title: Xylitol dehydrogenase from Candida tropicalis: molecular cloning of the gene and structural analysis of the protein.
abstract: Yeasts can metabolize xylose by the action of two key enzymes: xylose reductase and xylitol dehydrogenase. In this work, we present data concerning the cloning of the XYL2 gene encoding xylitol dehydrogenase from the yeast Candida tropicalis. The gene is present as a single copy in the genome and is controlled at the transcriptional level by the presence of the inducer xylose. XYL2 was functionally tested by heterologous expression in Saccharomyces cerevisiae to develop a yeast strain capable of producing ethanol from xylose. Structural analysis of C. tropicalis xylitol dehydrogenase, Xyl2, suggests that it is a member of the medium-chain dehydrogenase (MDR) family. This is supported by the presence of the amino acid signature [GHE]xx[G]xxxxx[G]xx[V] in its primary sequence and a typical alcohol dehydrogenase Rossmann fold pattern composed by NAD(+) and zinc ion binding domains.
authors.affiliation: Departamento de Biologia Celular, Universidade de Brasília, Brasília DF 70910-900, Brazil.
authors.forename: Luanne Helena Augusto
authors.initials: LH
authors.lastname: Lima
authors.forename: Cristiano Guimarães do Amaral
authors.initials: CG
authors.lastname: Pinheiro
authors.forename: Lídia Maria Pepe
authors.initials: LM
authors.lastname: de Moraes
authors.forename: Sonia Maria
authors.initials: SM
authors.lastname: de Freitas
authors.forename: Fernando Araripe Gonçalves
authors.initials: FA
authors.lastname: Torres
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D041022:Candida tropicalis / Q000201:enzymology* / Q000235:genetics; D003001:Cloning, Molecular; D050542:D-Xylulose Reductase / Q000737:chemistry* / Q000235:genetics*; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009243:NAD / Q000737:chemistry; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment; D015032:Zinc / Q000737:chemistry
chemical_list: D009243:NAD; D050542:D-Xylulose Reductase; D015032:Zinc