5IT7

Structure of the Kluyveromyces lactis 80S ribosome in complex with the cricket paralysis virus IRES and eEF2

This is a non-PDB format compatible entry.

Summary for 5IT7

• Entry DOI: 10.2210/pdb5it7/pdb
• EMDB information: 8123
• Descriptor: 25S ribosomal RNA, KLLA0E00573p, KLLA0F04499p, ... (87 entities in total)
• Functional Keywords: ribosome, translocation, ires, eef2
• Biological source: Cricket paralysis virus; More
• Total number of polymer chains: 83
• Total formula weight: 3190108.40

Authors

Murray, J.,Savva, C.G.,Shin, B.S.,Dever, T.E.,Ramakrishnan, V.,Fernandez, I.S. (deposition date: 2016-03-16, release date: 2016-05-18, Last modification date: 2018-11-21)

Primary citation

Murray, J.,Savva, C.G.,Shin, B.S.,Dever, T.E.,Ramakrishnan, V.,Fernandez, I.S.
Structural characterization of ribosome recruitment and translocation by type IV IRES.
Elife, 5:-, 2016

PubMed Abstract: Viral mRNA sequences with a type IV IRES are able to initiate translation without any host initiation factors. Initial recruitment of the small ribosomal subunit as well as two translocation steps before the first peptidyl transfer are essential for the initiation of translation by these mRNAs. Using electron cryomicroscopy (cryo-EM) we have structurally characterized at high resolution how the Cricket Paralysis Virus Internal Ribosomal Entry Site (CrPV-IRES) binds the small ribosomal subunit (40S) and the translocation intermediate stabilized by elongation factor 2 (eEF2). The CrPV-IRES restricts tvhe otherwise flexible 40S head to a conformation compatible with binding the large ribosomal subunit (60S). Once the 60S is recruited, the binary CrPV-IRES/80S complex oscillates between canonical and rotated states (Fernández et al., 2014; Koh et al., 2014), as seen for pre-translocation complexes with tRNAs. Elongation factor eEF2 with a GTP analog stabilizes the ribosome-IRES complex in a rotated state with an extra ~3 degrees of rotation. Key residues in domain IV of eEF2 interact with pseudoknot I (PKI) of the CrPV-IRES stabilizing it in a conformation reminiscent of a hybrid tRNA state. The structure explains how diphthamide, a eukaryotic and archaeal specific post-translational modification of a histidine residue of eEF2, is involved in translocation.

PubMed: 27159451
DOI: 10.7554/eLife.13567

Experimental method

ELECTRON MICROSCOPY (3.6 Å)