Graphic Representations of Ras protein:

   Ras is a G-protein (binds GTP) linked to
   plasma membrane by a lipid anchor.

   Activation of Ras is induced by ligand
   binding to receptor tryrosine kinases.

   The inactive GDP-bound form is shown.
       a) alpha carbon trace
       b) shows all atoms in molecule
       c) shows a  helicies &  β sheets
       d) water accessible surface contour
               positive charge area = blue
               negative charge areas = red