PDBsum entry: 1hu3

Translation

PDB id: 1hu3

Contents

Protein chain

204 a.a. *

Waters ×69

* Residue conservation analysis

PDB id:

1hu3

Name:

Translation

Title:

Middle domain of human eif4gii

Structure:

Eif4gii. Chain: a. Fragment: residues 745-1003. Synonym: eukaryotic initiation factor 4gii. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.

Biol. unit:

Trimer (from PQS)

Resolution:

2.37Å R-factor: 0.249 R-free: 0.295

Authors:

J.Marcotrigiano,I.Lomakin,T.V.Pestova,C.U.T.Hellen, N.Sonenberg,S.K.Burley

Key ref:

J.Marcotrigiano et al. (2001). A conserved HEAT domain within eIF4G directs assembly of the translation initiation machinery. Mol Cell, 7, 193-203. PubMed id: 11172724 DOI: 10.1016/S1097-2765(01)00167-8

Date:

03-Jan-01 Release date: 21-Feb-01

Protein chain

O43432  (IF4G3_HUMAN) -  Eukaryotic translation initiation factor 4 gamma 3

Seq: 1585 a.a.

Struc: 204 a.a.*

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

 Gene Ontology (GO) functional annotation 

• Biological process: RNA metabolic process (1 term)
• Biochemical function: binding (2 terms)

DOI no: 10.1016/S1097-2765(01)00167-8

Mol Cell 7:193-203 (2001)

PubMed id: 11172724

A conserved HEAT domain within eIF4G directs assembly of the translation initiation machinery.

J.Marcotrigiano, I.B.Lomakin, N.Sonenberg, T.V.Pestova, C.U.Hellen, S.K.Burley.

ABSTRACT

The X-ray structure of the phylogenetically conserved middle portion of human eukaryotic initiation factor (eIF) 4GII has been determined at 2.4 A resolution, revealing a crescent-shaped domain consisting of ten alpha helices arranged as five HEAT repeats. Together with the ATP-dependent RNA helicase eIF4A, this HEAT domain suffices for 48S ribosomal complex formation with a picornaviral RNA internal ribosome entry site (IRES). Structure-based site-directed mutagenesis was used to identify two adjacent features on the surface of this essential component of the translation initiation machinery that, respectively, bind eIF4A and a picornaviral IRES. The structural and biochemical results provide mechanistic insights into both cap-dependent and cap-independent translation initiation.

Selected figure(s)

Figure 2.
Figure 2. Structural and Functional Characterization of the eIF4A/IRES Binding Domain of Human eIF4G(A) Structure-based sequence alignments of the eIF4A/IRES binding domains of all known eIF4Gs and eIF4G-related proteins, including human eIF4GII ([21]) (used in structure determination), human eIF4GI ( [29]), Saccharomyces cerevisiae TIF4631 and TIF4632 ([20]), Triticum aestivum eIF-(iso)4G ( [1]), human p97 ( [28]), and human Paip-1 ( [10]). α-helical secondary structural elements are denoted with cylinders and labeled with repeat number and a or b. Dashed lines correspond to regions with poorly resolved electron density. Color scheme: red, identity; blue, high conservation. V8 protease cleavage sites are denoted by arrows. Location of eIF4G mutants: (1), M-1 ([27]); (4), M-4 ( [27]); (7), mut(Ile749→Thr, Arg754→Ile) ( [37]); (8), mut796-Ins8 ( [37]); (R), RRM1 ( [37]); (t), tif4632–6 ( [43]); (A), reduced eIF4A binding, 756; (K), reduced IRES binding, 834; (B), reduced eIF4A and IRES binding, 814; (N), no effect, 798, 802, 803, 843, and 888. (See Table 2 for a complete description of eIF4G mutations.)(B) Toeprint analyses of the interaction of eIF4GII (extended construct: 735–1097 and crystallization construct: 745–1003) with the EMCV IRES in the presence and absence of eIF4A. The full-length cDNA extension product is marked (e). A common stop site within the EMCV RNA used as an internal normalization standard is denoted by (N). The stop site due to binding of eIF4GII is indicated by (C786). Reference lanes (t), (c), (g), and (a) depict the EMCV IRES cDNA sequence.

Figure 3.
Figure 3. Structure of the eIF4A/IRES Binding Domain of eIF4GII(A) Ribbon stereodrawing of the conserved central region of eIF4GII viewed along the cylindrical axes of the α helices, with the concave surface on the right and the convex surface on the left. α helices are labeled as in Figure 2A.(B) Stereodrawing viewed perpendicular to the α helix axes, rotated 90° about the solenoid axis relative to (A), with the concave surface in the foreground. The intra- and interrepeat surfaces are located on the right and left, respectively.(C) Stereodrawing viewed along the α-helix axes, rotated 180° about the solenoid axis relative to A, with the intrarepeat surface in the foreground and the concave and convex surfaces on the left and right, respectively.

The above figures are reprinted by permission from Cell Press: Mol Cell (2001, 7, 193-203) copyright 2001.

Figures were selected by an automated process.