1kpz
From Proteopedia
PEMV-1 P1-P2 Frameshifting Pseudoknot Regularized Average Structure
Overview
A hairpin-type messenger RNA pseudoknot from pea enation mosaic virus RNA1 (PEMV-1) regulates the efficiency of programmed -1 ribosomal frameshifting. The solution structure and 15N relaxation rates reveal that the PEMV-1 pseudoknot is a compact-folded structure composed almost entirely of RNA triple helix. A three nucleotide reverse turn in loop 1 positions a protonated cytidine, C(10), in the correct orientation to form an A((n-1)).C(+).G-C(n) major groove base quadruple, like that found in the beet western yellows virus pseudoknot and the hepatitis delta virus ribozyme, despite distinct structural contexts. A novel loop 2-loop 1 A.U Hoogsteen base-pair stacks on the C(10)(+).G(28) base-pair of the A(12).C(10)(+).G(28)-C(13) quadruple and forms a wedge between the pseudoknot stems stabilizing a bent and over-rotated global conformation. Substitution of key nucleotides that stabilize the unique conformation of the PEMV-1 pseudoknot greatly reduces ribosomal frameshifting efficacy.
About this Structure
Full crystallographic information is available from OCA.
Reference
Solution structure of a luteoviral P1-P2 frameshifting mRNA pseudoknot., Nixon PL, Rangan A, Kim YG, Rich A, Hoffman DW, Hennig M, Giedroc DP, J Mol Biol. 2002 Sep 20;322(3):621-33. PMID:12225754 Page seeded by OCA on Fri May 2 23:01:53 2008
