8T7T

CryoEM structure of the HisRS-like domain of human GCN2

Summary for 8T7T

• Entry DOI: 10.2210/pdb8t7t/pdb
• EMDB information: 41094
• Descriptor: eIF-2-alpha kinase GCN2 (1 entity in total)
• Functional Keywords: gcn2, hisrs, pseudoenzyme, translation, transferase
• Biological source: Homo sapiens (human)
• Total number of polymer chains: 2
• Total formula weight: 374433.16

Authors

Yin, J.Z.,Keszei, A.F.A.,Mazhab-Jafari, M.T.,Sicheri, F. (deposition date: 2023-06-21, release date: 2024-03-13, Last modification date: 2024-09-25)

Primary citation

Yin, J.Z.,Keszei, A.F.A.,Houliston, S.,Filandr, F.,Beenstock, J.,Daou, S.,Kitaygorodsky, J.,Schriemer, D.C.,Mazhab-Jafari, M.T.,Gingras, A.C.,Sicheri, F.
The HisRS-like domain of GCN2 is a pseudoenzyme that can bind uncharged tRNA.
Structure, 32:795-811.e6, 2024

PubMed Abstract: GCN2 is a stress response kinase that phosphorylates the translation initiation factor eIF2α to inhibit general protein synthesis when activated by uncharged tRNA and stalled ribosomes. The presence of a HisRS-like domain in GCN2, normally associated with tRNA aminoacylation, led to the hypothesis that eIF2α kinase activity is regulated by the direct binding of this domain to uncharged tRNA. Here we solved the structure of the HisRS-like domain in the context of full-length GCN2 by cryoEM. Structure and function analysis shows the HisRS-like domain of GCN2 has lost histidine and ATP binding but retains tRNA binding abilities. Hydrogen deuterium exchange mass spectrometry, site-directed mutagenesis and computational docking experiments support a tRNA binding model that is partially shifted from that employed by bona fide HisRS enzymes. These results demonstrate that the HisRS-like domain of GCN2 is a pseudoenzyme and advance our understanding of GCN2 regulation and function.

PubMed: 38531363
DOI: 10.1016/j.str.2024.02.021

Experimental method

ELECTRON MICROSCOPY (3.2 Å)