title: Cloning, sequencing and characterization of a gene encoding dihydroxyacetone kinase from Zygosaccharomyces rouxii NRRL2547.
abstract: The dihydroxyacetone pathway, an alternative pathway for the dissimilation of glycerol via reduction by glycerol dehydrogenase and subsequent phosphorylation by dihydroxyacetone (DHA) kinase, is activated in the yeasts Saccharomyces cerevisiae and Zygosaccharomyces rouxii during osmotic stress. In experiments aimed at investigating the physiological function of the DHA pathway in Z. rouxii, a typical osmotolerant yeast, we cloned and characterized a DAK gene encoding dihydroxyacetone kinase from Z. rouxii NRRL 2547. Sequence analysis revealed a 1761 bp open reading frame, encoding a peptide composed of 587 deduced amino acids with the predicted molecular weight of 61 664 Da. As the amino acid sequence was most closely homologous (68% identity) to the S. cerevisiae Dak1p, we named the gene and protein ZrDAK1 and ZrDak1p, respectively. A putative ATP binding site was also found but no consensus element associated with osmoregulation was found in the upstream region of the ZrDAK1 gene. The ZrDAK1 gene complemented a S. cerevisiae W303-1A dak1delta dak2 delta strain by improving the growth of the mutant on 50 mmol/l dihydroxyacetone and by increasing the tolerance to dihydroxyacetone in a medium containing 5% sodium chloride, suggesting that it is a functional homologue of the S. cerevisiae DAK1. However, expression of the ZrDAK1 gene in the S. cerevisiae dak1delta dak2 delta strain had no significant effect on glycerol levels during osmotic stress. The ZrDAK1 sequence has been deposited in the public data bases under Accession No. AJ294719; regions upstream and downstream of ZrDAK1are deposited as Accession Nos AJ294739 and AJ294720, respectively.
authors.affiliation: Department of Microbiology, University of Stellenbosch, Private Bag X1, 7602 Matieland, South Africa.
authors.forename: Zheng-Xiang
authors.initials: ZX
authors.lastname: Wang
authors.forename: Gerald
authors.initials: G
authors.lastname: Kayingo
authors.forename: Anders
authors.initials: A
authors.lastname: Blomberg
authors.forename: Bernard A
authors.initials: BA
authors.lastname: Prior
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D003001:Cloning, Molecular; D004098:Dihydroxyacetone / Q000378:metabolism; D005656:Fungal Proteins / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D005990:Glycerol / Q000378:metabolism; D008969:Molecular Sequence Data; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012965:Sodium Chloride; D014882:Water-Electrolyte Balance; D020068:Zygosaccharomyces / Q000737:chemistry / Q000235:genetics*
chemical_list: D005656:Fungal Proteins; D012965:Sodium Chloride; D000255:Adenosine Triphosphate; D017853:Phosphotransferases (Alcohol Group Acceptor); C023132:glycerone kinase; D004098:Dihydroxyacetone; D005990:Glycerol