Ornibactin

Ornibactin is a siderophore, or small iron-binding compound secreted by bacteria to transport iron into the cell. Ornibactin is produced by Burkholderia cenocepacia under iron-deficient conditions. B. cenocepacia is known to opportunistically infect humans, specifically ones suffering from cystic fibrosis.

Biosynthesis

Ornibactin consists of an L-ornithine-D-hydroxyaspartate-L-serine-L-ornithine backbone. It is biosynthesized by 2 non-ribosomal peptide synthetases, OrbI and OrbJ, as indicated in the figure below. The domains are as follows: adenylation, peptidyl carrier, condensation, and epimerase. The wavy lines in the figure indicate the phosphopantetheine arms to which the amino acid residues are attached via thioester linkages.