Figure 3.

Structural features of CMGC protein kinases discussed in the text. The structure of p38 MAP kinase (PDB 1cm8) is shown as a prototype of the CMGC group. Color scheme is as follows: Main-chain traces of key regions, colored as indicated at the top of Figure 1 ▶; main-chain traces of other regions are light gray; ATPs are cyan; phosphate moieties use the standard CPK color scheme; oxygen, nitrogen, and hydrogen atoms establishing hydrogen bonds are red, blue, and white, respectively; side chains of kinase-shared residues are pale magenta; and CMGC-specific residues are light yellow. Hydrogen bonds are depicted as dotted lines; CH–π interactions (Weiss et al. 2001) are depicted as dotted lines into dot clouds. (A) Key regions within the protein kinase N- and C-terminal domains. The locations of the αC, αF, and αG helices are indicated. (B) Close-up of regions that stabilize and interact with the CMGC-arginine (R192). Modeled substrate with a P + 1 proline is shown.