Figure 2.

Structure of the dimeric MRCKβ catalytic domain. The dimeric MRCKβ is based on the coordinates in 3TKU. The catalytic domain reveals a typical structure, with the disposition of C- and N-lobe as indicated. The activation loop (purple) is fully ordered, and the aC-helix (yellow) lies in a position that would be compatible with catalysis. The position of ATP as indicated is based on binding of Fasudil in this crystal structure.⁴⁰ The hydrophobic motif (dark blue) binds to the N-lobe as is typical for other kinases, but this region makes substantial contacts also with the N-terminal helices that are involved in dimerization. Thus the dimerization domain may be required for holding the hydrophobic motif.