Summary information and primary citation

PDB-id
4h5o; SNAP-derived features in text and JSON formats; DNAproDB
Class
viral protein-RNA
Method
X-ray (3.9 Å)
Summary
Crystal structure of rift valley fever virus nucleocapsid protein pentamer bound to single-stranded RNA
Reference
Raymond DD, Piper ME, Gerrard SR, Skiniotis G, Smith JL (2012): "Phleboviruses encapsidate their genomes by sequestering RNA bases." Proc.Natl.Acad.Sci.USA, 109, 19208-19213. doi: 10.1073/pnas.1213553109.
Abstract
Rift Valley fever and Toscana viruses are human pathogens for which no effective therapeutics exist. These and other phleboviruses have segmented negative-sense RNA genomes that are sequestered by a nucleocapsid protein (N) to form ribonucleoprotein (RNP) complexes of irregular, asymmetric structure, previously uncharacterized at high resolution. N binds nonspecifically to single-stranded RNA with nanomolar affinity. Crystal structures of Rift Valley fever virus N-RNA complexes reconstituted with defined RNAs of different length capture tetrameric, pentameric and hexameric N-RNA multimers. All N-N subunit contacts are mediated by a highly flexible α-helical arm. Arm movement gives rise to the three multimers in the crystal structures and also explains the asymmetric architecture of the RNP. Despite the flexible association of subunits, the crystal structures reveal an invariant, monomeric RNP building block, consisting of the core of one N subunit, the arm of a neighboring N, and four RNA nucleotides with the flanking phosphates. Up to three additional RNA nucleotides bind between subunits. The monomeric building block is matched in size to the repeating unit in viral RNP, as visualized by electron microscopy. N sequesters four RNA bases in a narrow hydrophobic binding slot and has polar contacts only with the sugar-phosphate backbone, which faces the solvent. All RNA bases, whether in the binding slot or in the subunit interface, face the protein in a manner that is incompatible with base pairing or with "reading" by the viral polymerase.

Cartoon-block schematics in six views (download the tarball)

PyMOL session file Download PDB file View in 3Dmol.js