2noq

Publication Abstract from PubMed

Internal ribosome entry sites (IRESs) facilitate an alternative, end-independent pathway of translation initiation. A particular family of dicistroviral IRESs can assemble elongation-competent 80S ribosomal complexes in the absence of canonical initiation factors and initiator transfer RNA. We present here a cryo-EM reconstruction of a dicistroviral IRES bound to the 80S ribosome. The resolution of the cryo-EM reconstruction, in the subnanometer range, allowed the molecular structure of the complete IRES in its active, ribosome-bound state to be solved. The structure, harboring three pseudoknot-containing domains, each with a specific functional role, shows how defined elements of the IRES emerge from a compactly folded core and interact with the key ribosomal components that form the A, P and E sites, where tRNAs normally bind. Our results exemplify the molecular strategy for recruitment of an IRES and reveal the dynamic features necessary for internal initiation.

Structure of the ribosome-bound cricket paralysis virus IRES RNA.,Schuler M, Connell SR, Lescoute A, Giesebrecht J, Dabrowski M, Schroeer B, Mielke T, Penczek PA, Westhof E, Spahn CM Nat Struct Mol Biol. 2006 Dec;13(12):1092-6. Epub 2006 Nov 19. PMID:17115051^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.