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Although oxidative stress is a key aspect of innate immunity, little is known about how host-restricted pathogens successfully repair DNA damage. Base excision repair is responsible for correcting nucleobases damaged by oxidative stress, and is essential for bloodstream infection caused by the human pathogen, Neisseria meningitidis. We have characterized meningococcal base excision repair enzymes involved in the recognition and removal of damaged nucleobases, and incision of the DNA backbone. We demonstrate that the bi-functional glycosylase/lyases Nth and MutM share several overlapping activities and functional redundancy. However, MutM and other members of the GO system, which deal with 8-oxoG, a common lesion of oxidative damage, are not required for survival of N. meningitidis under oxidative stress. Instead, the mismatch repair pathway provides back-up for the GO system, while the lyase activity of Nth can substitute for the meningococcal AP endonuclease, NApe. Our genetic and biochemical evidence shows that DNA repair is achieved through a robust network of enzymes that provides a flexible system of DNA repair. This network is likely to reflect successful adaptation to the human nasopharynx, and might provide a paradigm for DNA repair in other prokaryotes.

Original publication

DOI

10.1111/j.1365-2958.2012.07989.x

Type

Journal article

Journal

Mol Microbiol

Publication Date

03/2012

Volume

83

Pages

1064 - 1079

Keywords

Bacterial Proteins, DNA Damage, DNA Repair, DNA, Bacterial, DNA-Formamidopyrimidine Glycosylase, Deoxyribonuclease (Pyrimidine Dimer), Neisseria meningitidis, Oxidative Stress