▁N 1 ▁atom ▁while ▁the ▁G lu 1 2 1 ▁back bone ▁car b ony l ▁o xygen ▁atom ▁don ates ▁electrons ▁to ▁the ▁ATP ▁pur ine ▁ring ▁N 6 ▁atom . ▁M imet ics ▁of ▁ATP ▁like ▁bal an ol ▁can ▁be ▁anch ored ▁within ▁the ▁hydro ph ob ic ▁ad en ine - binding ▁pocket ▁because ▁their ▁plan ar ▁subst itu ents ▁can ▁make ▁favor able ▁non pol ar ▁interactions . ▁The ▁rib ose ▁sub site ▁is ▁occupied ▁by ▁bal an ol ' s ▁ax ep ane ▁ring . ▁Specifically , ▁the ▁N 1 ▁atom ▁of ▁the ▁a ze p ane ▁ring ▁hydro gen ▁b onds ▁with ▁the ▁back bone ▁car b ony l ▁o xygen ▁atom ▁of ▁G lu 1 7 0 ▁of ▁the ▁catal yt ic ▁loop . ▁At oms ▁within ▁the ▁a ze p ane ▁ring ▁also ▁can ▁make ▁favor able ▁non pol ar ▁contacts ▁with ▁resid ues ▁G ly 5 0 , ▁Fl u 1 2 7 , ▁and ▁G lu 1 7 0 . ▁While ▁other ▁interactions ▁also ▁occur , ▁most ▁of ▁the ▁polar ▁and ▁non pol ar ▁interactions ▁involve ▁the ▁ben z oph en one ▁subst itu ent ▁of ▁bal an ol , ▁which ▁interact s ▁with ▁resid ues ▁compr ising ▁the ▁ph osph ate - binding ▁sub site . ▁For ▁instance , ▁bal an ol ' s ▁ben z oph en one ▁ring ▁interact s ▁with ▁numerous ▁highly ▁conser ved ▁resid ues ▁in ▁PK A ▁such ▁as ▁G ly 5 2 , ▁P he