Ferrichrome transport system (FhuA)

FhuA is an outer membrane protein in Gram-negative bacteria, primarily functioning as a receptor for ferrichrome, a siderophore that facilitates iron uptake. It's a 22-stranded β-barrel with an internal "cork" domain that blocks passive diffusion until substrate binding. FhuA also serves as a receptor for bacteriophages, colicins, and some antibiotics. Its activity is energy-dependent, requiring interaction with the TonB protein complex.

Other names

Ferrichrome receptorFerric hydroxamate uptake ATonA

Active transport of ferrichrome-bound iron across the outer membrane, requiring interaction with the TonB protein complex and energy from proton motive force. Also exploited by bacteriophages and microcins for cell entry.