A study indicated the toxin can block the use of amino acids required by the bacteria to produce proteins needed for survival.
Researchers are aiming to use this toxin to develop new anti-TB drugs.
TB causes nearly 1.5 million deaths across the world each year.
While most cases can be cured with proper treatment, the number of antibiotic-resistant infections is steadily increasing.
TB is spread by breathing in tiny droplets from the coughs or sneezes of an infected person, and mainly affects the lungs, although it can affect any part of the body, including bones and nervous system.
This work opens up new avenues of research and discovery for the next generation of drugs
Bacteria, such as the germs that cause TB, produce toxins to help them adapt to stress in the environment.
The toxins are normally counteracted by a matching antidote, but when they are active they can potentially slow bacterial growth and even lead to cell death.
The research, published in Science Advances, found a new toxin called MenT produced by the TB bacterium Mycobacterium tuberculosis.
The researchers built a 3D picture of MenT which, combined with genetic and biochemical data, showed that the toxin inhibits the use of amino acids needed by the bacteria to produce protein.
If not neutralised by its anti-toxin, MenT stalls the growth of Mycobacterium tuberculosis, causing the bacteria to die.
Co-senior author Dr Tim Blower, associate professor in the department of biosciences and Lister Institute Prize Fellow at Durham University, said: “Effectively the tuberculosis is actively poisoning itself.
“Through the forced activation of MenT, or by destabilising the relationship between the toxin and its anti-toxin MenA, we could kill the bacteria that cause TB.
“The remarkable antibacterial properties of such toxins make them of huge therapeutic interest.”
Co-senior author Dr Pierre Genevaux, from the Laboratory of Molecular Microbiology and Genetics/Centre Integrative Biology, said: “Our research identifies a previously unknown mechanism that could block protein synthesis and potentially treat tuberculosis and other infections.
“This work opens up new avenues of research and discovery for the next generation of drugs.”
The study was led by Durham University and the Laboratory of Molecular Microbiology and Genetics/Centre Integrative Biology in France.
