It looks like a fluorescent pill, but this image of an E. coli cell actually shows a new potential target in the fight against infectious diseases. The green highlights a protein called TonB, which is produced by many gram-negative bacteria, including those that cause typhoid fever, meningitis and dysentery. TonB lets bacteria take up iron from the host’s body, which they need to survive. New research from Phillip Klebba of Kansas State University and his colleagues shows how TonB powers iron uptake. When TonB spins within the cell envelope (the bacteria’s “skin”) like a tiny motor, it produces energy that lets another protein pull iron into the cell. This knowledge may lead to the development of antibiotics that block the motion of TonB, potentially stopping an infection in its tracks.