The monomeric form of Neisseria DNA mimic protein DMP19 prevents DNA from binding to the histone-like HU protein

PLoS One. 2017 Dec 8;12(12):e0189461. doi: 10.1371/journal.pone.0189461. eCollection 2017.

Abstract

DNA mimicry is a direct and effective strategy by which the mimic competes with DNA for the DNA binding sites on other proteins. Until now, only about a dozen proteins have been shown to function via this strategy, including the DNA mimic protein DMP19 from Neisseria meningitides. We have shown previously that DMP19 dimer prevents the operator DNA from binding to the transcription factor NHTF. Here, we provide new evidence that DMP19 monomer can also interact with the Neisseria nucleoid-associated protein HU. Using BS3 crosslinking, gel filtration and isothermal titration calorimetry assays, we found that DMP19 uses its monomeric form to interact with the Neisseria HU dimer. Crosslinking conjugated mass spectrometry was used to investigate the binding mode of DMP19 monomer and HU dimer. Finally, an electrophoretic mobility shift assay (EMSA) confirmed that the DNA binding affinity of HU is affected by DMP19. These results showed that DMP19 is bifunctional in the gene regulation of Neisseria through its variable oligomeric forms.

MeSH terms

  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Dimerization
  • Histones / metabolism*
  • Molecular Mimicry*
  • Neisseria / metabolism*
  • Protein Binding

Substances

  • Bacterial Proteins
  • Histones

Grants and funding

This work was supported financially by Ministry of Science and Technology (Grant MOST 103-2311-B-038 -005 and MOST 106-2311-B-038 -002). The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.