title: Cyclopiazonic acid is complexed to a divalent metal ion when bound to the sarcoplasmic reticulum Ca2+-ATPase.
abstract: We have determined the structure of the sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA) in an E2.P(i)-like form stabilized as a complex with MgF(4)(2-), an ATP analog, adenosine 5'-(beta,gamma-methylene)triphosphate (AMPPCP), and cyclopiazonic acid (CPA). The structure determined at 2.5A resolution leads to a significantly revised model of CPA binding when compared with earlier reports. It shows that a divalent metal ion is required for CPA binding through coordination of the tetramic acid moiety at a characteristic kink of the M1 helix found in all P-type ATPase structures, which is expected to be part of the cytoplasmic cation access pathway. Our model is consistent with the biochemical data on CPA function and provides new measures in structure-based drug design targeting Ca(2+)-ATPases, e.g. from pathogens. We also present an extended structural basis of ATP modulation pinpointing key residues at or near the ATP binding site. A structural comparison to the Na(+),K(+)-ATPase reveals that the Phe(93) side chain occupies the equivalent binding pocket of the CPA site in SERCA, suggesting an important role of this residue in stabilization of the potassium-occluded E2 state of Na(+),K(+)-ATPase.
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
authors.forename: Mette
authors.initials: M
authors.lastname: Laursen
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
authors.forename: Maike
authors.initials: M
authors.lastname: Bublitz
authors.affiliation: Department of Biochemistry and National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
authors.forename: Karine
authors.initials: K
authors.lastname: Moncoq
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Physiology and Biophysics, Aarhus University, Ole Worms Allé, Bldg. 1160, DK-8000 Aarhus C, Denmark.
authors.forename: Claus
authors.initials: C
authors.lastname: Olesen
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Physiology and Biophysics, Aarhus University, Ole Worms Allé, Bldg. 1160, DK-8000 Aarhus C, Denmark.
authors.forename: Jesper Vuust
authors.initials: JV
authors.lastname: Møller
authors.affiliation: Department of Biochemistry and National Institute for Nanotechnology, University of Alberta, Edmonton, Alberta T6G 2H7, Canada.
authors.forename: Howard S
authors.initials: HS
authors.lastname: Young
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark.
authors.forename: Poul
authors.initials: P
authors.lastname: Nissen
authors.affiliation: Centre for Membrane Pumps in Cells and Disease-PUMPKIN, Danish National Research Foundation Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark; Department of Molecular Biology, Aarhus University, Gustav Wieds Vej 10C, DK-8000 Aarhus C, Denmark. Electronic address: jpm@mb.au.dk.
authors.forename: J Preben
authors.initials: JP
authors.lastname: Morth
mesh_terms: D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000737:chemistry; D000818:Animals; D001665:Binding Sites / Q000502:physiology; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002413:Cations, Divalent / Q000737:chemistry* / Q000378:metabolism; D018360:Crystallography, X-Ray; D005459:Fluorides / Q000737:chemistry / Q000378:metabolism; D007211:Indoles / Q000737:chemistry*; D017616:Magnesium Compounds / Q000737:chemistry / Q000378:metabolism; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D011817:Rabbits; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases / Q000737:chemistry* / Q000378:metabolism
chemical_list: D002413:Cations, Divalent; D007211:Indoles; D017616:Magnesium Compounds; C005147:5'-adenylyl (beta,gamma-methylene)diphosphonate; C031288:magnesium fluoride; D000255:Adenosine Triphosphate; D053498:Sarcoplasmic Reticulum Calcium-Transporting ATPases; D005459:Fluorides; D002118:Calcium; C000543:cyclopiazonic acid