title: Sequestration of the membrane-targeting myristoyl group of recoverin in the calcium-free state.
abstract: Recoverin, a retinal calcium-binding protein of relative molecular mass (M(r)) 23K, participates in the recovery phase of visual excitation and in adaptation to background light. The Ca(2+)-bound form of recoverin prolongs the photoresponse, probably by blocking phosphorylation of photoexcited rhodopsin. Retinal recoverin contains a covalently attached myristoyl group or related acyl group at its amino terminus and two Ca(2+)-binding sites. Ca2+ binding to myristoylated, but not unmyristoylated, recoverin induces its translocation to bilayer membranes, indicating that the myristoyl group is essential to the read-out of calcium signals (calcium-myristoyl switch). Here we present the solution structure of Ca(2+)-free, myristoylated recombinant recoverin obtained by heteronuclear multidimensional NMR spectroscopy. The myristoyl group is sequestered in a deep hydrophobic pocket formed by many aromatic and other hydrophobic residues from five flanking helices.
authors.affiliation: Division of Molecular and Structural Biology, Ontario Cancer Institute, Toronto, Canada.
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: J B
authors.initials: JB
authors.lastname: Ames
authors.forename: T S
authors.initials: TS
authors.lastname: Harvey
authors.forename: L
authors.initials: L
authors.lastname: Stryer
authors.forename: M
authors.initials: M
authors.lastname: Ikura
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000737:chemistry; D002135:Calcium-Binding Proteins / Q000737:chemistry*; D003196:Computer Graphics; D005136:Eye Proteins; D051597:Hippocalcin; D008074:Lipoproteins; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D009227:Myristic Acids / Q000737:chemistry*; D009419:Nerve Tissue Proteins; D011487:Protein Conformation; D011994:Recombinant Proteins / Q000737:chemistry; D051603:Recoverin; D017386:Sequence Homology, Amino Acid; D012996:Solutions
chemical_list: D002135:Calcium-Binding Proteins; D005136:Eye Proteins; D008074:Lipoproteins; D009227:Myristic Acids; D009419:Nerve Tissue Proteins; D011994:Recombinant Proteins; D012996:Solutions; D051603:Recoverin; D051597:Hippocalcin; D002118:Calcium