7NWT • cryo-EM
EMCV 2A protein in complex with initiated 70S ribosomes
The cryo-EM structure shows how EMCV 2A binds directly to the small ribosome subunit via direct interactions between the 2A "arginine loop" and 16S rRNA. Binding at this site would clash with translational GTPases, suggesting a potential explanation for the observed translational inhibition in the presence of 2A.
7BNY • X-ray crystallography
EMCV 2A protein
The crystal structure of 2A protein from encephalomyocarditis virus (EMCV) revealed a new RNA-binding fold. Interestingly, the asymmetric unit of these crystals contained four molecules with a very unusual arrangement - intermolecular disulfide bonds had formed between surface-exposed cysteine residues (yellow spheres). The "arginine loop" residues that are essential for RNA binding and frameshifting are also highlighted as spheres.
7NBV • X-ray crystallography
TMEV 2A protein
This crystal structure of 2A from related cardiovirus Theiler's murine encephalomyelitis virus (TMEV) showed that it adopts a similar 'beta-shell' fold to the EMCV orthologue, despite sharing < 20 % sequence identity. The "arginine loop" (shown as spheres) is the most conserved feature, and mechanisms of RNA recognition are likely similar.