SNAP annotations: PDB entry 1pvo

PDB-id

1pvo; DSSR-derived features in text and JSON formats; DNAproDB

Class

transcription-RNA

Method

X-ray (3.0 Å)

Summary

X-ray crystal structure of rho transcription termination factor in complex with ssrna substrate and anppnp

Reference

Skordalakes E, Berger JM (2003): "Structure of the Rho transcription terminator: mechanism of mRNA recognition and helicase loading." Cell(Cambridge,Mass.), 114, 135-146. doi: 10.1016/S0092-8674(03)00512-9.

Abstract

In bacteria, one of the major transcriptional termination mechanisms requires a RNA/DNA helicase known as the Rho factor. We have determined two structures of Rho complexed with nucleic acid recognition site mimics in both free and nucleotide bound states to 3.0 A resolution. Both structures show that Rho forms a hexameric ring in which two RNA binding sites--a primary one responsible for target mRNA recognition and a secondary one required for mRNA translocation and unwinding--point toward the center of the ring. Rather than forming a closed ring, the Rho hexamer is split open, resembling a "lock washer" in its global architecture. The distance between subunits at the opening is sufficiently wide (12 A) to accommodate single-stranded RNA. This open configuration most likely resembles a state poised to load onto mRNA and suggests how related ring-shaped enzymes may be breached to bind nucleic acids.