2agn
From Proteopedia
Fitting of hepatitis C virus internal ribosome entry site domains into the 15 A Cryo-EM map of a HCV IRES-80S ribosome (H. sapiens) complex
Overview
Initiation of translation of the hepatitis C virus (HCV) polyprotein is driven by an internal ribosome entry site (IRES) RNA that bypasses much of the eukaryotic translation initiation machinery. Here, single-particle electron cryomicroscopy has been used to study the mechanism of HCV IRES-mediated initiation. A HeLa in vitro translation system was used to assemble human IRES-80S ribosome complexes under near physiological conditions; these were stalled before elongation. Domain 2 of the HCV IRES is bound to the tRNA exit site, touching the L1 stalk of the 60S subunit, suggesting a mechanism for the removal of the HCV IRES in the progression to elongation. Domain 3 of the HCV IRES positions the initiation codon in the ribosomal mRNA binding cleft by binding helix 28 at the head of the 40S subunit. The comparison with the previously published binary 40S-HCV IRES complex reveals structural rearrangements in the two pseudoknot structures of the HCV IRES in translation initiation.
About this Structure
Full crystallographic information is available from OCA.
Reference
Structure of the hepatitis C Virus IRES bound to the human 80S ribosome: remodeling of the HCV IRES., Boehringer D, Thermann R, Ostareck-Lederer A, Lewis JD, Stark H, Structure. 2005 Nov;13(11):1695-706. PMID:16271893 Page seeded by OCA on Sat May 3 19:01:34 2008
