pH-dependent and ligand induced conformational changes of eucaryotic protein synthesis initiation factor eIF-(iso)4F: A circular dichroism study Journal Article
| Authors: | Wang, Y.; Sha, M.; Ren, W. Y.; van Heerden, A.; Browning, K. S.; Goss, D. J. |
| Article Title: | pH-dependent and ligand induced conformational changes of eucaryotic protein synthesis initiation factor eIF-(iso)4F: A circular dichroism study |
| Abstract: | The structural features of wheat germ protein synthesis initiation factor eIF-(iso)4F, which has a cap binding protein as one of its two subunits, are unknown. In this study, circular dichroism (CD) spectra and secondary structure prediction were obtained for eIF-(iso)4F and its two subunits, p28 and p86. The α-helix content of eIF-(iso)4F changed from 42% at pH 6.3 to 15% at pH 7.6, the optimum pH for cap binding. The β-sheet content increased from 14% (pH 6.3) to 38% at pH 7.6. The CD spectra of the two subunits, p28 and p86 were also measured and analyzed. The separated subunits both had a higher α-helix content at pH 7.6 than the native protein, giving values of 60% and 34% α-helix for p28 and p86, respectively. Binding of the dinucleotide cap analog to p28 reduced the α-helix content to approximately 8% with an increase in the β sheet content from 10% to 37%. The conformational changes in eIF-(iso)4F upon binding with mRNA are dependent on cap or oligonucleotide structure. A conformation consisting of approximately the same α-helix and P-sheet content can be induced by ligands even at non-optimal pH values. This large conformational transition suggests eIF-(iso)4F binds nucleic acids by interaction of a β-sheet motif and that this conformational transition may have a regulatory role. |
| Keywords: | protein conformation; ph; in vitro study; rna-binding proteins; eukaryota; ligands; conformational transition; nucleic acid conformation; ligand binding; protein structure, secondary; hydrogen-ion concentration; circular dichroism; rna cap-binding proteins; wheat germ; initiation factor; peptide initiation factors; triticum aestivum; priority journal; article; triticum; eukaryotic initiation factor-1; eif-(iso)4f; ph dependence |
| Journal Title: | Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology |
| Volume: | 1297 |
| Issue: | 2 |
| ISSN: | 0167-4838 |
| Publisher: | Elsevier B.V. |
| Date Published: | 1996-10-17 |
| Start Page: | 207 |
| End Page: | 213 |
| Language: | English |
| DOI: | 10.1016/s0167-4838(96)00119-7 |
| PUBMED: | 8917623 |
| PROVIDER: | scopus |
| DOI/URL: | |
| Notes: | Article -- Export Date: 22 November 2017 -- Source: Scopus |
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