PDBsum entry 2idv

Translation regulator

PDB id: 2idv

Contents

Protein chain

177 a.a. *

Ligands

M7G

Waters ×101

* Residue conservation analysis

PDB id:

2idv

Name:

Translation regulator

Title:

Crystal structure of wheat c113s mutant eif4e bound to 7-methyl-gdp

Structure:

Eukaryotic translation initiation factor 4e-1. Chain: a. Fragment: residues 39-215. Synonym: eif4e-1, eif-4e-1, mRNA cap-binding protein, eif-4f 25 kda subunit, eif-4f p26 subunit. Engineered: yes. Mutation: yes

Source:

Triticum aestivum. Bread wheat. Organism_taxid: 4565. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.30Å R-factor: 0.200 R-free: 0.274

Authors:

A.F.Monzingo,A.Dutt-Chaudhuri,J.Sadow,S.Dhaliwal,D.W.Hoffman, J.D.Robertus,K.S.Browning

Key ref:

A.F.Monzingo et al. (2007). The structure of eukaryotic translation initiation factor-4E from wheat reveals a novel disulfide bond. Plant Physiol, 143, 1504-1518. PubMed id: 17322339

Date:

15-Sep-06 Release date: 12-Jun-07

Protein chain

P29557  (IF4E1_WHEAT) -  Eukaryotic translation initiation factor 4E-1 from Triticum aestivum

Seq: 215 a.a.

Struc: 177 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

Plant Physiol 143:1504-1518 (2007)

PubMed id: 17322339

The structure of eukaryotic translation initiation factor-4E from wheat reveals a novel disulfide bond.

A.F.Monzingo, S.Dhaliwal, A.Dutt-Chaudhuri, A.Lyon, J.H.Sadow, D.W.Hoffman, J.D.Robertus, K.S.Browning.

ABSTRACT

Eukaryotic translation initiation factor-4E (eIF4E) recognizes and binds the m(7) guanosine nucleotide at the 5' end of eukaryotic messenger RNAs; this protein-RNA interaction is an essential step in the initiation of protein synthesis. The structure of eIF4E from wheat (Triticum aestivum) was investigated using a combination of x-ray crystallography and nuclear magnetic resonance (NMR) methods. The overall fold of the crystallized protein was similar to eIF4E from other species, with eight beta-strands, three alpha-helices, and three extended loops. Surprisingly, the wild-type protein did not crystallize with m(7)GTP in its binding site, despite the ligand being present in solution; conformational changes in the cap-binding loops created a large cavity at the usual cap-binding site. The eIF4E crystallized in a dimeric form with one of the cap-binding loops of one monomer inserted into the cavity of the other. The protein also contained an intramolecular disulfide bridge between two cysteines (Cys) that are conserved only in plants. A Cys-to-serine mutant of wheat eIF4E, which lacked the ability to form the disulfide, crystallized with m(7)GDP in its binding pocket, with a structure similar to that of the eIF4E-cap complex of other species. NMR spectroscopy was used to show that the Cys that form the disulfide in the crystal are reduced in solution but can be induced to form the disulfide under oxidizing conditions. The observation that the disulfide-forming Cys are conserved in plants raises the possibility that their oxidation state may have a role in regulating protein function. NMR provided evidence that in oxidized eIF4E, the loop that is open in the ligand-free crystal dimer is relatively flexible in solution. An NMR-based binding assay showed that the reduced wheat eIF4E, the oxidized form with the disulfide, and the Cys-to-serine mutant protein each bind m(7)GTP in a similar and labile manner, with dissociation rates in the range of 20 to 100 s(-1).