A comparison of the binding of methylated cap analogues to wheat germ protein synthesis initiation factors 4F and (iso)4F.
The binding of the 5'-terminal cap analogues m7GpppG and m7GTP to wheat germ protein synthesis initiation factors eIF-4F and eIF-(iso)4F as a function of pH, ionic strength, and temperature is described. Equilibrium binding data indicate that eIF-4F and eIF-(iso)4F have different mechanisms for interacting with the 5'-cap structure, but the complexes formed between m7GpppG and wheat germ factor eIF-(iso)4F more closely resemble complexes formed between this cap analogue and either mammalian eIF-4E or eIF-4F. The binding of these initiation factors to the hypermethylated cap analogues m2,7GMP, m2,7GpppG, and m2,2,7GpppG is also investigated. The differences in affinity of eIF-4F and eIF-(iso)4F for the hypermethylated 5'-terminal cap structures suggest that these factors may have discriminatory activity.
Carberry
S E
SE
Department of Chemistry, Hunter College of the City University of New York, New York 10021.
Darzynkiewicz
E
E
Goss
D J
DJ
D039562:Eukaryotic Initiation Factor-4F; D006150:Guanine Nucleotides / Q000378:metabolism*; D006160:Guanosine Triphosphate / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008745:Methylation; D010448:Peptide Initiation Factors / Q000378:metabolism*; D011189:Potassium Chloride / Q000494:pharmacology; D011485:Protein Binding; D012315:RNA Caps / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014908:Triticum / Q000378:metabolism*
D039562:Eukaryotic Initiation Factor-4F; D006150:Guanine Nucleotides; D010448:Peptide Initiation Factors; D012315:RNA Caps; D011189:Potassium Chloride; D006160:Guanosine Triphosphate