Site-directed mutagenesis of the tryptophan residues in yeast eukaryotic initiation factor 4E. Effects on cap binding activity.
Initiation factor 4E is a 24-kilodalton polypeptide that binds specifically to the 5' cap structure of eukaryotic mRNAs. Sequence analysis of cDNA clones of initiation factor 4E from several species revealed a high tryptophan content (8 residues). Strikingly, all tryptophans are conserved evolutionarily in number and position between yeast and mammals. Here we show, using site-directed mutagenesis, that two of the tryptophans (those referred to as numbers 1 and 8) are absolutely required for the cap binding activity of an Escherichia coli expressed initiation factor 4E.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics; D039561:Eukaryotic Initiation Factor-4E; D005796:Genes; D005800:Genes, Fungal; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D010448:Peptide Initiation Factors / Q000235:genetics* / Q000378:metabolism; D012315:RNA Caps / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D014158:Transcription, Genetic; D014364:Tryptophan
D039561:Eukaryotic Initiation Factor-4E; D015345:Oligonucleotide Probes; D010448:Peptide Initiation Factors; D012315:RNA Caps; D014364:Tryptophan