[{"from": "human", "value": "Generate a molecule based on the given description. The molecule is conjugate base of 5-methylthio-2-oxopentanoic acid. It is a conjugate base of a 5-methylthio-2-oxopentanoic acid."}, {"from": "gpt", "value": "[C][S][C][C][C][C][=Branch1][C][=O][C][=Branch1][C][=O][O-1]"}]