Sandbox 213: Difference between revisions
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Calmodulin uses a linear sequence of 12 amino acids to bind Ca<sup>2+</sup>. | Calmodulin uses a linear sequence of 12 amino acids to bind Ca<sup>2+</sup>. | ||
Binding of Ca<sup>2+</sup> to the four sites induces a large conformational change causing the terminal helices to expose hydrophobic surfaces and also a long central α-helical segment. Ca<sup>2+</sup>-bound calmodulin binds to its targets with high affinity (K<sub>D</sub>≈10<sup>−9</sup> mol.L<sup>−1</sup>)<ref name=" | Binding of Ca<sup>2+</sup> to the four sites induces a large conformational change causing the terminal helices to expose hydrophobic surfaces and also a long central α-helical segment. Ca<sup>2+</sup>-bound calmodulin binds to its targets with high affinity (K<sub>D</sub>≈10<sup>−9</sup> mol.L<sup>−1</sup>)<ref name="Fallon JL, Quiocho FA. A closed compact structure of native Ca(2+)-calmodulin. Structure. 2003 Oct;11(10):1303-7. PMID :[[14527397]]"/>. | ||
]]"/>. | |||
*'''Calmodulin bound to a target peptide''' | *'''Calmodulin bound to a target peptide''' | ||
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The N-terminal and C-terminal regions approach each other and by their hydrophobic surfaces bind to it, rather like two hands holding a rope. | The N-terminal and C-terminal regions approach each other and by their hydrophobic surfaces bind to it, rather like two hands holding a rope. | ||
This encourages the target sequence to adopt an α-helical arrangement so that it occupies the center of a hydrophobic tunnel. | This encourages the target sequence to adopt an α-helical arrangement so that it occupies the center of a hydrophobic tunnel. | ||
The consequence of this interaction is a conformational change in the target, a state that persists only as long as the Ca<sup>2+</sup> concentration remains high <ref name=" | The consequence of this interaction is a conformational change in the target, a state that persists only as long as the Ca<sup>2+</sup> concentration remains high <ref name="Fallon JL, Quiocho FA. A closed compact structure of native Ca(2+)-calmodulin. Structure. 2003 Oct;11(10):1303-7. PMID :[[14527397]]"/>. | ||
