:Oocytes / Q000378:metabolism; D010766:Phosphorylation; D000254:Sodium-Potassium-Exchanging ATPase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D014101:Torpedo / Q000235:genetics / Q000378:metabolism; D014981:Xenopus
chemical_list: D018698:Glutamic Acid; D000254:Sodium-Potassium-Exchanging ATPase