Characterization of the meningococcal DNA glycosylase Fpg involved in base excision repair.
BACKGROUND
Neisseria meningitidis, the causative agent of meningococcal disease, is exposed to high levels of reactive oxygen species inside its exclusive human host. The DNA glycosylase Fpg of the base excision repair pathway (BER) is a central player in the correction of oxidative DNA damage. This study aimed at characterizing the meningococcal Fpg and its role in DNA repair.


RESULTS
The deduced N. meningitidis Fpg amino acid sequence was highly homologous to other Fpg orthologues, with particularly high conservation of functional domains. As for most N. meningitidis DNA repair genes, the fpg gene contained a DNA uptake sequence mediating efficient transformation of DNA. The recombinant N. meningitidis Fpg protein was over-expressed, purified to homogeneity and assessed for enzymatic activity. N. meningitidis Fpg was found to remove 2,6-diamino-4-hydroxy-5-formamidopyrimidine (faPy) lesions and 7,8-dihydro-8-oxo-2'-deoxyguanosine (8oxoG) opposite of C, T and G and to a lesser extent opposite of A. Moreover, the N. meningitidis fpg single mutant was only slightly affected in terms of an increase in the frequency of phase variation as compared to a mismatch repair mutant.


CONCLUSIONS
Collectively, these findings show that meningococcal Fpg functions are similar to those of prototype Fpg orthologues in other bacterial species.
Tibballs
Katrina L
KL
Centre for Molecular Biology and Neuroscience and Institute of Microbiology, University of Oslo, Rikshospitalet, NO-0027 Oslo, Norway. k.l.tiballs@medisin.uio.no
Ambur
Ole Herman
OH
Alfsnes
Kristian
K
Homberset
Håvard
H
Frye
Stephan A
SA
Davidsen
Tonje
T
Tønjum
Tone
T
D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D004260:DNA Repair; D043382:DNA-Formamidopyrimidine Glycosylase / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D009345:Neisseria meningitidis / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics; D017434:Protein Structure, Tertiary
D001426:Bacterial Proteins; D043382:DNA-Formamidopyrimidine Glycosylase