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-ch elating compounds called siderophores, together with new outer-membrane pro teins, which function as receptors for the ferrisiderophores. Pseudomonas a eruginosa, an important human opportunistic pathogen, produces at least thr ee known siderophores when grown in iron-deficient conditions: pyochelin, s alicylate and pyoverdin. This review focuses on pyoverdin and on the abilit y of FpvA to bind iron-free and ferric-PaA pyoverdin, in the light of recen t information gained from biochemical and biophysical studies and of the re cently solved 3D-structures of the related ferrichrome FhuA and enterobacti n FepA receptors in Escherichia coli.