Figure 5.
E. coli siderophore export and import mechanism. The siderophore is the green-blue arrowhead and the red spheres are iron. Proteins involved in siderophore export are colored in yellow, while proteins involved in import of ferric-siderophores are colored in green. In the cytoplasm, the ferric-siderophore esterase induces the release of iron from E. coli enterobactin by modification of the siderophore, whereas the ferric-siderophore reductase reduces the iron in non-E. coli siderophores to induce its release. In E. coli, siderophores are recycled.