What is the Most Appropriate Enzyme Form for Crystallography

2 What is the Most Appropriate Enzyme Form for Crystallography  

The most pervasive mechanism for the regulation of kinases is that effected by other kinases and phosphatases that add and remove phosphate at multiple sites. Another common mechanism by which kinase activity and substrate binding (ATP and acceptor protein) are regulated is through the binding to proteins that 

Recent Abl structural studies comparing the binding of 1 to PD 173955, 25, suggest that for this example the unique binding conformation may come at a high cost [26]. PD 173955, which has a reduced contact surface with the enzyme, does not bind in the pocket formed by movement of the activation loop. However, 

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