SNAP output for PDB entry 6xav [SNAP web server]

PDB-id

6xav; SNAP-derived features in text and JSON formats; DNAproDB

Class

transcription

Method

cryo-EM (7.7 Å)

Summary

Cryoem structure of e. coli rho-dependent transcription pre-termination complex bound with nusg

Reference

Hao Z, Epshtein V, Kim KH, Proshkin S, Svetlov V, Kamarthapu V, Bharati B, Mironov A, Walz T, Nudler E (2021): "Pre-termination Transcription Complex: Structure and Function." Mol.Cell, 81, 281. doi: 10.1016/j.molcel.2020.11.013.

Abstract

Rho is a general transcription termination factor playing essential roles in RNA polymerase (RNAP) recycling, gene regulation, and genomic stability in most bacteria. Traditional models of transcription termination postulate that hexameric Rho loads onto RNA prior to contacting RNAP and then translocates along the transcript in pursuit of the moving RNAP to pull RNA from it. Here, we report the cryoelectron microscopy (cryo-EM) structures of two termination process intermediates. Prior to interacting with RNA, Rho forms a specific "pre-termination complex" (PTC) with RNAP and elongation factors NusA and NusG, which stabilize the PTC. RNA exiting RNAP interacts with NusA before entering the central channel of Rho from the distal C-terminal side of the ring. We map the principal interactions in the PTC and demonstrate their critical role in termination. Our results support a mechanism in which the formation of a persistent PTC is a prerequisite for termination.