The role of the synergistic phosphate anion in iron transport by the periplasmic iron-binding protein from Haemophilus influenzae.

ABSTRACT: The acquisition of iron from transferrin by Gram-negative bacterial pathogens is dependent on a periplasmic ferric-ion-binding protein, FbpA. FbpA shuttles iron from the outer membrane to an inner membrane transport complex. A bound phosphate anion completes the iron co-ordination shell of FbpA and kinetic studies demonstrate that the anion plays a critical role in iron binding and release in vitro. The present study was initiated to directly address the hypothesis that the synergistic anion is required for transport of iron in intact cells. A series of site-directed mutants in the anion-binding amino acids of the Haemophilus influenzae FbpA (Gln-58, Asn-175 and Asn-193) were prepared to provide proteins defective in binding of the phosphate anion. Crystal structures of various mutants hav

SUBMITTER: Khan AG 

PROVIDER: S-EPMC1828884 | biostudies-literature | 2007 Apr

REPOSITORIES: biostudies-literature