▁or ▁thre on ine ▁resid ues ▁under going ▁anti ▁elim ination ▁of ▁water , ▁th ia z oles ▁from ▁c yst e ine ▁resid ues ▁with ▁cycl ode h yd r ation ▁followed ▁by ▁de ox y gen ation , ▁and ▁the ▁central ▁hydro x yp y rid ine ▁produced ▁by ▁cycl ization ▁between ▁two ▁de h ydro al an ine ▁ac ids ▁with ▁incorpor ation ▁of ▁an ▁adjacent ▁car b ony l ▁group . ▁ ▁N osi he pt ide ▁b ios yn thesis ▁begins ▁with ▁the ▁translation ▁of ▁a ▁ 5 0 ▁am ino ▁acid ▁prec ursor ▁pe pt ide ▁consisting ▁of ▁a ▁ 3 7 ▁am ino ▁acid ▁leader ▁pe pt ide ▁f used ▁to ▁a ▁ 1 3 ▁am ino ▁acid ▁struct ural ▁pe pt ide ▁( S CT T CE CC C SC SS ), ▁matching ▁the ▁nos ihe pt ide ▁back bone ▁aside ▁from ▁the ▁C - term inal ▁ser ine ▁resid ue ▁that ▁is ▁partially ▁cle aved ▁in ▁m atur ation ▁of ▁the ▁final ▁product . ▁Next , ▁cycl izations ▁occur ▁between ▁ 5 ▁of ▁the ▁c yst e ine ▁resid ues ▁in ▁the ▁struct ural ▁sequence ▁and ▁the ▁previous ▁car b ony l ▁on ▁the ▁adjacent ▁am ino ▁acid ▁to ▁form ▁th ia z ole ▁rings ▁after ▁ox id ation . ▁Several ▁am ino ▁acid ▁resid ues ▁then ▁under go ▁elim ination ▁of ▁water ▁to ▁produce ▁de h ydro am ino ▁ac ids , ▁and ▁the ▁first ▁macro cycle ▁is ▁constructed ▁by ▁cycl ization ▁of