Translation elongation factor eIF-5A; required for translation of proteins with polyproline stretches; hypusination promotes translation elongation, termination and ribosomal frameshifting; localizes to the nucleus and binds chromatin to repress transcription; structural homolog of bacterial EF-P; human EIF5A variants cause a disorder with variable combinations of developmental delay, microcephaly, micrognathia and dysmorphism; human EIF5A complements inviability of a hyp2 anb1 double null