Iron Transport and Receptors in Bacteria
Iron is an essential micronutrient for bacteria, acting as a critical cofactor for enzymes in processes like cellular respiration and DNA synthesis, but its availability is often severely limited, especially within a host. To overcome this scarcity, bacteria have evolved sophisticated acquisition systems, which frequently involve secreting high-affinity iron-chelating molecules called siderophores. These siderophores scavenge iron from the environment, and the resulting iron-siderophore complexes are then recognized and bound by specific receptor proteins located on the bacterial cell surface. This binding event initiates an active transport process that shuttles the iron across the cell envelope into the cytoplasm, a mechanism that is not only vital for bacterial survival but also a key virulence factor for many pathogenic species.