title: The ATP-binding site of Ca(2+)-ATPase revealed by electron image analysis.
abstract: The location of the ATP-binding site of a P-type ion pump, Ca(2+)-ATPase from rabbit sarcoplasmic reticulum, was examined by cryoelectron microscopy. A nonhydrolyzable analog of ATP, beta, gamma-bidentate chromium (III) complex of ATP (CrATP), was used to stabilize the enzyme in the Ca(2+)-occluded state. Tubular crystals were then induced by vanadate in the presence of EGTA, keeping CrATP bound to the enzyme. The three-dimensional structures of the crystals were determined at 14 A resolution by cryoelectron microscopy and helical image analysis. Statistical comparison of the structures with and without CrATP showed clear and significant differences at the groove proposed previously as the ATP-binding pocket.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Yonekura
authors.forename: D L
authors.initials: DL
authors.lastname: Stokes
authors.forename: H
authors.initials: H
authors.lastname: Sasabe
authors.forename: C
authors.initials: C
authors.lastname: Toyoshima
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D001665:Binding Sites; D000252:Calcium-Transporting ATPases / Q000378:metabolism / Q000648:ultrastructure*; D005615:Freezing; D007700:Kinetics; D008854:Microscopy, Electron; D008961:Models, Structural; D011487:Protein Conformation; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology
chemical_list: D000255:Adenosine Triphosphate; D000252:Calcium-Transporting ATPases