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

• Published in: Science (American Association for the Advancement of Science) Vol. 371; no. 6524
• Main Authors: Said, Nelly, Hilal, Tarek, Sunday, Nicholas D, Khatri, Ajay, Bürger, Jörg, Mielke, Thorsten, Belogurov, Georgiy A, Loll, Bernhard, Sen, Ranjan, Artsimovitch, Irina, Wahl, Markus C
• Format: Journal Article
• Language: English
• Published: United States The American Association for the Advancement of Science 01.01.2021
• Subjects: Adenosine triphosphatase; Adenosine Triphosphatases - chemistry; Adenosine triphosphate; Cryoelectron Microscopy; Deactivation; Deoxyribonucleic acid; DNA; DNA-directed RNA polymerase; DNA-Directed RNA Polymerases - chemistry; Escherichia coli; Escherichia coli - genetics; Escherichia coli Proteins - chemistry; Inactivation; Microscopy; Multiprotein Complexes - chemistry; Peptide Elongation Factors - chemistry; Protein Conformation; Protein Transport; Rho Factor - chemistry; RNA polymerase; Structural Analysis (Linguistics); Structural Analysis (Science); Transcription Elongation, Genetic; Transcription Factors - chemistry; Transcriptional Elongation Factors - chemistry; Translocation; Zinc Fingers
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.abd1673

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.