 However, unlike those in the Ras superfamily, conformational change when shuttling between forms only affects switch I, while switch II remains relatively stable, due to difference in secondary structure.Ras switch II forms a long α-helical structure between shuttling, while RHEB switch II adopts a more atypical conformation allowing for novel functions.Such a conformation causes a decreased intrinsic rate of GTP hydrolysis as compared to RAS due to the catalytic Asp65 in the switch II region of RHEB being blocked from the active site.