The molecule is a zwitterion derived from (beta-Asp-Arg)n. Major microspecies at pH 7.3. It is a tautomer of a cyanophycin macromolecule.
(2S)-2-[[(3S)-3-azaniumyl-4-[[(2S)-1-[[(1S)-1-carboxylato-3-[[(1S)-1-carboxylato-4-(diaminomethylideneazaniumyl)butyl]amino]-3-oxopropyl]amino]-4-[[(1S)-1-carboxylato-4-(diaminomethylideneazaniumyl)butyl]amino]-1,4-dioxobutan-2-yl]amino]-4-oxobutanoyl]amino]-5-(diaminomethylideneazaniumyl)pentanoate