[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is a monocarboxylic acid anion that is the conjugate base of 5-oxo-4,5-dihydro-2-furylacetic acid. It has a role as a bacterial metabolite. It is a conjugate base of a 5-oxo-4,5-dihydro-2-furylacetic acid."}, {"from": "gpt", "value": "[C][C][=C][Branch1][=Branch1][O][C][Ring1][Branch1][=O][C][C][=Branch1][C][=O][O-1]"}]