The molecule is dicarboxylate anion of (3Z)-phytochromobilin. It is a linear tetrapyrrole anion and a dicarboxylic acid dianion. It is a conjugate base of a (3Z)-phytochromobilin.
3-[(2Z,5Z)-2-[[3-(2-carboxylatoethyl)-5-[(Z)-[(3Z,4R)-3-ethylidene-4-methyl-5-oxopyrrolidin-2-ylidene]methyl]-4-methyl-1H-pyrrol-2-yl]methylidene]-5-[(4-ethenyl-3-methyl-5-oxopyrrol-2-yl)methylidene]-4-methylpyrrol-3-yl]propanoate