Toxin-antitoxin system and advance in Mycobacterium tuberculosis

Members of toxin-antitoxin system (TAs)are abundant in free-living prokaryotes and virtually absent from obligate host-associated organisms.Gene polymorphism analysis has shown that they have a common ancestor.The protein crystal structure and mode of action of TAs have been analyzed.TAs proteins have the activity of RNA enzymes and could cut mRNA in the particular location of mRNA bases,so they play an important role in dormant injection of bacteria and acclimationas stimulus.Further studies on the Mycobacterium tuberculosis genome-wide have shown that Mycobacterium tuberculosis has as much as 36 pairs of TAs loci,and only small numbers of TAs have been demonstrated. Key words: Toxin-antitoxin system; Crystal structure; RNA enzyme; Mycobacterium tuberculosis