A new study published in the journal Nature Chemical Biology brings new insights on the tubercle bacillus (Mycobacterium tuberculosis), which may lead to the development of new treatments against tuberculosis. This research was made by a French – British Team including scientists from CNRS, Inserm , the Institut Curie and UniversitÃ© Toulouse III – Paul Sabatier.
Tuberculosis is an infectious disease affecting the lungs and it can become life threatening if not treated properly. Statistics show that this disease kills 1.5 million people each year. Although there is a vaccine against tuberculosis (BCG), this vaccine has a variable efficacy and the immunity provided is limited. It must also be mentioned that there are antibiotics against tuberculosis but lately there are increasingly more cases of tuberculosis resistant to treatment. This is why doctors want to investigate new strategies for treatment and prevention.
Now researchers have found that aspartate, an amino acid, acts as the main source of nitrogen and it is essential to this bacillus. Moreover, researchers found the mechanism by which M. tuberculosis extracts this amino acid from its host. They now hope that these findings will help them in future studies in order to develop new vaccines and new antibiotics to treat or prevent this infectious disease.
The study led by researchers at the Institute of Structural Biology et Pharmacologie (CNRS / UniversitÃ© Toulouse III – Paul Sabatier ) was aimed to investigate the exact mechanism by which M. tuberculosis supplies itself with nitrogen. Researchers studied a protein called AnsP1 which works as transmembrane proteins for amino acids. It seems that this protein, when introduced into bacteria, is responsible for capturing aspartate.
In addition, researchers showed that the mutant form of a genetically inactivated bacillus cannot survive in an environment that contains aspartate as the only source of nitrogen. The next step was to see if indeed aspartate is the major source of nitrogen for M.tuberculosis. To check this, researchers used a technique that involved the use of heavy isotope of nitrogen and found that indeed the bacillus takes nitrogen from aspartate. These findings prove the hypothesis, namely that AnsP1 is responsible for capturing nitrogen from its host.
Moreover, the experiments on mice showed that the bacillus strains were attenuated when AnsP1 was inactivated. Now researchers hope that AnsP1 will become the new therapeutic target for the discovery of new antibiotics and new more effective vaccines for tuberculosis.