Xylitol dehydrogenase from Candida tropicalis: molecular cloning of the gene and structural analysis of the protein

• Published in: Applied microbiology and biotechnology 2006-12, Vol.73 (3), p.631-639
• Main Authors: Lima, Luanne Helena Augusto, Pinheiro, Cristiano Guimarães do Amaral, Moraes, Lídia Maria Pepe de, Freitas, Sonia Maria de, Torres, Fernando Araripe Gonçalves
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Amino acids; Base Sequence; Binding Sites; Biological and medical sciences; Biotechnology; Candida tropicalis; Candida tropicalis - enzymology; Candida tropicalis - genetics; Cloning; Cloning, Molecular; D-Xylulose Reductase - chemistry; D-Xylulose Reductase - genetics; Dehydrogenase; Dehydrogenases; Enzymes; Ethanol; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation, Fungal; Genes, Fungal; Genetics; Medium-chain dehydrogenase family; Metabolism; Models, Molecular; Molecular modeling; Molecular Sequence Data; NAD - chemistry; protein structure; Protein Structure, Tertiary; Saccharomyces cerevisiae; Sequence Alignment; Structural analysis; Studies; Xylitol dehydrogenase; Yeast; Yeasts; Zinc - chemistry
• ISSN: 0175-7598; 1432-0614
• DOI: 10.1007/s00253-006-0525-0

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.