1L8B

Cocrystal Structure of the Messenger RNA 5' Cap-binding Protein (eIF4E) bound to 7-methylGpppG

Summary for 1L8B

• Entry DOI: 10.2210/pdb1l8b/pdb
• Descriptor: EUKARYOTIC TRANSLATION INITIATION FACTOR 4E, 7-METHYL-GUANOSINE-5'-TRIPHOSPHATE (3 entities in total)
• Functional Keywords: eukaryotic initiation factor 4e, eif4e, cap, 7-methylgpppg, rna binding protein
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 2
• Total formula weight: 45366.66

Authors

Niedzwiecka, A.,Marcotrigiano, J.,Stepinski, J.,Jankowska-Anyszka, M.,Wyslouch-Cieszynska, A.,Dadlez, M.,Gingras, A.-C.,Mak, P.,Darzynkiewicz, E.,Sonenberg, N. (deposition date: 2002-03-19, release date: 2002-06-12, Last modification date: 2024-02-14)

Primary citation

Niedzwiecka, A.,Marcotrigiano, J.,Stepinski, J.,Jankowska-Anyszka, M.,Wyslouch-Cieszynska, A.,Dadlez, M.,Gingras, A.C.,Mak, P.,Darzynkiewicz, E.,Sonenberg, N.,Burley, S.K.,Stolarski, R.
Biophysical studies of eIF4E cap-binding protein: recognition of mRNA 5' cap structure and synthetic fragments of eIF4G and 4E-BP1 proteins.
J.Mol.Biol., 319:615-635, 2002

PubMed Abstract: mRNA 5'-cap recognition by the eukaryotic translation initiation factor eIF4E has been exhaustively characterized with the aid of a novel fluorometric, time-synchronized titration method, and X-ray crystallography. The association constant values of recombinant eIF4E for 20 different cap analogues cover six orders of magnitude; with the highest affinity observed for m(7)GTP (approximately 1.1 x 10(8) M(-1)). The affinity of the cap analogues for eIF4E correlates with their ability to inhibit in vitro translation. The association constants yield contributions of non-covalent interactions involving single structural elements of the cap to the free energy of binding, giving a reliable starting point to rational drug design. The free energy of 7-methylguanine stacking and hydrogen bonding (-4.9 kcal/mol) is separate from the energies of phosphate chain interactions (-3.0, -1.9, -0.9 kcal/mol for alpha, beta, gamma phosphates, respectively), supporting two-step mechanism of the binding. The negatively charged phosphate groups of the cap act as a molecular anchor, enabling further formation of the intermolecular contacts within the cap-binding slot. Stabilization of the stacked Trp102/m(7)G/Trp56 configuration is a precondition to form three hydrogen bonds with Glu103 and Trp102. Electrostatically steered eIF4E-cap association is accompanied by additional hydration of the complex by approximately 65 water molecules, and by ionic equilibria shift. Temperature dependence reveals the enthalpy-driven and entropy-opposed character of the m(7)GTP-eIF4E binding, which results from dominant charge-related interactions (DeltaH degrees =-17.8 kcal/mol, DeltaS degrees= -23.6 cal/mol K). For recruitment of synthetic eIF4GI, eIF4GII, and 4E-BP1 peptides to eIF4E, all the association constants were approximately 10(7) M(-1), in decreasing order: eIF4GI>4E-BP1>eIF4GII approximately 4E-BP1(P-Ser65) approximately 4E-BP1(P-Ser65/Thr70). Phosphorylation of 4E-BP1 at Ser65 and Thr70 is insufficient to prevent binding to eIF4E. Enhancement of the eIF4E affinity for cap occurs after binding to eIF4G peptides.

PubMed: 12054859
DOI: 10.1016/S0022-2836(02)00328-5

Experimental method

X-RAY DIFFRACTION (1.8 Å)