Deoxyhypusine Synthase Activity Is Essential for Cell Viability in the Yeast Saccharomyces cerevisiae

• Published in: The Journal of biological chemistry Vol. 273; no. 3; pp. 1677 - 1683
• Main Authors: Park, Myung Hee, Joe, Young Ae, Kang, Kee Ryeon
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 16.01.1998; American Society for Biochemistry and Molecular Biology
• Subjects: ACIDE AMINE; ACTIVIDAD ENZIMATICA; ACTIVITE ENZYMATIQUE; Alleles; Amino Acid Substitution; AMINO ACIDS; AMINOACIDOS; BINDING PROTEINS; Catalysis; Cell Cycle; Cell Survival; CRECIMIENTO; CROISSANCE; ENZYMIC ACTIVITY; EUKARYOTIC TRANSLATION INITIATION FACTOR; Eukaryotic Translation Initiation Factor 5A; FENOTIPOS; GENE; GENES; GROWTH; Humans; INDUCED MUTATION; LISINA; LYSINE; Lysine - metabolism; MUTACION; MUTACION INDUCIDA; Mutagenesis, Site-Directed; MUTANT; MUTANTES; MUTANTS; MUTATION; MUTATION PROVOQUEE; Oxidoreductases Acting on CH-NH Group Donors - genetics; Oxidoreductases Acting on CH-NH Group Donors - metabolism; Peptide Initiation Factors - metabolism; PHENOTYPE; PHENOTYPES; Polymerase Chain Reaction; PRECURSORS; PROTEINAS AGLUTINANTES; PROTEINE DE LIAISON; RNA-Binding Proteins; SACCHAROMYCES CEREVISIAE; Saccharomyces cerevisiae - cytology; Saccharomyces cerevisiae - enzymology; TARGETED MUTAGENESIS; TRANSFERASAS; TRANSFERASE; TRANSFERASES; VIABILIDAD; VIABILITE; VIABILITY; YDHS GENE
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.3.1677

Deoxyhypusine synthase catalyzes the first step in the posttranslational synthesis of an unusual amino acid, hypusine (Nε-(4-amino-2-hydroxybutyl)lysine), in the eukaryotic translation initiation factor 5A (eIF-5A) precursor protein. The null mutation in the single copy gene, yDHS, encoding deoxyhypusine synthase results in the loss of viability in the yeast Saccharomyces cerevisiae. Upon depletion of deoxyhypusine synthase, and consequently of eIF-5A, cessation of growth was accompanied by a marked enlargement of cells, suggesting a defect in cell cycle progression or in cell division. Two residues of the yeast enzyme, Lys308 and Lys350, corresponding to Lys287 and Lys329, respectively, known to be critical for the activity of the human enzyme, were targeted for site-directed mutagenesis. The chromosomal ydhs null mutation was complemented by the plasmid-borne yDHSwild-type gene, but not by mutated genes encoding inactive proteins, including that with Lys350 → Arg substitution or with substitutions at both Lys308 and Lys350. The mutated gene ydhs(K308R) encoding a protein with diminished activities (<1% of wild type) could support growth but only to a very limited extent. These findings provide strong evidence that the hypusine modification is indeed essential for the survival of S. cerevisiae and imply a vital function for eIF-5A in all eukaryotes.