title: Characterization of the Neisseria meningitidis Helicase RecG.
abstract: Neisseria meningitidis (Nm) is a Gram-negative oral commensal that opportunistically can cause septicaemia and/or meningitis. Here, we overexpressed, purified and characterized the Nm DNA repair/recombination helicase RecG (RecGNm) and examined its role during genotoxic stress. RecGNm possessed ATP-dependent DNA binding and unwinding activities in vitro on a variety of DNA model substrates including a Holliday junction (HJ). Database searching of the Nm genomes identified 49 single nucleotide polymorphisms (SNPs) in the recGNm including 37 non-synonymous SNPs (nsSNPs), and 7 of the nsSNPs were located in the codons for conserved active site residues of RecGNm. A transient reduction in transformation of DNA was observed in the Nm ΔrecG strain as compared to the wildtype. The gene encoding recGNm also contained an unusually high number of the DNA uptake sequence (DUS) that facilitate transformation in neisserial species. The differentially abundant protein profiles of the Nm wildtype and ΔrecG strains suggest that expression of RecGNm might be linked to expression of other proteins involved in DNA repair, recombination and replication, pilus biogenesis, glycan biosynthesis and ribosomal activity. This might explain the growth defect that was observed in the Nm ΔrecG null mutant.
authors.affiliation: Department of Microbiology, University of Oslo, Oslo, Norway.
authors.forename: Getachew Tesfaye
authors.initials: GT
authors.lastname: Beyene
authors.affiliation: Department of Microbiology, Oslo University Hospital (Rikshospitalet), Oslo, Norway.
authors.forename: Seetha V
authors.initials: SV
authors.lastname: Balasingham
authors.affiliation: Department of Microbiology, Oslo University Hospital (Rikshospitalet), Oslo, Norway.
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Frye
authors.affiliation: Department of Microbiology, Oslo University Hospital (Rikshospitalet), Oslo, Norway.
authors.forename: Amine
authors.initials: A
authors.lastname: Namouchi
authors.affiliation: Department of Microbiology, University of Oslo, Oslo, Norway.
authors.forename: Håvard
authors.initials: H
authors.lastname: Homberset
authors.affiliation: Department of Microbiology, University of Oslo, Oslo, Norway.
authors.forename: Shewit
authors.initials: S
authors.lastname: Kalayou
authors.affiliation: Department of Microbiology, University of Oslo, Oslo, Norway.
authors.forename: Tahira
authors.initials: T
authors.lastname: Riaz
authors.affiliation: Department of Microbiology, University of Oslo, Oslo, Norway.|Department of Microbiology, Oslo University Hospital (Rikshospitalet), Oslo, Norway.
authors.forename: Tone
authors.identifier: http://orcid.org/0000-0002-1709-6921
authors.initials: T
authors.lastname: Tønjum
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D001483:Base Sequence; D020134:Catalytic Domain; D003001:Cloning, Molecular / Q000379:methods*; D017124:Conserved Sequence; D004265:DNA Helicases / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D004260:DNA Repair; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D008958:Models, Molecular; D009345:Neisseria meningitidis / Q000201:enzymology / Q000235:genetics / Q000254:growth & development*; D020641:Polymorphism, Single Nucleotide; D011995:Recombination, Genetic; D014169:Transformation, Bacterial
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004265:DNA Helicases