[{"from": "human", "value": "Describe this molecule. [C][C@H1][Branch2][Ring1][N][C@H1][Branch2][Ring1][#Branch1][C][=C][N][=C][C][=Branch1][Ring2][=N][Ring1][=Branch1][C][=Branch1][C][=O][N][C][=Branch1][Ring2][=N][Ring1][Branch2][N][O][O]"}, {"from": "gpt", "value": "The molecule is a biopterin in which the 1,2-dihydroxypropyl group has (1S,2R)-configuration. It is an enantiomer of a L-erythro-biopterin."}]