Structure and membrane-targeting mechanism of retinal Ca2+-binding proteins, recoverin and GCAP-2.
Recoverin and the guanylate cyclase activating proteins (GCAPs) are calcium-sensing proteins in retinal rod and cone cells that belong to the EF-hand superfamily and serve as important calcium sensors in vision. Recoverin and the OCAP proteins are myristoylated at their amino-terminus and are targeted to retinal disc membranes by a myristoyl switch. Here, we present the three-dimensional, atomic-resolution structures of recombinant myristoylated recoverin containing 0, 1 and 2 calcium ions (Ca2+) bound and unmyristoylated GCAP-2 with 3 Ca2+ bound as determined by nuclear magnetic resonance. The Ca2+-induced structural changes in these proteins are important for elucidating their membrane-targeting mechanisms and for understanding the molecular mechanism of Ca2+-sensitive regulation of phototransduction.
Ames
James B
JB
Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA. james@carb.nist.gov
Ikura
Mitsuhiko
M
D000495:Allosteric Site; D000595:Amino Acid Sequence; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000737:chemistry / Q000378:metabolism* / Q000502:physiology*; D002417:Cattle; D005136:Eye Proteins; D051604:Guanylate Cyclase-Activating Proteins; D051597:Hippocalcin; D006801:Humans; D008074:Lipoproteins; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D009419:Nerve Tissue Proteins; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000737:chemistry; D051603:Recoverin; D012160:Retina / Q000378:metabolism*
D002135:Calcium-Binding Proteins; D005136:Eye Proteins; C496739:GUCA1B protein, human; D051604:Guanylate Cyclase-Activating Proteins; D008074:Lipoproteins; D009419:Nerve Tissue Proteins; C496731:RCVRN protein, human; D011994:Recombinant Proteins; D051603:Recoverin; D051597:Hippocalcin; D002118:Calcium