Catalytic subunit of cyclic AMP-dependent protein kinase: structure and dynamics of the active site cleft.

The catalytic subunit of cyclic AMP-dependent protein kinase serves as a structural template for the entire family of Ser, Thr, and Tyr specific protein kinases. We review here the dynamics of the active catalytic subunit. These dynamics correlate with an opening and closing of the active site cleft, and are considered to be a requirement for catalysis. The motions, described by a set of several crystal structures, reveal a very fluid active site cleft. This active site cleft with its dynamic opening and closing is a prime target for protein kinase inhibitors.