▁position ▁ 1 0 7 ▁to ▁L ys - 1 0 7 ▁completely ▁abol ishes ▁transform ing ▁activity . ▁De le ter ious ▁mut ations ▁within ▁this ▁segment ▁( am ino ▁acid ▁positions ▁ 1 0 5 ▁to ▁ 1 1 4 , ▁inclus ive ) ▁also ▁imp air ▁binding ▁of ▁the ▁mut ant ▁T Ag ▁protein ▁species ▁to ▁p R b , ▁imp lying ▁a ▁correlation ▁between ▁transform ing ▁activity ▁and ▁the ▁ability ▁of ▁T Ag ▁to ▁bind ▁p R b . ▁ ▁A ▁detailed ▁computer ized ▁bio in format ics ▁analysis , ▁as ▁well ▁as ▁an ▁x - ray ▁cry stal log raph y ▁study , ▁have ▁demonstrated ▁the ▁bi oph ys ical ▁basis ▁for ▁the ▁interaction ▁between ▁this ▁region ▁of ▁T Ag ▁and ▁p R b . ▁T Ag ▁resid ues ▁ 1 0 3 ▁to ▁ 1 0 9 ▁form ▁an ▁extended ▁loop ▁structure ▁that ▁bind s ▁tight ly ▁in ▁a ▁surface ▁gro ove ▁of ▁p R b . ▁In ▁the ▁cry stal ▁structure , ▁Le u - 1 0 3 ▁is ▁position ed ▁so ▁that ▁it ▁makes ▁van ▁der ▁Wa als ▁contacts ▁with ▁the ▁hydro ph ob ic ▁side ▁ch ains ▁of ▁Val - 7 1 4 ▁and ▁Le u - 7 6 9 ▁in ▁p R b . ▁A ▁number ▁of ▁hydro gen ▁b onds ▁also ▁stabil ize ▁the ▁T Ag – p R b ▁complex . ▁For ▁example , ▁the ▁side ▁chain ▁of ▁G lu - 1 0 7 ▁forms ▁hydro gen ▁b onds ▁by ▁accepting