Bacillus anthracis gets iron from hemoglobin
Iron is an essential nutrient used by almost all organisms. Bacterial pathogens must acquire iron in order to grow inside mammalian hosts. The host, however, limits the availability of free iron – in vertebrate hosts iron is mostly sequestered by heme and bound to hemoglobin within red blood cells. This provides an effective defense strategy against infection. In response, bacteria have evolved clever ways to subvert host sequestration of iron. In Bacillus anthracis, the spore-forming agent of anthrax, the mechanisms of iron scavenging from hemoglobin are unknown. A recent paper reports that B. anthracis produces two proteins which act to acquire iron complexed to heme, a co-factor of host hemoproteins such as hemoglobin. This activity is dependent on a conserved protein domain found in many Gram-positive bacterial pathogens and is necessary for growth of B. anthracis in low-iron environments. These results yield a greater understanding of the mechanisms used by bacterial pathogens to subvert host defenses and provide an avenue for the development of anti-infectives that aim to block these strategies.
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Tags: Bacteria, Biology, Health, Medicine, Microbiology, Science
