Deoxyhypusine synthase gene is essential for cell viability in the yeast Saccharomyces cerevisiae

Deoxyhypusine synthase catalyzes the first of two steps in the biosynthesis of hypusine, a modification of a specific lysine residue in the precursor of eukaryotic translation initiation factor 5A. We have purified deoxyhypusine synthase from yeast, and cloned and sequenced the corresponding gene encoding a 387-amino acid protein from Saccharomyces cerevisiae. Gene disruption experiments indicated that the deoxyhypusine synthase gene is essential for cell growth in yeast. This gene was shown to be an intron-free, single-copy gene, and its product can catalyze the synthesis of deoxyhypusine equally in two precursor forms of eIF-5A, derived from two distinct genes of yeast.