1paq

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CRYSTAL STRUCTURE OF THE CATALYTIC FRAGMENT OF EUKARYOTIC INITIATION FACTOR 2B EPSILON

Structural highlights

1paq is a 1 chain structure with sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Method:X-ray diffraction, Resolution 2.3Å
Ligands:MSE
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

EI2BE_YEAST Acts as a catalytic component of the translation initiation factor 2B (eIF2-B or GCD complex), which catalyzes the exchange of eukaryotic initiation factor 2 (eIF-2)-bound GDP for GTP and is regulated by phosphorylated eIF-2. It activates the synthesis of GCN4 in yeast under amino acid starvation conditions by suppressing the inhibitory effects of multiple AUG codons present in the leader of GCN4 mRNA. It may promote either repression or activation of GCN4 expression depending on amino acid availability. GCD6 and GCD7 repress GCN4 expression at the translational level by ensuring that ribosomes which have translated UORF1 will reinitiate at UORF2, -3, or -4 and thus fail to reach the GCN4 start site.[1] [2]

Evolutionary Conservation

Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.

Publication Abstract from PubMed

Eukaryotic initiation factor (eIF) 2B catalyzes the nucleotide activation of eIF2 to its active GTP-bound state. The exchange activity has been mapped to the C terminus of the eIF2Bepsilon subunit. We have determined the crystal structure of residues 544-704 from yeast eIF2Bepsilon at 2.3-A resolution, and this fragment is an all-helical protein built around the conserved aromatic acidic (AA) boxes also found in eIF4G and eIF5. The eight helices are organized in a manner similar to HEAT repeats. The molecule is highly asymmetric with respect to surface charge and conservation. One area in the N terminus is proposed to be directly involved in catalysis. In agreement with this hypothesis, mutation of glutamate 569 is shown to be lethal. An acidic belt and a second area in the C terminus containing residues from the AA boxes are important for binding to eIF2. Two mutations causing the fatal human genetic disease leukoencephalopathy with vanishing white matter are buried and appear to disrupt the structural integrity of the catalytic domain rather than interfering directly with catalysis or binding of eIF2.

Structure of the catalytic fragment of translation initiation factor 2B and identification of a critically important catalytic residue.,Boesen T, Mohammad SS, Pavitt GD, Andersen GR J Biol Chem. 2004 Mar 12;279(11):10584-92. Epub 2003 Dec 17. PMID:14681227[3]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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See Also

References

  1. ↑ Cigan AM, Bushman JL, Boal TR, Hinnebusch AG. A protein complex of translational regulators of GCN4 mRNA is the guanine nucleotide-exchange factor for translation initiation factor 2 in yeast. Proc Natl Acad Sci U S A. 1993 Jun 1;90(11):5350-4. PMID:8506384
  2. ↑ Pavitt GD, Ramaiah KV, Kimball SR, Hinnebusch AG. eIF2 independently binds two distinct eIF2B subcomplexes that catalyze and regulate guanine-nucleotide exchange. Genes Dev. 1998 Feb 15;12(4):514-26. PMID:9472020
  3. ↑ Boesen T, Mohammad SS, Pavitt GD, Andersen GR. Structure of the catalytic fragment of translation initiation factor 2B and identification of a critically important catalytic residue. J Biol Chem. 2004 Mar 12;279(11):10584-92. Epub 2003 Dec 17. PMID:14681227 doi:10.1074/jbc.M311055200

Contents


PDB ID 1paq

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