Science Focus
original post »Bacteria, like all living things, need iron for a variety of biochemical functions. Humans and other higher order organisms have plenty of iron; we limit bacterial access to it as a means of defending against bacterial infection. So when we need to transfer iron throughout our bodies, we keep it tightly sequestered in a protein called transferrin.
In order to infect us, bacterial pathogens must try to wrest that iron away; they have specialized transferrin binding proteins (Tbps) to do just that. Recent work demonstrates that transferrin "is engaged in ancient and ongoing evolutionary conflicts" with one of these Tbps, TbpA.
By comparing the genetic sequence of transferrin across twenty-one different primate species, researchers found that transferrin has undergone positive evolutionary selection in a manner often seen in molecular arms races between mammals and viruses. Fourteen of the sixteen rapidly evolving sites identified in transferrin are in amino acids that form direct contact with TbpA from bacterial all-stars like Neisseria meningitidis, which causes meningitis; Neisseria gonorrhoeae, which causes gonorrhea; and Haemophilus influenzae, which can cause pneumonia.
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» see original post http://feeds.arstechnica.com/~r/arstechnica/science/~3/l5mWe1uQ47M/
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