An autoinhibited state in the structure of Thermotoga maritima NusG

Structure. 2013 Mar 5;21(3):365-75. doi: 10.1016/j.str.2012.12.015. Epub 2013 Feb 14.

Abstract

NusG is a conserved regulatory protein interacting with RNA polymerase (RNAP) and other proteins to form multicomponent complexes that modulate transcription. The crystal structure of Thermotoga maritima NusG (TmNusG) shows a three-domain architecture, comprising well-conserved amino-terminal (NTD) and carboxy-terminal (CTD) domains with an additional, species-specific domain inserted into the NTD. NTD and CTD directly contact each other, occluding a surface of the NTD for binding to RNAP and a surface on the CTD interacting either with transcription termination factor Rho or transcription antitermination factor NusE. NMR spectroscopy confirmed the intramolecular NTD-CTD interaction up to the optimal growth temperature of Thermotoga maritima. The domain interaction involves a dynamic equilibrium between open and closed states and contributes significantly to the overall fold stability of the protein. Wild-type TmNusG and deletion variants could not replace endogenous Escherichia coli NusG, suggesting that the NTD-CTD interaction of TmNusG represents an autoinhibited state.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins / chemistry*
  • Bacterial Proteins / genetics
  • Binding Sites
  • Crystallography, X-Ray
  • DNA-Directed RNA Polymerases / chemistry
  • DNA-Directed RNA Polymerases / genetics
  • Escherichia coli / chemistry
  • Escherichia coli / genetics
  • Escherichia coli / growth & development
  • Escherichia coli Proteins / chemistry*
  • Escherichia coli Proteins / genetics
  • Genetic Complementation Test
  • Molecular Dynamics Simulation
  • Peptide Elongation Factors / chemistry*
  • Peptide Elongation Factors / genetics
  • Protein Binding
  • Protein Interaction Domains and Motifs
  • Protein Stability
  • Protein Structure, Secondary
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / genetics
  • Rho Factor / chemistry
  • Rho Factor / genetics
  • Ribosomal Proteins / chemistry
  • Ribosomal Proteins / genetics
  • Species Specificity
  • Structure-Activity Relationship
  • Thermotoga maritima / chemistry*
  • Thermotoga maritima / genetics
  • Transcription Factors / chemistry*
  • Transcription Factors / genetics

Substances

  • Bacterial Proteins
  • Escherichia coli Proteins
  • NusG protein, E coli
  • Peptide Elongation Factors
  • Recombinant Proteins
  • Rho Factor
  • Ribosomal Proteins
  • Transcription Factors
  • ribosomal protein S10
  • DNA-Directed RNA Polymerases