Sandbox 213: Difference between revisions
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Calmodulin contains four Ca2+ binding sites and the binding of calcium induces a conformational change in calmodulin that can cause the activation of key enzymes such as kinases or phosphatases proteins (especially phosphorylase kinases) which are not necessarily themselves Ca2+-sensitive and allows a large diversity of cellular response. | Calmodulin contains four Ca2+ binding sites and the binding of calcium induces a conformational change in calmodulin that can cause the activation of key enzymes such as kinases or phosphatases proteins (especially phosphorylase kinases) which are not necessarily themselves Ca2+-sensitive and allows a large diversity of cellular response. | ||
=Calmodulin structure= | |||
Calmodulin is able to bind a large range of target molecules. This property is due to its particularly flexible structure that confers the capacity to change its conformation according to the concentration of calcium in the cell. The calmodulin structure has been determined by RMN. This method reveals that calmodulin is a long molecule which looks like a dumbbell because it contains two globular domains (the N-lobe and the C-lobe) linked by a flexible α-helix. Each lobe contains a pair of helix-loop-helix motifs (called EF-hand) 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. The two EF-hands are located in the vicinity of each other. Those neighboring sited are very likely to structurally influence each other upon Ca2+ binding to one of them. | Calmodulin is able to bind a large range of target molecules. This property is due to its particularly flexible structure that confers the capacity to change its conformation according to the concentration of calcium in the cell. The calmodulin structure has been determined by RMN. This method reveals that calmodulin is a long molecule which looks like a dumbbell because it contains two globular domains (the N-lobe and the C-lobe) linked by a flexible α-helix. Each lobe contains a pair of helix-loop-helix motifs (called EF-hand) 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. The two EF-hands are located in the vicinity of each other. Those neighboring sited are very likely to structurally influence each other upon Ca2+ binding to one of them. | ||
