Structural Basis for Calcium-induced Inhibition of Rhodopsin Kinase by Recoverin.
From: Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, Maryland 20850, USA. ames@chem.ucdavis.edu
The Journal of biological chemistry
- Publish Date: Dec 2006
- ISSN: 0021-9258
- Volume: 281
- Issue: 48
- Pages: 37237-45
- Medium: Print
- Language: English
- Citation (JAMA): Ames James B, Levay Konstantin, Wingard Jennifer N, et al. Structural Basis for Calcium-induced Inhibition of Rhodopsin Kinase by Recoverin.. J. Biol. Chem. Dec 2006;281:37237-45
Abstract
Recoverin, a member of the neuronal calcium sensor branch of the EF-hand superfamily, serves as a calcium sensor that regulates rhodopsin kinase (RK) activity in retinal rod cells. We report here the NMR structure of Ca(2+)-bound recoverin bound to a functional N-terminal fragment of rhodopsin kinase (residues 1-25, called RK25). The overall main-chain structure of recoverin in the complex is similar to structures of Ca(2+)-bound recoverin in the absence of target (<1.8A root-mean-square deviation). The first eight residues of recoverin at the N terminus are solvent-exposed, enabling the N-terminal myristoyl group to interact with target membranes, and Ca(2+) is bound at the second and third EF-hands of the protein. RK25 in the complex forms an amphipathic helix (residues 4-16). The hydrophobic face of the RK25 helix (Val-9, Val-10, Ala-11, Ala-14, and Phe-15) interacts with an exposed hydrophobic groove on the surface of recoverin lined by side-chain atoms of Trp-31, Phe-35, Phe-49, Ile-52, Tyr-53, Phe-56, Phe-57, Tyr-86, and Leu-90. Residues of recoverin that contact RK25 are highly conserved, suggesting a similar target binding site structure in all neuronal calcium sensor proteins. Site-specific mutagenesis and deletion analysis confirm that the hydrophobic residues at the interface are necessary and sufficient for binding. The recoverin-RK25 complex exhibits Ca(2+)-induced binding to rhodopsin immobilized on concanavalin-A resin. We propose that Ca(2+)-bound recoverin is bound between rhodopsin and RK in a ternary complex on rod outer segment disk membranes, thereby blocking RK interaction with rhodopsin at high Ca(2+).
Mesh Headings (Keywords): Amino Acid Sequence, Animals, Binding Sites, Calcium, Cattle, Crystallography, X-Ray, Dose-Response Relationship, Drug, G-Protein-Coupled Receptor Kinase 1, Magnetic Resonance Spectroscopy, Molecular Conformation, Molecular Sequence Data, Mutagenesis, Site-Directed, Neurons, Protein Binding, Recoverin, Rhodopsin
Check for Full Text / PubMed Unique Identifier (PMID): 17020884
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