Steps toward translocation-independent RNA polymerase inactivation by terminator ATPase ρ

Science. 2021 Jan 1;371(6524):eabd1673. doi: 10.1126/science.abd1673. Epub 2020 Nov 26.


Factor-dependent transcription termination mechanisms are poorly understood. We determined a series of cryo-electron microscopy structures portraying the hexameric adenosine triphosphatase (ATPase) ρ on a pathway to terminating NusA/NusG-modified elongation complexes. An open ρ ring contacts NusA, NusG, and multiple regions of RNA polymerase, trapping and locally unwinding proximal upstream DNA. NusA wedges into the ρ ring, initially sequestering RNA. Upon deflection of distal upstream DNA over the RNA polymerase zinc-binding domain, NusA rotates underneath one capping ρ subunit, which subsequently captures RNA. After detachment of NusG and clamp opening, RNA polymerase loses its grip on the RNA:DNA hybrid and is inactivated. Our structural and functional analyses suggest that ρ, and other termination factors across life, may use analogous strategies to allosterically trap transcription complexes in a moribund state.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / chemistry*
  • Cryoelectron Microscopy
  • DNA-Directed RNA Polymerases / chemistry*
  • Escherichia coli / genetics*
  • Escherichia coli Proteins / chemistry
  • Multiprotein Complexes / chemistry
  • Peptide Elongation Factors / chemistry
  • Protein Conformation
  • Protein Transport
  • Rho Factor / chemistry*
  • Transcription Elongation, Genetic*
  • Transcription Factors / chemistry
  • Transcriptional Elongation Factors / chemistry
  • Zinc Fingers


  • Escherichia coli Proteins
  • Multiprotein Complexes
  • NusG protein, E coli
  • Peptide Elongation Factors
  • Rho Factor
  • Transcription Factors
  • Transcriptional Elongation Factors
  • nusA protein, E coli
  • DNA-Directed RNA Polymerases
  • Adenosine Triphosphatases