TonB‐dependent iron acquisition: mechanisms of siderophore‐mediated active transport^†

Cells growing in aerobic environments have developed intricate strategies to overcome the scarcity of iron, an essential nutrient. In gram-negative bacteria, high-affinity iron acquisition requires outer membrane-localized proteins that bind iron chelates at the cell surface and promote their uptake. Transport of bound chelates across the outer membrane depends upon TonB-ExbB-ExbD, a cytoplasmic membrane-localized complex that transduces energy...