What are siderophores? If you’ve never heard of them, you’re not alone. Siderophores were discovered many decades ago and there are hundreds of different types of siderophores because different bacteria produce different siderophores. Siderophores are small molecules that are produced by bacteria to scavenge for Iron (III) that’s outside the cell. While many biological roles of siderophores have been discovered, the full extent of their roles are still being studied. Right now, there is a lot of focus in studying siderophores as agents to introduce antibiotics into the cell as well as their roles in iron isolation from cancerous cells.

Just like us, bacteria need iron as a micronutrient. Essentially, bacteria need iron to grow because many proteins and metabolic pathways require iron. However, most iron is found in the insoluble iron (III) form. Siderophores that are secreted from the cell fight with their host cells for free iron (III) in a game of bacterial warfare. Once iron (III) is bound to the siderophore, the siderophore can reenter the cell through specific receptor proteins. Because of the different pH within the cell the iron (III) is converted to the usable iron (II). Usually after the siderophore has done it’s job, it is broken down within the cell.