Iron(3+)-hydroxamate-binding protein FhuD (FhuD)

FhuD is a soluble periplasmic binding protein found in gram-negative (e.g., Escherichia coli) and some gram-positive bacteria, functioning as part of a high-affinity ABC transporter system for iron acquisition. It binds ferrichrome and other hydroxamate-type siderophores, capturing the Fe3+-siderophore complex in the periplasm and delivering it to the FhuCDB (in E. coli) or similar membrane transport systems for active translocation across the cytoplasmic membrane. The process is essential for bacterial survival in iron-limited environments, such as within animal hosts, and contributes to bacterial virulence. FhuD exhibits a class III solute-binding protein fold; its ligand binding and conformational changes facilitate unidirectional iron transport and integration with membrane-bound transporter components. Targeting FhuD and related siderophore receptors is a proposed strategy for antimicrobial development, including "Trojan horse" antibiotics using siderophore mimics for selective drug uptake in bacteria.

Other names

Ferrichrome transporter FhuDIron(3+)-hydroxamate-binding protein FhuDPeriplasmic binding protein FhuDfhuD protein, E. coli

Drugs mimicking siderophore structure are internalized via FhuD-dependent transport (e.g., albomycin) Inhibition or blockage of iron acquisition via FhuD can disrupt bacterial growth and pathogenicity