Role of the acylated amino terminus of recoverin in Ca(2+)-dependent membrane interaction.
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+.
Dizhoor
A M
AM
Department of Biochemistry, University of Washington, Seattle 98195.
Chen
C K
CK
Olshevskaya
E
E
Sinelnikova
V V
VV
Phillipov
P
P
Hurley
J B
JB
D015060:1,2-Dipalmitoylphosphatidylcholine; D000215:Acylation; D000818:Animals; D000951:Antigens, Neoplasm / Q000302:isolation & purification / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism* / Q000494:pharmacology; D002135:Calcium-Binding Proteins / Q000302:isolation & purification / Q000378:metabolism*; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D004591:Electrophoresis, Polyacrylamide Gel; D005136:Eye Proteins; D051597:Hippocalcin; D007700:Kinetics; D008074:Lipoproteins; D008081:Liposomes; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D019814:Myristic Acid; D009227:Myristic Acids / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments / Q000302:isolation & purification; D010718:Phosphatidylserines; D011485:Protein Binding; D051603:Recoverin; D012374:Rod Cell Outer Segment / Q000378:metabolism*
D000951:Antigens, Neoplasm; D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D008081:Liposomes; D008565:Membrane Proteins; D009227:Myristic Acids; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010718:Phosphatidylserines; D019814:Myristic Acid; D051603:Recoverin; D051597:Hippocalcin; D015060:1,2-Dipalmitoylphosphatidylcholine; D004533:Egtazic Acid; D002118:Calcium