A lysine substitution in the ATP-binding site of eucaryotic initiation factor 4A abrogates nucleotide-binding activity.
Eucaryotic initiation factor 4A (eIF-4A) is a member of a family of proteins believed to be involved in the ATP-dependent melting of RNA secondary structure. These proteins contain a derivative of the consensus ATP-binding site AXXGXGKT. To assess the importance of the consensus amino acid sequence in eIF-4A for ATP binding, we mutated the consensus amino-proximal glycine and lysine to isoleucine and asparagine, respectively. The effect of the mutations was examined by UV-induced cross-linking of [alpha-32P]dATP to eIF-4A. Mutation of the lysine residue (but not of the glycine residue) resulted in the loss of [alpha-32P]dATP cross-linking to eIF-4A, suggesting that the lysine is an important determinant in ATP binding to eIF-4A.
Rozen
F
F
Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
Pelletier
J
J
Trachsel
H
H
Sonenberg
N
N
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D039601:Eukaryotic Initiation Factor-4A; D066298:In Vitro Techniques; D008239:Lysine; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D009711:Nucleotides / Q000378:metabolism; D010448:Peptide Initiation Factors / Q000235:genetics / Q000378:metabolism*
D009711:Nucleotides; D010448:Peptide Initiation Factors; D000255:Adenosine Triphosphate; D039601:Eukaryotic Initiation Factor-4A; D008239:Lysine