Chrysobactin siderophores produced by Dickeya chrysanthemi EC16.

The plant pathogen Dickeya chrysanthemi EC16 (formerly known as Petrobacterium chrysanthemi EC16 and Erwinia chrysanthemi EC16) was found to produce a new triscatecholamide siderophore, cyclic trichrysobactin, the related catecholamide compounds, linear trichrysobactin and dichrysobactin, and the previously reported monomeric siderophore unit, chrysobactin. Chrysobactin is comprised of L-serine, D-lysine, and 2,3-dihydroxybenzoic acid (DHBA). Trichrysobactin is a cyclic trimer of chrysobactin joined by a triserine lactone backbone. The chirality of the ferric complex of cyclic trichrysobactin is found to be in the Λ configuration, similar to Fe(III)-bacillibactin, which contains a glycine spacer between the DHBA and L-threonine components and is opposite that of Fe(III)-enterobactin, which contains DHBA ligated directly to L-serine.