title: Structure of the Ca2+ pump of sarcoplasmic reticulum: a view along the lipid bilayer at 9-A resolution.
abstract: We have used multilamellar crystals of the ATP-driven calcium pump from sarcoplasmic reticulum to address the structural effects of calcium binding to the enzyme. They are stacks of disk-shaped two-dimensional crystals. A density map projected along the lipid bilayer was obtained at 9-A resolution by frozen-hydrated electron microscopy. Although only in projection, much more details of the structure were revealed than previously available, especially in the transmembrane region. Quantitative comparison was made with the model obtained from the tubular crystals of this enzyme formed in the absence of calcium. Unexpectedly large differences in conformation were found, particularly in the cytoplasmic domain.
authors.affiliation: Institute of Molecular and Cellular Biosciences, University of Tokyo, Bunkyo-ku, Tokyo 113, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Ogawa
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: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000737:chemistry* / Q000378:metabolism / Q000648:ultrastructure*; D003460:Crystallization; D003593:Cytoplasm / Q000201:enzymology / Q000648:ultrastructure; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000737:chemistry* / Q000378:metabolism; D008854:Microscopy, Electron; D008958:Models, Molecular; D015394:Molecular Structure; D018482:Muscle, Skeletal / Q000201:enzymology / Q000648:ultrastructure; D011487:Protein Conformation; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology* / Q000648:ultrastructure*; D015398:Signal Transduction
chemical_list: D008051:Lipid Bilayers; D000252:Calcium-Transporting ATPases; D002118:Calcium