Calcium-free Calmodulin: Difference between revisions
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Calmodulin is a molecule that has been studied extensively in its functions within the cell, and has an important role in relaying Ca2+ signals within the cytosol. <ref name="1CRT">Hoeflich, K.P., & Ikura, M.. Calmodulin in action: diversity in target recognition and activation mechanisms, Cell. 2002 108:739-742</ref> It does this by binding to Ca2+, undergoing a conformational change, and may interact with various proteins within the cell.<ref name="1CRT"/><ref name="4CRT">PMID: 7552748</ref><ref name="3CRT">PMID: 3145979</ref> Once bound to a target protein, it undergoes a further conformational change and may activate certain systems. For example, there is a Ca2+ pump in the plasma membrane pump that is activated by the binding of Ca2+-bound calmodulin, and then uses ATP to drive the Ca2+ out of the cell. <ref name="6CRT">PMID: 12838335</ref> | Calmodulin is a molecule that has been studied extensively in its functions within the cell, and has an important role in relaying Ca2+ signals within the cytosol. <ref name="1CRT">Hoeflich, K.P., & Ikura, M.. Calmodulin in action: diversity in target recognition and activation mechanisms, Cell. 2002 108:739-742</ref> It does this by binding to Ca2+, undergoing a conformational change, and may interact with various proteins within the cell.<ref name="1CRT"/><ref name="4CRT">PMID: 7552748</ref><ref name="3CRT">PMID: 3145979</ref> Once bound to a target protein, it undergoes a further conformational change and may activate certain systems. For example, there is a Ca2+ pump in the plasma membrane pump that is activated by the binding of Ca2+-bound calmodulin, and then uses ATP to drive the Ca2+ out of the cell. <ref name="6CRT">PMID: 12838335</ref> | ||
=='''Calcium-bound Calmodulin'''== | |||
[[Image:3cln.png|left|200px]] | [[Image:3cln.png|left|200px]] | ||
The structure of calcium-bound calmodulin had previously been discovered using x-ray crystallography <ref name="3CRT"/> | The structure of calcium-bound calmodulin had previously been discovered using x-ray crystallography. <ref name="3CRT"/> It was then theorized that knowledge of the structure of calcium-free calmodulin would give greater insight into the function of the protein. Attempts were made to crystallize the calcium-free (or apo) form, but to no avail, thus it was decided that the only way to get a good idea of the structure would be to use several NMR experiments. <ref name="4CRT"/> | ||
=='''Calcium-free Calmodulin'''== | |||
[[Image:calmodulin.png|right|200px]] | |||
The structure of calcium-free calmodulin was discovered by doing several different NMR experiments that included ROE, reverse labelling of Phe residues, and 3-bond J-couplings. <ref name="4CRT"/> It was theorized that by comparing the results of the NMR experiments for the apo calmodulin with the calcium-bound calmodulin, information could be gleaned as to the structural changes that occur when calcium is bound. It was discovered that the series of residues | |||
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==References== | ==References== | ||
<references/> | <references/> | ||
