Sandbox Reserved 702: Difference between revisions

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The helical domain of the edema factor interacts with the adenylyl cyclase domain and switch C in the absence of calmodulin. This locks the enzyme in an inactive state. The binding of calmodulin on four discrete regions dicrupts most of those interaction allowing the enzyme to switch in an active form. This takes place in two steps.

The calcium-free, closed N-terminal domain of calmodulin binds to the edema factor thanks to an interaction with its helical domain. This interaction is due to hydrogen bonds and a salt bridge between helices I and II of the N-terminal domain of calmodulin and helices L and M of the helical domain of the edema factor. When the N-terminal domain is noud to the helical domain, the calcium-loaded C-terminal domain in its open conformation inserts between the helical domain and the catalytic core. This allows a conformational change of switch C that will stabilize the catalytic loop (switch B) of the enzyme in an active state. A rigid-body rotation of CB relative to CA also occurs. This changes the pocket formed between these two domains and allows the interaction of the edema factor with the phospates of ATP.

The calcium-free, closed N-terminal domain of calmodulin binds to the edema factor thanks to an interaction with its helical domain. This interaction is due to hydrogen bonds and a salt bridge between helices I and II of the N-terminal domain of calmodulin and helices L and M of the helical domain of the edema factor. When the N-terminal domain is noud to the helical domain, the calcium-loaded C-terminal domain in its open conformation inserts between the helical domain and the catalytic core. This allows a conformational change of switch C that will stabilize the catalytic loop (switch B) of the enzyme in an active state. A rigid-body rotation of CB relative to CA also occurs. This changes the pocket formed between these two domains and allows the interaction of the edema factor with the phospates of ATP. Indeed, the edema factor helical domain undergoes a 15 Å translation and a 30° rotation away from the catalytic core and stabilizes the disordered loop.

=== Two magnesium ions are coordinated by the catamytic site ===

Sandbox Reserved 702: Difference between revisions

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 The helical domain of the edema factor interacts with the adenylyl cyclase domain and switch C in the absence of calmodulin. This locks the enzyme in an inactive state. The binding of calmodulin on four discrete regions dicrupts most of those interaction allowing the enzyme to switch in an active form. This takes place in two steps.
-The calcium-free, closed N-terminal domain of calmodulin binds to the edema factor thanks to an interaction with its helical domain. This interaction is due to hydrogen bonds and a salt bridge between helices I and II of the N-terminal domain of calmodulin and helices L and M of the helical domain of the edema factor. When the N-terminal domain is noud to the helical domain, the calcium-loaded C-terminal domain in its open conformation inserts between the helical domain and the catalytic core. This allows a conformational change of switch C that will stabilize the catalytic loop (switch B) of the enzyme in an active state. A rigid-body rotation of CB relative to CA also occurs. This changes the pocket formed between these two domains and allows the interaction of the edema factor with the phospates of ATP.
+The calcium-free, closed N-terminal domain of calmodulin binds to the edema factor thanks to an interaction with its helical domain. This interaction is due to hydrogen bonds and a salt bridge between helices I and II of the N-terminal domain of calmodulin and helices L and M of the helical domain of the edema factor. When the N-terminal domain is noud to the helical domain, the calcium-loaded C-terminal domain in its open conformation inserts between the helical domain and the catalytic core. This allows a conformational change of switch C that will stabilize the catalytic loop (switch B) of the enzyme in an active state. A rigid-body rotation of CB relative to CA also occurs. This changes the pocket formed between these two domains and allows the interaction of the edema factor with the phospates of ATP. Indeed, the edema factor helical domain undergoes a 15 Å translation and a 30° rotation away from the catalytic core and stabilizes the disordered loop.
+=== Two magnesium ions are coordinated by the catamytic site ===