title: Solution-based approach to study binding to the eIF4E cap-binding site using CD spectroscopy.
abstract: The eukaryotic initiation factor 4E (eIF4E) is the key component of the translational initiation complex that recruits mRNA by binding to a unique "cap" structure located at the 5' end of the mRNA. Overexpression of eIF4E has been implicated in the development of cancer, potentially as a result of increasing the cellular levels of proteins involved in processes that include proliferation and regulation of apoptosis. As a result, the cap-binding site of eIF4E has become a target for the development of anti-cancer therapeutics. The structure of eIF4E bound to the cap mimic 7-methyl-GDP revealed that two tryptophans from different loops in eIF4E sandwiched the 7-methylguanine group between them. This interaction gives rise to a strong exciton coupling signal between the two tryptophans that can be visualized by CD spectroscopy. eIF4E is a challenging protein to work with because of a propensity to aggregate under conditions used in biophysical techniques. CD spectroscopy provides a gentle, solution-based approach to study binding to the cap-binding site of eIF4E. Evidence is provided that the exciton coupling signal can be used to both qualitatively and quantitatively analyze the binding of cap analogs to eIF4E.
authors.affiliation: Discovery Technology, Hoffmann-La Roche Inc., 340 Kingsland Street, Nutley, NJ 07110, USA. colin.garvie@gmail.com
authors.forename: Colin W
authors.initials: CW
authors.lastname: Garvie
mesh_terms: D001665:Binding Sites; D002942:Circular Dichroism; D039561:Eukaryotic Initiation Factor-4E / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006153:Guanosine Diphosphate / Q000031:analogs & derivatives / Q000737:chemistry / Q000378:metabolism; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D058849:Protein Refolding; D017434:Protein Structure, Tertiary; D012314:RNA Cap Analogs / Q000737:chemistry / Q000378:metabolism; D012315:RNA Caps / Q000737:chemistry / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics; D012254:Ribavirin / Q000737:chemistry / Q000378:metabolism; D012996:Solutions / Q000737:chemistry
chemical_list: D039561:Eukaryotic Initiation Factor-4E; D009711:Nucleotides; D012314:RNA Cap Analogs; D012315:RNA Caps; D011994:Recombinant Proteins; D012996:Solutions; C111106:7-methylguanosine 5'-diphosphate; D006153:Guanosine Diphosphate; D012254:Ribavirin; C037827:ribavirin 5'-triphosphate