Structural Basis for NusA Stabilized Transcriptional Pausing.
Fiche publication
Date publication
mars 2018
Journal
Molecular cell
Auteurs
Membres identifiés du Cancéropôle Est :
Dr SCHULTZ Patrick
Tous les auteurs :
Guo X, Myasnikov AG, Chen J, Crucifix C, Papai G, Takacs M, Schultz P, Weixlbaumer A
Lien Pubmed
Résumé
Transcriptional 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.
Mots clés
NusA, RNA polymerase structure, cryo-EM, his-pause, transcription, transcriptional pausing
Référence
Mol. Cell. 2018 Mar 1;69(5):816-827.e4