6z9r
From Proteopedia
Transcription termination intermediate complex 3
Structural highlights
FunctionNUSG_ECOLI Participates in transcription elongation, termination and antitermination. In the absence of Rho, increases the rate of transcription elongation by the RNA polymerase (RNAP), probably by partially suppressing pausing. In the presence of Rho, modulates most Rho-dependent termination events by interacting with the RNAP to render the complex more susceptible to the termination activity of Rho. May be required to overcome a kinetic limitation of Rho to function at certain terminators. Also involved in ribosomal RNA and phage lambda N-mediated transcriptional antitermination.[1] [2] [3] [4] [5] [6] [7] [8] [9] Publication Abstract from PubMedFactor-dependent transcription termination mechanisms are poorly understood. We determined a series of cryo-electron microscopy structures portraying the hexameric adenosine triphosphatase (ATPase) rho on a pathway to terminating NusA/NusG-modified elongation complexes. An open rho ring contacts NusA, NusG, and multiple regions of RNA polymerase, trapping and locally unwinding proximal upstream DNA. NusA wedges into the rho ring, initially sequestering RNA. Upon deflection of distal upstream DNA over the RNA polymerase zinc-binding domain, NusA rotates underneath one capping rho 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 rho, and other termination factors across life, may use analogous strategies to allosterically trap transcription complexes in a moribund state. Steps toward translocation-independent RNA polymerase inactivation by terminator ATPase rho.,Said N, Hilal T, Sunday ND, Khatri A, Burger J, Mielke T, Belogurov GA, Loll B, Sen R, Artsimovitch I, Wahl MC Science. 2021 Jan 1;371(6524):eabd1673. doi: 10.1126/science.abd1673. Epub 2020 , Nov 26. PMID:33243850[10] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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