SNAP output for PDB entry 8him [SNAP web server]

PDB-id

8him; SNAP-derived features in text and JSON formats; DNAproDB

Class

transcription

Method

cryo-EM (2.8 Å)

Summary

A cryo-EM structure of b. oleracea RNA polymerase v elongation complex at 2.73 angstrom

Reference

Xie G, Du X, Hu H, Li S, Cao X, Jacobsen SE, Du J (2023): "Structure and mechanism of the plant RNA polymerase V." Science, 379, 1209-1213. doi: 10.1126/science.adf8231.

Abstract

In addition to the conserved RNA polymerases (Pols) I-III in eukaryotes, two atypical polymerases, Pols IV and V, specifically produce non-coding RNA in the RNA-directed DNA methylation (RdDM) pathway in plants. Here, we report on the structures of cauliflower Pol V in the free and elongation conformations. A conserved tyrosine residue of NRPE2 stacks with a dsDNA branch of the transcription bubble to potentially attenuate elongation by inducing transcription stalling. The non-template DNA strand is captured by NRPE2 to enhance backtracking, thereby increasing 3'-5' cleavage which likely underpins Pol V's high fidelity. The structures also illuminate the mechanism of Pol V transcription stalling and enhanced backtracking which may be important for Pol V's retention on chromatin to serve its function in tethering downstream factors for RdDM.