2NBX: Solution structure of the J-K region of EMCV IRES

Many viruses bypass canonical cap-dependent translation in host cells by using internal ribosomal entry sites (IRESs) in their transcripts; IRESs hijack initiation factors for the assembly of initiation complexes. However, it is currently unknown how IRES RNAs recognize initiation factors that have no endogenous RNA binding partners; in a prominent example, the IRES of encephalomyocarditis virus (EMCV) interacts with the HEAT-1 domain of eukaryotic initiation factor 4G (eIF4G). Here we report the solution structure of the J-K region of this IRES and show that its stems are precisely organized to position protein-recognition bulges. This multisite interaction mechanism operates on an all-or-nothing principle in which all domains are required. This preorganization is accomplished by an 'adjuster module': a pentaloop motif that acts as a dual-sided docking station for base-pair receptors. Because subtle changes in the orientation abrogate protein capture, our study highlights how a viral RNA acquires affinity for a target protein.
PDB ID: 2NBXDownload
MMDB ID: 141992
PDB Deposition Date: 2016/3/16
Updated in MMDB: 2017/11
Experimental Method:
solution nmr
Source Organism:
Biological Unit for 2NBX: monomeric; determined by author
Molecular Components in 2NBX
Label Count Molecule
Nucleotide(1 molecule)
Ires RNA (108-mer)
Molecule annotation
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Citing MMDB