Abstract
Recoverin, a calcium ion (Ca2+)-binding protein of vertebrate photoreceptors, binds to photoreceptor membranes when the Ca2+ concentration is greater than 1 micromolar. This interaction requires a fatty acyl residue covalently linked to the recoverin amino (NH2)-terminus. Removal of the acyl residue, either by proteolytic cleavage of the NH2-terminus or by production of nonacylated recoverin, prevented recoverin from binding to membranes. The acylated recoverin NH2-terminus could be cleaved by trypsin only when Ca2+ was bound to recoverin. These results suggest that the hydrophobic NH2-terminus is constrained in Ca(2+)-free recoverin and liberated by Ca2+ binding. The hydrophobic acyl moiety of recoverin may interact with the membrane only when recoverin binds Ca2+.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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1,2-Dipalmitoylphosphatidylcholine
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Acylation
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Animals
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Antigens, Neoplasm / isolation & purification
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Antigens, Neoplasm / metabolism*
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Calcium / metabolism*
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Calcium / pharmacology
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Calcium-Binding Proteins / isolation & purification
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Calcium-Binding Proteins / metabolism*
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Cattle
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Cell Membrane / metabolism
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Egtazic Acid / pharmacology
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Electrophoresis, Polyacrylamide Gel
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Eye Proteins*
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Hippocalcin
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Kinetics
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Lipoproteins*
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Liposomes
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Membrane Proteins / isolation & purification
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Membrane Proteins / metabolism*
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Molecular Weight
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Myristic Acid
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Myristic Acids / metabolism*
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Nerve Tissue Proteins*
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Peptide Fragments / isolation & purification
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Phosphatidylserines
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Protein Binding
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Recoverin
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Rod Cell Outer Segment / metabolism*
Substances
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Antigens, Neoplasm
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Calcium-Binding Proteins
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Eye Proteins
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Lipoproteins
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Liposomes
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Membrane Proteins
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Myristic Acids
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Nerve Tissue Proteins
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Peptide Fragments
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Phosphatidylserines
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Myristic Acid
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Recoverin
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Hippocalcin
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1,2-Dipalmitoylphosphatidylcholine
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Egtazic Acid
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Calcium