2gpq
Cap-free structure of eIF4E suggests basis for its allosteric regulation
Structural highlights
FunctionIF4E_HUMAN Its translation stimulation activity is repressed by binding to the complex CYFIP1-FMR1 (By similarity). Recognizes and binds the 7-methylguanosine-containing mRNA cap during an early step in the initiation of protein synthesis and facilitates ribosome binding by inducing the unwinding of the mRNAs secondary structures. Component of the CYFIP1-EIF4E-FMR1 complex which binds to the mRNA cap and mediates translational repression. In the CYFIP1-EIF4E-FMR1 complex this subunit mediates the binding to the mRNA cap.[1] 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 PubMedThe activity of the eukaryotic translation initiation factor eIF4E is modulated through conformational response to its ligands. For example, eIF4G and eIF4E-binding proteins (4E-BPs) modulate cap affinity, and thus physiological activity of eIF4E, by binding a site distal to the 7-methylguanosine cap-binding site. Further, cap binding substantially modulates eIF4E's affinity for eIF4G and the 4E-BPs. To date, only cap-bound eIF4E structures were reported. In the absence of structural information on the apo form, the molecular underpinnings of this conformational response mechanism cannot be established. We report here the first cap-free eIF4E structure. Apo-eIF4E exhibits structural differences in the cap-binding site and dorsal surface relative to cap-eIF4E. Analysis of structure and dynamics of apo-eIF4E, and changes observed upon ligand binding, reveal a molecular basis for eIF4E's conformational response to these ligands. In particular, alterations in the S4-H4 loop, distal to either the cap or eIF4G binding sites, appear key to modulating these effects. Mutation in this loop mimics these effects. Overall, our studies have important implications for the regulation of eIF4E. Cap-free structure of eIF4E suggests a basis for conformational regulation by its ligands.,Volpon L, Osborne MJ, Topisirovic I, Siddiqui N, Borden KL EMBO J. 2006 Nov 1;25(21):5138-49. Epub 2006 Oct 12. PMID:17036047[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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