3CPF, 5DLQ1984276770ENSG00000132507ENSG00000288145ENSMUSG00000078812P63241P63242NM_001370421NM_001166594NM_001166595NM_001166596NM_181582NP_001357350NP_001160066NP_001160067NP_001160068NP_853613Eukaryotic translation initiation factor 5A-1 is a protein that in humans is encoded by the EIF5A gene.

[5] It is the only known protein to contain the unusual amino acid hypusine [Nε-(4-amino-2-hydroxybutyl)-lysine], which is synthesized on eIF5A at a specific lysine residue from the polyamine spermidine by two catalytic steps.

[6] EF-P is the bacterial homolog of eIF5A, which is modified post-translationally in a similar but distinct way.

[7][8] Both proteins are believed to catalyze peptide bond formation and help resolve ribosomal stalls, making them elongation factors despite the "initiation factor" name originally assigned.

[10][11] This rare human disorder is characterized by variable combinations of developmental delay, microcephaly, micrognathia and dysmorphic features.