Structure of the beta subunit of translational initiation factor eIF-2.
A human liver cDNA encoding the beta subunit of protein synthesis initiation factor 2 (eIF-2) was isolated and sequenced. The 1416 bp cDNA encodes a protein of 333 amino acids (38,404 daltons) with characteristics that resemble authentic purified eIF-2 beta. De novo synthesized eIF-2 beta from cDNA transcripts incorporates into endogenous rabbit eIF-2 complexes. The protein possesses putative GTP-binding sites, a zinc finger motif, and a highly charged N-terminal region composed of three basic polylysine blocks separated by acidic domains. The polylysine blocks and the zinc finger motif suggest that eIF-2 beta interacts with RNA. A yeast protein, Sui3, isolated as an extragenic suppressor of his4 initiation codon mutations, exhibits extensive sequence identity with human eIF-2 beta, especially in the polylysine and zinc finger domains, thereby reinforcing the view that these elements are important for function.
D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015852:Eukaryotic Initiation Factor-2; D005796:Genes; D005800:Genes, Fungal; D006801:Humans; D046911:Macromolecular Substances; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D010448:Peptide Initiation Factors / Q000235:genetics*; D011506:Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
D015852:Eukaryotic Initiation Factor-2; D046911:Macromolecular Substances; D010448:Peptide Initiation Factors; D011506:Proteins; D004247:DNA