Characterization of the Neisseria meningitidis Helicase RecG

PLoS One. 2016 Oct 13;11(10):e0164588. doi: 10.1371/journal.pone.0164588. eCollection 2016.

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.

MeSH terms

  • Bacterial Proteins / chemistry
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Base Sequence
  • Catalytic Domain
  • Cloning, Molecular / methods*
  • Conserved Sequence
  • DNA Helicases / chemistry
  • DNA Helicases / genetics*
  • DNA Helicases / metabolism*
  • DNA Repair
  • DNA Replication
  • DNA, Bacterial / metabolism*
  • Models, Molecular
  • Neisseria meningitidis / enzymology
  • Neisseria meningitidis / genetics
  • Neisseria meningitidis / growth & development*
  • Polymorphism, Single Nucleotide
  • Recombination, Genetic
  • Transformation, Bacterial

Substances

  • Bacterial Proteins
  • DNA, Bacterial
  • DNA Helicases

Grants and funding

This work was supported by: The Research Council of Norway (RCN) [http://www.forskningsradet.no/no/Forsiden/1173185591033] (#204747), RCN Centre of Excellence funding to Centre for Molecular Biology and Neuroscience (SFF #145977) and RCN GLOBVAC projects #220901 and 204747 [Helse SørØst http://www.helse-sorost.no/] project 2014050; The Norwegian Agency for Development Cooperation (NORAD) research funding [https://www.norad.no/en/front/]; The University of Oslo Quota program / Norwegian State Educational Loan Fund. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.