Characterization of the ATP-dependent binding of wheat germ protein synthesis initiation factors eIF-(iso)4F and eIF-4A to mRNA.
The ATP-dependent binding of wheat germ protein synthesis initiation factors eIF-(iso)4F and eIF-4A to an oligoribonucleotide has been investigated by direct fluorescence titration techniques. In addition, the effect of ATP on the interaction between another cap-binding initiation factor, eIF-4F, and eIF-4A was studied using the same methods. Comparison of the equilibrium association constants (K(eq)) indicate that 1) hydrolyzable ATP affects the affinity of eIF-(iso)4F for eIF-4A, regardless of whether or not mRNA was previously bound to the eIF-(iso)4F; in contrast, ATP had no effect on the eIF-(iso)4F/oligoribonucleotide interaction; 2) in the presence of ATP, the binding of the binary eIF-(iso)4F.eIF-4A complex to the oligoribonucleotide is of similar affinity as the binding of the oligoribonucleotide to the eIF-(iso)4F alone; the stoichiometry of this ternary eIF-(iso)4F.eIF-4A.mRNA complex was found to be 1:1:1; and 3) a similar ATP effect is observed for the eIF-4F/eIF-4A interaction as for the eIF-(iso)4F.eIF-4A complex.
Balasta
M L
ML
Department of Chemistry, Hunter College, City University of New York, New York 10021-5024.
Carberry
S E
SE
Friedland
D E
DE
Perez
R A
RA
Goss
D J
DJ
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000266:Adenylyl Imidodiphosphate / Q000494:pharmacology; D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D039601:Eukaryotic Initiation Factor-4A; D039562:Eukaryotic Initiation Factor-4F; D016650:Fluorescein-5-isothiocyanate; D005456:Fluorescent Dyes; D008969:Molecular Sequence Data; D009843:Oligoribonucleotides / Q000737:chemistry / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014908:Triticum / Q000737:chemistry*
D039562:Eukaryotic Initiation Factor-4F; D005456:Fluorescent Dyes; D009843:Oligoribonucleotides; D010448:Peptide Initiation Factors; D012333:RNA, Messenger; D000266:Adenylyl Imidodiphosphate; D000255:Adenosine Triphosphate; D039601:Eukaryotic Initiation Factor-4A; D016650:Fluorescein-5-isothiocyanate