title: Time-resolved x-ray diffraction studies of the sarcoplasmic reticulum membrane during active transport.
abstract: X-ray and neutron diffraction studies of oriented multilayers of a highly purified fraction of isolated sarcoplasmic reticulum (SR) have previously provided the separate profile structures of the lipid bilayer and the Ca2+-ATPase molecule within the membrane profile to approximately 10-A resolution. These studies used biosynthetically deuterated SR phospholipids incorporated isomorphously into the isolated SR membranes via phospholipid transfer proteins. Time-resolved x-ray diffraction studies of these oriented SR membrane multilayers have detected significant changes in the membrane profile structure associated with phosphorylation of the Ca2+-ATPase within a single turnover of the Ca2+-transport cycle. These studies used the flash photolysis of caged ATP to effectively synchronize the ensemble of Ca2+-ATPase molecules in the multilayer, synchrotron x-radiation to provide 100-500-ms data collection times, and double-beam spectrophotometry to monitor the Ca2+-transport process directly in the oriented SR membrane multilayer.
authors.forename: J K
authors.initials: JK
authors.lastname: Blasie
authors.forename: L G
authors.initials: LG
authors.lastname: Herbette
authors.forename: D
authors.initials: D
authors.lastname: Pascolini
authors.forename: V
authors.initials: V
authors.lastname: Skita
authors.forename: D H
authors.initials: DH
authors.lastname: Pierce
authors.forename: A
authors.initials: A
authors.lastname: Scarpa
mesh_terms: D000818:Animals; D001693:Biological Transport, Active; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D007700:Kinetics; D009132:Muscles / Q000378:metabolism; D009502:Neutrons; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D013057:Spectrum Analysis; D013997:Time Factors; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D000252:Calcium-Transporting ATPases