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Caption
When bacteria that cause infectious diseases invade, the host starves the bacteria by hiding circulating iron, an essential nutrient it needs for survival, within the folds of a protein called transferrin. When the bacterial protein, TbpA, grasps hold of the primate protein, transferrin, it can steal transferrin's iron. LEFT - Plotted on the primate and bacterial family trees, transferrin has evolved mutations (green circles) over evolutionary time that allow it to evade TbpA. TbpA, in turn, has evolved mutations (blue circles) that again enable it to grasp hold of transferrin and steal it's iron. RIGHT - Depiction of transferrin and TbpA proteins, and the consequences of mutations in each. The evolutionary arms race has lasted 40 million years, highlighting the importance of the primate defense mechanism, called nutritional immunity, in the conflict between host and bacterial pathogen.
Credit
Janet Iwasa, Ph.D., University of Utah
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Credit Janet Iwasa, Ph.D., University of Utah