Identification and functional analysis of the Saccharomyces cerevisiae nicotinamidase gene, PNC1.
Nicotinamidase (NAMase) from the budding yeast, Saccharomyces cerevisiae, was purified by Ni(2+) affinity chromatography and gel filtration. N-terminal microsequencing revealed sequence identity with a hypothetical polypeptide encoded by the yeast YGL037C open reading frame sharing 30% sequence identity with Escherichia coli pyrazinamidase/nicotinamidase. A yeast strain in which the NAMase gene, hereafter named PNC1, was deleted shows a decreased intracellular NAD(+) concentration, consistent with the loss of NAMase activity in the null mutant. In wild-type strains, NAMase activity is stimulated during the stationary phase of growth, by various hyperosmotic shocks or by ethanol treatment. Using a P(PNC1)::lacZ gene fusion, we have shown that this stimulation of NAMase activity results from increased levels of the protein and requires stress response elements in the 5'non-coding region of PNC1. These results suggest that NAMase helps yeast cells to adapt to various stress conditions and nutrient depletion, most likely via the activation of NAD-dependent biological processes.
Ghislain
Michel
M
Unité de Biochimie Physiologique, Université Catholique de Louvain, Croix du Sud 2-20, B-1348 Louvain-la-Neuve, Belgium. ghislain@fysa.ucl.ac.be
Talla
Emmanuel
E
François
Jean M
JM
D000581:Amidohydrolases / Q000032:analysis; D000595:Amino Acid Sequence; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification; D008969:Molecular Sequence Data; D009154:Mutation; D009243:NAD / Q000032:analysis; D009535:Nicotinamidase / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D012441:Saccharomyces cerevisiae / Q000201:enzymology / Q000235:genetics*; D017386:Sequence Homology, Amino Acid
D004271:DNA, Fungal; D009243:NAD; D000581:Amidohydrolases; C022490:pyrazinamide deamidase; D009535:Nicotinamidase