Tryptophan Residues from Cap Binding Slot in eIF4E Family Members: Their Contributions to Near-UV Circular Dichroism Spectra
Joanna Zuberek* and Agnieszka Stelmachowska
Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, Warsaw, 02-089, Poland
- *Corresponding Author:
- Joanna Zuberek
Division of Biophysics, Institute of Experimental Physics
Faculty of Physics, University of Warsaw
Zwirki i Wigury 9302-089 Warsaw, Poland
E-mail: [email protected]
Received Date: June 22, 2017 Accepted Date: June 26, 2017 Published Date: June 30, 2017
Citation: Zuberek J, Stelmachowska A (2017) Tryptophan Residues from Cap Binding Slot in eIF4E Family Members: Their Contributions to Near-UV Circular Dichroism Spectra. J Phys Chem Biophys 7: 250. doi: 10.4172/2161-0398.1000250
Copyright: © 2017 Zuberek J, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
eIF4E, a key factor in the cap-dependent translation initiation, binds cap structure at the 5’ end of mRNA by stacking interaction involving two of its eight conserved tryptophan residues. In this paper, we examined individual contributions of tryptophan residues to the near-UV Circular Dichroism spectra to identify structural similarities and differences in cap binding motif among members of eIF4E family. The near-UV CD spectrum of human eIF4E1a in its apo form, resulting mainly from 1Lb transition and dominated by two vibrionic bands, is conserved among eIF4Es. Based on comparison of CD spectra for eIF4E mutants, we showed that tryptophans involved in stacking interaction give strongest individual contributions, which allow identification of their different orientation with respect to the cap. This indicates that near-UV CD is a quick and powerful tool to analyse tryptophan conformation in eIF4E proteins, and their changes upon binding modified cap analogues.