Mutually-induced conformational switching of RNA and coat protein underpins efficient assembly of a viral capsid.

ABSTRACT: Single-stranded RNA viruses package their genomes into capsids enclosing fixed volumes. We assayed the ability of bacteriophage MS2 coat protein to package large, defined fragments of its genomic, single-stranded RNA. We show that the efficiency of packaging into a T=3 capsid in vitro is inversely proportional to RNA length, implying that there is a free-energy barrier to be overcome during assembly. All the RNAs examined have greater solution persistence lengths than the internal diameter of the capsid into which they become packaged, suggesting that protein-mediated RNA compaction must occur during assembly. Binding ethidium bromide to one of these RNA fragments, which would be expected to reduce its flexibility, severely inhibited packaging, consistent with this idea. Cryo-EM structures

SUBMITTER: Rolfsson O 

PROVIDER: S-EPMC4793595 | biostudies-literature | 2010 Aug

REPOSITORIES: biostudies-literature