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Structural Basis and Stereochemistry of Triscatecholate Siderophore Binding by FeuA


  • This work was supported by the DFG (MA811/23-1). We thank Christoph Müller-Dieckmann, Alexander Popov, and Xavier Thibault at ESRF for help with data recording. We also thank Thomas Knappe and Maryna Batokha (research student) for help with spectroscopic measurements and Detlef Eppers and Markus Oberthür for providing mecam.


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An iron will: The cyclic depsipeptide ferribacillibactin ([FeIIIBB]3−) is tightly bound by the siderophore binding protein FeuA (see picture). The FeuA/[FeIIIBB]3− complex contains a basic triad, which interacts with the triscatecholate unit of the siderophore. H2O molecules stabilize [FeIIIBB]3− in an energetically unfavored conformation. FeuA allows only a Λ configuration at the ferri-triscatecholate metal center and can thus alter the configuration of a Δ species upon binding.