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RNA dependent RNA polymerase from dsRNA bacteriophage phi6 plus templateRNA dependent RNA polymerase from dsRNA bacteriophage phi6 plus template
Structural highlights
FunctionPublication Abstract from PubMedIn 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. A mechanism for initiating RNA-dependent RNA polymerization.,Butcher SJ, Grimes JM, Makeyev EV, Bamford DH, Stuart DI Nature. 2001 Mar 8;410(6825):235-40. PMID:11242087[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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