7KMA image
Entry Detail
PDB ID:
7KMA
Title:
Crystal structure of eif2Balpha with a ligand.
Biological Source:
Source Organism:
Host Organism:
PDB Version:
Deposition Date:
2020-11-02
Release Date:
2021-07-21
Method Details:
Experimental Method:
Resolution:
2.70 Å
R-Value Free:
0.23
R-Value Work:
0.19
R-Value Observed:
0.19
Space Group:
P 1 21 1
Macromolecular Entities
Polymer Type:polypeptide(L)
Description:Translation initiation factor eIF-2B subunit alpha
Chain IDs:A, B, C, D, E, F, G, H
Chain Length:313
Number of Molecules:8
Biological Source:Homo sapiens
Primary Citation
Sugar phosphate activation of the stress sensor eIF2B.
Nat Commun 12 3440 3440 (2021)
PMID: 34103529 DOI: 10.1038/s41467-021-23836-z

Abstact

The multi-subunit translation initiation factor eIF2B is a control node for protein synthesis. eIF2B activity is canonically modulated through stress-responsive phosphorylation of its substrate eIF2. The eIF2B regulatory subcomplex is evolutionarily related to sugar-metabolizing enzymes, but the biological relevance of this relationship was unknown. To identify natural ligands that might regulate eIF2B, we conduct unbiased binding- and activity-based screens followed by structural studies. We find that sugar phosphates occupy the ancestral catalytic site in the eIF2Bα subunit, promote eIF2B holoenzyme formation and enhance enzymatic activity towards eIF2. A mutant in the eIF2Bα ligand pocket that causes Vanishing White Matter disease fails to engage and is not stimulated by sugar phosphates. These data underscore the importance of allosteric metabolite modulation for proper eIF2B function. We propose that eIF2B evolved to couple nutrient status via sugar phosphate sensing with the rate of protein synthesis, one of the most energetically costly cellular processes.

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