Characterization of rhodopsin kinase purified from bovine rod outer segments
Department of Biochemistry
Amino Acid Sequence; Animals; Cattle; Chromatography, Ion Exchange; Electrophoresis, Polyacrylamide Gel; *Eye Proteins; G-Protein-Coupled Receptor Kinase 1; Kinetics; Molecular Sequence Data; Peptides; Phosphorylation; Photoreceptors; Protein Kinases; Rod Outer Segments; Substrate Specificity
Life Sciences | Medicine and Health Sciences
Rhodopsin kinase was purified by sequential chromatography on DEAE-cellulose and blue-Sepharose. Kinase activity co-purified with a 62-kDa polypeptide, which bound light-dependently in the absence of ATP to purified vesicle-reconstituted rhodopsin. Purified rhodopsin kinase is free of any detectable arrestin or the retinal G-protein. Rhodopsin kinase is autophosphorylated on serine residues which is unaffected by the presence of bleached rhodopsin and results in a transition in molecular mass to 64 kDa. Autophosphorylation of the kinase did not appear to alter the overall rate of rhodopsin phosphorylation or the apparent KM (0.6 microM) for purified reconstituted rhodopsin. Peptides corresponding to sequences within opsin loops 3-4 and 5-6 and the COOH terminus inhibited kinase phosphorylation of bleached rhodopsin, suggesting at least three potential sites to account for the stable high affinity binding of rhodopsin kinase to the bleached photoreceptor molecule that are at least in part distinct from the substrate sites for phosphorylation. These sequences are similar to those proposed for receptor recognition of G-proteins and indicate that the domains involved in light-dependent binding of rhodopsin kinase and retinal G-protein are similar or overlapping.
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Citation: J Biol Chem. 1990 Feb 15;265(5):2632-9.
The Journal of biological chemistry
Kelleher, Daniel J. and Johnson, Gary L., "Characterization of rhodopsin kinase purified from bovine rod outer segments" (1990). Open Access Articles. 871.