D. Research Applications:

2. Mediated Transport and Uptake of Iron by E. Coli
Research by K. Raymond (University of California Berkeley) and W. Rastetter (MIT)
b. Contrasting the Biological Activity of [Δ-Iron(III)enterobactin]3- and [Λ-Iron(III)enantio-enterobactin]3-


This is the Proposed Structure of [Δ-Iron(III)enterobactin]3-
based on the crystal structure of [Δ-Vanadium(IV)enterobactin]2-
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Enterobactin is biosynthesized by E. Coli. Enterobactin binds to iron to form only the [Δ-Iron(III)enterobactin]3- complex which does support bacterial growth by providing the essential element iron to E. Coli
This is the Proposed Structure for [Λ-Iron(III)enantio-enterobactin]3-.
Entantioenterobactin was synthesized by W. Rastetter and his research collegues at MIT from D-Serine. It is abbreviated enEnt or D-ent
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Enantio-Enterobactin forms only the [Λ-Iron(III)enantio-enterobactin]3- isomer and this isomer does not support growth in E. coli.

Reference: Rastetter, W.H., Erickson, T.J., Venuti, M. C.; The Journal of Organic Chemistry, Vol 46, 1981, p. 3579-3590. DOI

Raymond's group established that recognition of the complexes by the FepA protein receptor was NOT stereoselective even though recognition occurred on the metal tris chelate region of the molecule. Iron release from [Δ-Iron(III)enterobactin]3- in the cytoplasm was stereoselective: The esterase responsible for cleaving the ester backbone (Fes) that facilitates iron reduction and release is stereoselective in E. coli for the tri-L-serine backbone

References: Abergei, R.J., Warner, J.A., Shuh, D.K., Raymond, K.N.; J. Am. Chem. Soc. Vol 128, 2006 8920-8931
Thulasiraman, P., Newton, S.M.C., Xu, J., Raymond, K.N., Mai, C., Hall, A., Montague, M.A., Klebba, P.E.; J. Bacteriol. Vol 180(24), 19986689-6696
Abergei, R.J., Zawakska, A.M., Hoette, T.M., Raymond, K.N.; J. Am. Chem. Soc. Vol 131, 2009 12682-12692
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Resources developed by Marion E. Cass, Carleton College and updated in 2014. Computations and content done in consultation with Henry S. Rzepa, Imperial College, London