Recoverin, a calcium-activated myristoyl switch: Difference between revisions
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==Myristoyl Switch and Calcium== | ==Myristoyl Switch and Calcium== | ||
Recoverin has a<scene name='Recoverin,_a_calcium-activated_myristoyl_switch/Recoverin_morph/3' myristic acid</scene> (14-carbon saturated fatty acid, or a similar acyl moiety) covalently linked via an amide bond to its N-terminal glycine. In the absence of calcium, the myristoyl group is buried in the N-terminal protein domain, surrounded on all sides by alpha helices that form a hydrophobic pocket. The binding of two calcium ions to each recoverin molecule induces a <scene name='Recoverin,_a_calcium-activated_myristoyl_switch/Recoverin_morph/1'>conformational change </scene> that extrudes the myristoyl and exposes some hydrophobic amino acids on the surface. This enables the molecule to bind to the lipid bilayers of the disc membranes. | Recoverin has a<scene name='Recoverin,_a_calcium-activated_myristoyl_switch/Recoverin_morph/3'>myristic acid</scene> (14-carbon saturated fatty acid, or a similar acyl moiety) covalently linked via an amide bond to its N-terminal glycine. In the absence of calcium, the myristoyl group is buried in the N-terminal protein domain, surrounded on all sides by alpha helices that form a hydrophobic pocket. The binding of two calcium ions to each recoverin molecule induces a <scene name='Recoverin,_a_calcium-activated_myristoyl_switch/Recoverin_morph/1'>conformational change </scene> that extrudes the myristoyl and exposes some hydrophobic amino acids on the surface. This enables the molecule to bind to the lipid bilayers of the disc membranes. | ||
The two calcium ions each bind to an EF hand motif, one in the C-terminal domain, and one in the N-terminal domain. Recoverin actually contains four EF hand motifs, but two of them are unable to bind calcium due to variations in sequence. | The two calcium ions each bind to an EF hand motif, one in the C-terminal domain, and one in the N-terminal domain. Recoverin actually contains four EF hand motifs, but two of them are unable to bind calcium due to variations in sequence. | ||