[{"from": "human", "value": "Design a molecule that meets the criteria outlined in the description. The molecule is an alpha-amino acid zwitterion obtained by transfer of a proton from the carboxy to the amino group of D-isoleucine; major species at pH 7.3. It is a tautomer of a D-isoleucine."}, {"from": "gpt", "value": "[C][C][C@@H1][Branch1][C][C][C@H1][Branch1][=Branch1][C][=Branch1][C][=O][O-1][NH3+1]"}]