A Mechanism for Initiating RNA-Dependent RNA PolymerizationButcher, S.J., Grimes, J.M., Makeyev, E.V., Bamford, D.H., Stuart, D.I.
(2001) Nature 410: 235
- PubMed: 11242087
- DOI: 10.1038/35065653
- Primary Citation of Related Structures:
- PubMed Abstract:
- Crystallization and Preliminary X-Ray Crystallographic Studies on the Bacteriophage Phi6 RNA-Dependent RNA Polymerase
Butcher, S.J.,Makeyev, E.V.,Grimes, J.M.,Stuart, D.I.,Bamford, D.H.
(2000) Acta Crystallogr.,Sect.D 56: 1473
In most RNA viruses, genome replication and transcription are catalysed by a viral RNA-dependent RNA polymerase. Double-stranded RNA viruses perform these operations in a capsid (the polymerase complex), using an enzyme that can read both single- and ...
In most RNA viruses, genome replication and transcription are catalysed by a viral RNA-dependent RNA polymerase. Double-stranded RNA viruses perform these operations in a capsid (the polymerase complex), using an enzyme that can read both single- and double-stranded RNA. Structures have been solved for such viral capsids, but they do not resolve the polymerase subunits in any detail. Here we show that the 2 A resolution X-ray structure of the active polymerase subunit from the double-stranded RNA bacteriophage straight phi6 is highly similar to that of the polymerase of hepatitis C virus, providing an evolutionary link between double-stranded RNA viruses and flaviviruses. By crystal soaking and co-crystallization, we determined a number of other structures, including complexes with oligonucleotide and/or nucleoside triphosphates (NTPs), that suggest a mechanism by which the incoming double-stranded RNA is opened up to feed the template through to the active site, while the substrates enter by another route. The template strand initially overshoots, locking into a specificity pocket, and then, in the presence of cognate NTPs, reverses to form the initiation complex; this process engages two NTPs, one of which acts with the carboxy-terminal domain of the protein to prime the reaction. Our results provide a working model for the initiation of replication and transcription.
Institute of Biotechnology and Department of Biosciences, Viikki Biocenter, PO Box 56 (Viikinkaari 5), 00014 University of Helsinki, Finland.