Sandbox 213: Difference between revisions

The calmodulin structure has been determined by NMR. This method reveals that calmodulin is a long molecule which looks like a '''dumbbell''' because it contains '''two globular domains''' (the <scene name='Sandbox_213/N-lobe/1'>N-lobe</scene> and the <scene name='Sandbox_213/C-lobe/1'>C-lobe</scene>) linked by a <scene name='Sandbox_213/flexible α-helix/1'>flexible α-helix</scene> <ref name="Najl V Valeyev1, Declan G Bates1, Pat Heslop-Harrison1,2, Ian Postlethwaite1 and Nikolay V Kotov. Elucidating the mechanisms of cooperative calcium-calmodulin interactions: a structural systems biology approach.BMC Systems Biology 2008, 2:48 doi:[[10.1186/1752-0509-2-48]]"/>.

Each lobe contains a pair of <scene name='Sandbox_213/helix-loop-helix/1'>helix-loop-helix</scene> motifs (called EF-hand or calmodulin-fold) that can bind two Ca²⁺ ions. However those lobes do not have the same properties because the C-lobe has higher Ca²⁺ affinity than the N-lobe.  

When the Ca²⁺ concentration falls, calcium dissociates and calmodulin is quickly released, inactivating the target. However, at least one important target protein is an exception to this rule. This is CaM-kinase II which can retain its active state after it has been activated by calmodulin.

=CaMII kinase=