The molecule is an L-alpha-amino acid zwitterion formed from hercynylcysteine sulfoxide by transfer of a proton from the carboxy to the amino group; major species at pH 7.3. It is a tautomer of a hercynylcysteine sulfoxide.
(2S)-3-[2-[(2R)-2-azaniumyl-2-carboxylatoethyl]sulfinyl-1H-imidazol-5-yl]-2-(trimethylazaniumyl)propanoate