ONH(S)NHNONH(S)NHONH(S)HOONH(S)OHONH(R)OONH(S)CH3CH3ONH(R)OONH(S)NHNHNH2ON(S)NH-NHtBuNHNHHisTrpSerTyrD-SerLeuArgProO(R)NHOHCH3H3CCH3NH2ONH2O