New finding points way to foiling anthrax's tricks

Anthrax bacteria (green) secrete two iron-scavenging molecules, the siderophores bacillibactin and petrobactin, represented by ball-and-stick structures with a red iron atom inside. One of these, bacillibactin (top right), is intercepted by the protein siderocalin (blue) produced by the human immune system, but the second, petrobactin (lower left), slips through the body's defenses. (Raymond lab/UC Berkeley)