| Type: | PTM | Name: | Translation elongation factor, IF5A, hypusine site |
| Description: | Translation initiation factor 5A (IF-5A) was previously reported to be involved in the first step of peptide bond formation in translation; however more recent work implicates it as a universally conserved translation elongation factor [].eIF5A is a cofactor for the Rev and Rex transactivator proteins of human immunodeficiency virus-1 and T-cell leukaemia virus I, respectively [, , ]. IF-5A is the sole protein in eukaryotes and archaea to contain the unusual amino acid hypusine (Ne-(4-amino-2-hydroxybutyl)lysine) that is an absolute functional requirement. The first step in the post-translational modification of lysine to hypusine is catalyzed by the enzyme deoxyhypusine synthase, the structure of which has been reported. Hypusine is derived from lysine by the post-translational addition of a butylamino group (from spermidine) to the epsilon-amino group of lysine. The hypusine group is essential to the function of eIF-5A. A hypusine-containing protein has been found in archaebacteria such as Sulfolobus acidocaldariusor Methanocaldococcus jannaschii(Methanococcus jannaschii); this protein is highly similar to eIF-5A and could play a similar role in protein biosynthesis. The signature for eIF-5A is centred on the hypusine residue. The crystal structure of IF-5A from the archaeon Pyrobaculum aerophilumhas been determined to 1.75 A. Unmodified P. aerophilum IF-5A is found to be a beta structure with two domains and three separate hydrophobic cores. The lysine (Lys42) that is post-translationally modified by deoxyhypusine synthase is found at one end of the IF-5A molecule in a turn between beta strands beta4 and beta5; this lysine residue is freely solvent accessible. The C-terminal domain is found to be homologous to the cold-shock protein CspA of Escherichia coli, which has a well characterised RNA-binding fold, suggesting that IF-5A is involved in RNA binding []. | Short Name: | Trans_elong_IF5A_hypusine_site |
| GO Term | Gene Name |
|---|---|
| GO:0003723 | IPR019769 |
| GO:0003746 | IPR019769 |
| GO:0043022 | IPR019769 |
| GO:0006452 | IPR019769 |
| GO:0045901 | IPR019769 |
| GO:0045905 | IPR019769 |
| GO Term | Gene Name |
|---|---|
| GO:0003723 | IPR019769 |
| GO:0003746 | IPR019769 |
| GO:0043022 | IPR019769 |
| GO:0006452 | IPR019769 |
| GO:0045901 | IPR019769 |
| GO:0045905 | IPR019769 |
