(a) The S1, P1 and P4 binding pockets in 1BKD are predicted using the IChem package. The inset shows the small molecules bound at S1, P1 and P4 in the crystal strucutres 4UR4, 4URZ and 4US0, respectively. The plots (b)-(d) show all the binding sites of the CDC25 domains, the catalytic HRas, the REM domains and the allosteric HRAS in the tertariy complexes, respectively. The REM domains have the R1 binding sites. The allesteric HRAS have the P1 and P4 sites similar to the catalytic HRas.