5tbz
From Proteopedia
E. Coli RNA Polymerase complexed with NusG
Structural highlights
Function[NUSG_ECO57] 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 transcriptional antitermination.[HAMAP-Rule:MF_00948] [RPOA_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOC_ECO57] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. [RPOB_ECO45] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. Publication Abstract from PubMedNusG is an essential transcription factor that plays multiple key regulatory roles in transcription elongation, termination and coupling translation and transcription. The core role of NusG is to enhance transcription elongation and RNA polymerase processivity. Here, we present the structure of Escherichia coli RNA polymerase complexed with NusG. The structure shows that the NusG N-terminal domain (NGN) binds at the central cleft of RNA polymerase surrounded by the beta' clamp helices, the beta protrusion, and the beta lobe domains to close the promoter DNA binding channel and constrain the beta' clamp domain, but with an orientation that is different from the one observed in the archaeal beta' clamp-Spt4/5 complex. The structure also allows us to construct a reliable model of the complete NusG-associated transcription elongation complex, suggesting that the NGN domain binds at the upstream fork junction of the transcription elongation complex, similar to sigma2 in the transcription initiation complex, to stabilize the junction, and therefore enhances transcription processivity. Structural insights into NusG regulating transcription elongation.,Liu B, Steitz TA Nucleic Acids Res. 2016 Nov 29. pii: gkw1159. PMID:27899640[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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