Subdomain III of Kinase Domain of Protein Kinase A

Subdomain III consists of a large alpha helix, in the small lobe of PKA, and is shown by the peach ribbon structure. It contains an invariant residue in Glu91. Glu91 is located in the middle of the helix and helps to stabilize the interactions between Lys72 and the alpha and beta phosphates of MgATP