Download MendeleyStructure of the Rho transcription terminator: mechanism of mRNA recognition and helicase loading
Skordalakes, E., Berger, J.M.(2003) Cell 114: 135-146
- PubMed: 12859904
- DOI: https://doi.org/10.1016/s0092-8674(03)00512-9
- Primary Citation of Related Structures:
1PV4, 1PVO - PubMed 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.
Organizational Affiliation:
Department of Molecular and Cell Biology, University of California, Berkeley, 239 Hildebrand Hall, #3206, Berkeley, CA 94720, USA.
