Using C[C@H](NC(=O)CN)C(=O)N[C@H](C)C(=O)NCC(=O)NCC(=O)O to produce C[C@@H]1NC(=O)CNC(=O)CNC(=O)CNC(=O)[C@@H](C)NC1=O, please predict the agent for this reaction in SMILES notation in \boxed{$SMILES1, SMILES2, ...} format.