6flp
From Proteopedia
CryoEM structure of E.coli RNA polymerase paused elongation complex without RNA hairpin bound to NusA
Structural highlights
Function[RPOZ_ECOLI] Promotes RNA polymerase assembly. Latches the N- and C-terminal regions of the beta' subunit thereby facilitating its interaction with the beta and alpha subunits.[HAMAP-Rule:MF_00366] [RPOA_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates. This subunit plays an important role in subunit assembly since its dimerization is the first step in the sequential assembly of subunits to form the holoenzyme.[HAMAP-Rule:MF_00059] [RPOC_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01322] [RPOB_ECOLI] DNA-dependent RNA polymerase catalyzes the transcription of DNA into RNA using the four ribonucleoside triphosphates as substrates.[HAMAP-Rule:MF_01321] Publication Abstract from PubMedTranscriptional pausing by RNA polymerases (RNAPs) is a key mechanism to regulate gene expression in all kingdoms of life and is a prerequisite for transcription termination. The essential bacterial transcription factor NusA stimulates both pausing and termination of transcription, thus playing a central role. Here, we report single-particle electron cryo-microscopy reconstructions of NusA bound to paused E. coli RNAP elongation complexes with and without a pause-enhancing hairpin in the RNA exit channel. The structures reveal four interactions between NusA and RNAP that suggest how NusA stimulates RNA folding, pausing, and termination. An asymmetric translocation intermediate of RNA and DNA converts the active site of the enzyme into an inactive state, providing a structural explanation for the inhibition of catalysis. Comparing RNAP at different stages of pausing provides insights on the dynamic nature of the process and the role of NusA as a regulatory factor. Structural Basis for NusA Stabilized Transcriptional Pausing.,Guo X, Myasnikov AG, Chen J, Crucifix C, Papai G, Takacs M, Schultz P, Weixlbaumer A Mol Cell. 2018 Mar 1;69(5):816-827.e4. doi: 10.1016/j.molcel.2018.02.008. PMID:29499136[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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