[{"from": "human", "value": "Describe this molecule. [C][C][=C][Branch2][=Branch1][Branch2][C][=C][C@@H1][Branch2][Branch1][S][C][N][Branch2][Ring1][=C][C][Ring1][Branch1][=C][C][=Branch1][#Branch1][=C][Ring1][=Branch2][N][Ring1][N][O][C][=Branch1][C][=O][N][C][C][N][Branch1][Branch1][C][C][Ring1][=Branch1][C][C][=Branch1][C][=O][C][=C][C][=C][C][=Branch1][P][=C][Branch1][N][C][=Branch1][#Branch1][=C][Ring1][=Branch1][N][Ring1][=Branch2][O][C][O][C][O][C][C][Br][C][=Branch1][C][=O][O][C]"}, {"from": "gpt", "value": "The molecule is a semisynthetic water-soluble derivative of the antineoplastic antibiotic duocarmycin B2.  Activated by carboxyl esterase, pibrozelesin alkylates DNA by binding to adenine-thymine (A-T)-rich sequences in the minor groove of DNA, thereby inhibiting DNA replication and inducing apoptosis."}]