[{"from": "human", "value": "Based on the given information, design a molecule that meets the desired specifications. The molecule is a dicarboxylic acid dianion that is the conjugate base of mesaconic acid. It has a role as a human metabolite and a plant metabolite. It is functionally related to a fumarate(2-). It is a conjugate base of a mesaconic acid."}, {"from": "gpt", "value": "[C][/C][=Branch1][#Branch1][=C][\\C][=Branch1][C][=O][O-1][/C][=Branch1][C][=O][O-1]"}]