title: Distances between the functional sites of sarcoplasmic reticulum (Ca2+ + Mg2+)-ATPase and the lipid/water interface.
abstract: Measurements of fluorescence energy transfer have been performed to determine the distance between the lipid-water interface and the ATP-binding site in the (Ca2+ + Mg2+)-ATPase from sarcoplasmic reticulum. The calculated distance between the donor, FITC bound to the protein (nucleotide binding-site marker), and the acceptor, rhodamine-5'-isothiocyanyldipalmitoylphosphatidylethanolamine (RITC-DPPE) incorporated in the membrane, was in the range of 34-42 A. In addition the distance between the high affinity Ca2+-binding sites and the lipid/water interface has been calculated by luminescence energy transfer from Tb3+ bound to the Ca2+ sites to RITC-DPPE included in the membrane, and it was approx. 10 A.
mesh_terms: D000818:Animals; D001665:Binding Sites; D017301:Ca(2+) Mg(2+)-ATPase / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D004735:Energy Transfer; D016650:Fluorescein-5-isothiocyanate; D005452:Fluoresceins; D005456:Fluorescent Dyes; D010714:Phosphatidylethanolamines; D011817:Rabbits; D012235:Rhodamines; D012519:Sarcoplasmic Reticulum / Q000201:enzymology*; D013725:Terbium / Q000378:metabolism; D013861:Thiocyanates
chemical_list: D005452:Fluoresceins; D005456:Fluorescent Dyes; D010714:Phosphatidylethanolamines; D012235:Rhodamines; D013861:Thiocyanates; D013725:Terbium; C007510:1,2-dipalmitoyl-3-phosphatidylethanolamine; C027755:rhodamine isothiocyanate; D017301:Ca(2+) Mg(2+)-ATPase; D000252:Calcium-Transporting ATPases; D016650:Fluorescein-5-isothiocyanate; D002118:Calcium