Interaction between the Ca2(+)-ATPase and the proteolipid in artificial membranes.
The interaction between the Ca2+ transport ATPase and the proteolipid of rabbit sarcoplasmic reticulum was analyzed by fluorescence energy transfer, using the following donor: acceptor combinations: Ca2(+)-ATPase tryptophan----IAEDANS-proteolipid; IAEDANS-ATPase----IAF-proteolipid; IAEDANS-proteolipid----IAF-ATPase. The observed energy transfer may indicate weak interaction between the Ca2(+)-ATPase and proteolipid, but collisional energy transfer definitely contributes. The energy transfer was abolished by deoxycholate or sodium dodecylsulfate at concentrations sufficient to solubilize the membrane. In view of the low proteolipid content of sarcoplasmic reticulum and the weak interaction suggested by the energy transfer, at best only a small fraction of ATPase molecules could exist in the form of ATPase-proteolipid complexes.
Jóna
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Department of Biochemistry, Suny, Upstate Medical Center, Syracuse 132101.
Martonosi
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A
D000595:Amino Acid Sequence; D000818:Animals; D000252:Calcium-Transporting ATPases / Q000378:metabolism*; D003840:Deoxycholic Acid / Q000494:pharmacology; D004735:Energy Transfer / Q000187:drug effects; D005456:Fluorescent Dyes; D008567:Membranes, Artificial; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D011510:Proteolipids / Q000378:metabolism*; D011817:Rabbits; D012519:Sarcoplasmic Reticulum / Q000201:enzymology; D012967:Sodium Dodecyl Sulfate / Q000494:pharmacology; D013050:Spectrometry, Fluorescence
D005456:Fluorescent Dyes; D008567:Membranes, Artificial; D011510:Proteolipids; D003840:Deoxycholic Acid; D012967:Sodium Dodecyl Sulfate; D000252:Calcium-Transporting ATPases