BIO315H5 Study Guide - Midterm Guide: Protein Kinase, Dynamic Equilibrium, Allosteric Regulation
Document Summary
Undergoes a conformational change when bound allosterically to calcium. Regulatory segment at active site of kinase blocks kinase activity & regulated by calmodulin. Each has 2 major domains: amino-terminal kinase (green) and carboxyl-terminal hub (blue) 6 camkii proteins are assembled surrounded by kinase domains. When the enzyme is inactive, the ring exists in a dynamic equilibrium between two states. Compact state kinase domains interact with hub, regulatory segment is buried in kinase active site and thereby blocks catalytic activity. Inactive state kinase domain has popped out and is linked to central hub by its regulatory segment, which continues to inhibit the kinase but is now accessible to ca2+/calmodulin. If present, ca2+/calmodulin will bind the regulatory segment and prevent it from inhibiting the kinase, thereby locking the kinase in an active state. If the adjacent kinase subunit also pops out from the hub, it will also be activated by.
