Salmonella typhimurium IroN and FepA proteins mediate uptake of enterobactin but differ in their specificity for other siderophores

Salmonella typhimurium possesses two outer membrane receptor proteins, IroN and FepA, which have been implicated in the uptake of enterobactin. To det ermine whether both receptors have identical substrate specificities, fepA and iroN mutants and a double mutant were characterized. While both recepto rs transported enterobactin, the uptake of corynebactin and myxochelin C wa s selectively mediated by IroN and FepA, respectively.