The pyoverdin receptor FpvA, a TonB-dependent receptor involved in iron uptake by Pseudomonas aeruginosa (review)

Iron is an important element, essential for the growth of almost all living cells. Because of the high insolubility of iron(III) in aerobic conditions, many gram-negative bacteria produce, under iron limitation, small iron-chelating compounds called siderophores, together with new outer-membrane proteins, which function as receptors for the ferrisiderophores. Pseudomonas aeruginosa, an important human opportunistic pathogen, produces at least three known siderophores when grown in iron-deficient conditions: pyochelin, salicylate and pyoverdin. This review focuses on pyoverdin and on the ability of FpvA to bind iron-free and ferric-PaA pyoverdin, in the light of recent information gained from biochemical and biophysical studies and of the recently solved 3D-structures of the related ferrichrome FhuA and enterobactin FepA receptors in Escherichia coli.