2i94
NMR Structure of recoverin bound to rhodopsin kinase
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OverviewOverview
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+).
About this StructureAbout this Structure
2I94 is a Protein complex structure of sequences from Bos taurus with CA as ligand. Active as Rhodopsin kinase, with EC number 2.7.11.14 Full crystallographic information is available from OCA.
ReferenceReference
Structural basis for calcium-induced inhibition of rhodopsin kinase by recoverin., Ames JB, Levay K, Wingard JN, Lusin JD, Slepak VZ, J Biol Chem. 2006 Dec 1;281(48):37237-45. Epub 2006 Oct 4. PMID:17020884
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