Model of a DNA-protein complex of the architectural monomeric protein MC1 from Euryarchaea

PLoS One. 2014 Feb 18;9(2):e88809. doi: 10.1371/journal.pone.0088809. eCollection 2014.

Abstract

In Archaea the two major modes of DNA packaging are wrapping by histone proteins or bending by architectural non-histone proteins. To supplement our knowledge about the binding mode of the different DNA-bending proteins observed across the three domains of life, we present here the first model of a complex in which the monomeric Methanogen Chromosomal protein 1 (MC1) from Euryarchaea binds to the concave side of a strongly bent DNA. In laboratory growth conditions MC1 is the most abundant architectural protein present in Methanosarcina thermophila CHTI55. Like most proteins that strongly bend DNA, MC1 is known to bind in the minor groove. Interaction areas for MC1 and DNA were mapped by Nuclear Magnetic Resonance (NMR) data. The polarity of protein binding was determined using paramagnetic probes attached to the DNA. The first structural model of the DNA-MC1 complex we propose here was obtained by two complementary docking approaches and is in good agreement with the experimental data previously provided by electron microscopy and biochemistry. Residues essential to DNA-binding and -bending were highlighted and confirmed by site-directed mutagenesis. It was found that the Arg25 side-chain was essential to neutralize the negative charge of two phosphates that come very close in response to a dramatic curvature of the DNA.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Archaeal Proteins / chemistry*
  • Archaeal Proteins / metabolism*
  • Base Sequence
  • DNA / chemistry
  • DNA / genetics
  • DNA / metabolism*
  • Models, Molecular*
  • Molecular Docking Simulation
  • Nucleic Acid Conformation
  • Protein Binding
  • Protein Conformation
  • Ribonucleoproteins / chemistry*
  • Ribonucleoproteins / metabolism*
  • Static Electricity
  • Surface Properties

Substances

  • Archaeal Proteins
  • HMb protein, Methanosarcina
  • Ribonucleoproteins
  • DNA

Grants and funding

Funds result from the CNRS. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.