Pseudobactin

Pseudobactin is a microbial siderophore produced by a strain of Pseudomonas. The ferrated compound was crystallized (C₄₂H₅₇N₁₂O₁₆Fe·13H₂O) and structure determined by x-ray diffraction. The iron-binding ligands are a hydroxymate moiety from N^d-hydroxyornithine, an a-hydroxy acid from B-hydroxyaspartic acid, an o-dihydroxy aromatic group (catechol) from the quinoline derivative.

Show central Fe and nearest neighbors: 6 O

This model shows the near-perfect octahedral coordination of the central Fe atom, with six oxygens as the apices of the octahedron. The symmetry of the central Fe atom with its nearest neighbors is one of the key factors in chelate stability.

In spacefilling mode, this model show that the central Fe atom is nearly completely concealed by coordinating oxygens. No coordination by additional water (H₂O) or hydroxide (OH^-) is permitted in this structure, which adds to the stability of this chelate.

Show linear hexapeptide backbone

Identify the six amino acids in the hexapeptide!

Show the quinoline derivative

The quinoline moiety gives unferrated pseudobactin a fluorescent yellow-green color. Upon addition of ferric salts and formation of ferric pseudobactin, the color of the compound is reddish brown.

Show all atoms

Reference

M. Teintze, MB Hossain, CL Barnes, J Leong, and D. van der Helm. 1981. Structure of ferric pseudobactin, a siderophore from a plant growth promoting Pseudomonas. Biochem. 20:6446-6457.

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Original release: 23 Feb 1999;