Two endonuclease enzymes, which cut DNA at specific points, appear to protect the genetic material of Neisseria meningitidis from oxidative damage caused by human white blood cells. This UK study focused on AP endonuclease (NApe) and 3-phosphodiesterase (NExo), which were identified from the meningitis genome.
Assays were used to assess the role of each enzyme in bacterial survival under oxidative stress.
For the study, N. meningitidis strains were constructed lacking NApe, NExo or both enzymes.
On exposure to oxidative stress, strains of meningitis lacking either of the two enzymes lost 40 per cent of their bacterial population than the normal strain.
Among mutants missing both strains, 70 per cent more bacteria died than in the normal strain.
This suggests that both enzymes are necessary for the survival of N. meningitidis under oxidative stress and during bloodstream infection.
Identifying a way to disable these enzymes would render the N. meningitidis unable to repair itself.
This would therefore leave it vulnerable to attack and defeat by the body’s immune system, suggest the researchers.