Immunological relatedness of the sarcoplasmic reticulum Ca(2+)-ATPase and the Na+,K(+)-ATPase.
The effect of anti-ATPase antibodies with epitopes near Asp-351 (PR-8), Lys-515 (PR-11) and the ATP binding domain (D12) of the Ca(2+)-ATPase of sarcoplasmic reticulum (EC 3.6.1.38) was analyzed. The PR-8 and D12 antibodies reacted freely with the Ca(2+)-ATPase in the native membrane, indicating that their epitopes are exposed on the cytoplasmic surface. Both PR-8 and D12 interfered with the crystallization of the Ca(2+)-ATPase, suggesting that their binding sites are at interfaces between ATPase molecules. PR-11 had no effect on ATPase-ATPase interactions or on the ATPase activity of sarcoplasmic reticulum. The epitope of PR-11 is suggested to be the VIDRC sequence at residues 520-525, while that of D12 at residues 670-720 of the Ca(2+)-ATPase. The use of predictive algorithms of antigenicity for identification of potential antigenic determinants in the Ca(2+)-ATPase is analyzed.
Department of Biochemistry and Molecular Biology, State University of New York, Syracuse 13210.
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E
Molnar
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Varga
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Jona
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NW
Seidler
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Martonosi
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies / Q000276:immunology; D000911:Antibodies, Monoclonal / Q000276:immunology; D001665:Binding Sites; D000252:Calcium-Transporting ATPases / Q000276:immunology* / Q000378:metabolism / Q000648:ultrastructure; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes / Q000276:immunology; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D009711:Nucleotides / Q000378:metabolism; D010766:Phosphorylation; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology* / Q000276:immunology; D000254:Sodium-Potassium-Exchanging ATPase / Q000276:immunology* / Q000378:metabolism
D000906:Antibodies; D000911:Antibodies, Monoclonal; D000939:Epitopes; D009711:Nucleotides; D000252:Calcium-Transporting ATPases; D000254:Sodium-Potassium-Exchanging ATPase; D016650:Fluorescein-5-isothiocyanate