( his colleagues have discovered that the...)Scientists find missing enzyme for tuberculosis iron scavenging pathway

"What the structure showed, when combined with careful analysis of the sequence, its neighbors in the genome, and the fact that its gene was also regulated by iron, was that Rv1347c was almost certainly a "missing enzyme" from the pathway for biosynthesis of the iron scavenging agent mycobactin," recalls Dr. Baker.

"Mycobactin is a small molecule which binds iron very tightly. Bacteria synthesize it so that they can acquire the iron they need to grow ?it is secreted out into the external environment where it scavenges iron and then (with iron bound to it) it is taken up by the bacterium again."

Although Rv1347c is not involved in antibiotic resistance, it still remains a target for the design of new anti-TB drugs. "Enzymes that synthesize mycobactin are drug targets, because if mycobactin biosynthesis is stopped, the bacterium cannot acquire the iron that it needs for survival," explains Dr. Baker. "Importantly this seems to be true even of the bacteria that are taken up by macrophages in the lung and enter a dormant state ?these are the hardest to attack with drugs."