The molecule is a linear tetrapyrrole anion obtained by deprotonation of the two carboxy groups of mycobilin b; major species at pH 7.3. It is a dicarboxylic acid dianion and a linear tetrapyrrole anion. It is a conjugate base of a mycobilin b.
3-[(2Z,5Z)-2-[[3-(2-carboxylatoethyl)-5-(4-ethenyl-5-formyl-3-methyl-1H-pyrrole-2-carbonyl)-4-methyl-1H-pyrrol-2-yl]methylidene]-5-[(3-ethenyl-4-methyl-5-oxopyrrol-2-yl)methylidene]-4-methylpyrrol-3-yl]propanoate