Lima Luanne Helena Augusto, Pinheiro Cristiano Guimarães do Amaral, de Moraes Lídia Maria Pepe, de Freitas Sonia Maria, Torres Fernando Araripe Gonçalves
Departamento de Biologia Celular, Universidade de Brasília, Brasília DF 70910-900, Brazil.
Appl Microbiol Biotechnol. 2006 Dec;73(3):631-9. doi: 10.1007/s00253-006-0525-0. Epub 2006 Aug 2.
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.
木糖还原酶和木糖醇脱氢酶。在本研究中，我们展示了从热带假丝酵母中克隆编码木糖醇脱氢酶的XYL2基因的数据。该基因在基因组中以单拷贝形式存在，并受诱导剂木糖的存在调控转录水平。通过在酿酒酵母中的异源表达对XYL2进行功能测试，以开发一种能够从木糖生产乙醇的酵母菌株。热带假丝酵母木糖醇脱氢酶Xyl2的结构分析表明，它是中链脱氢酶（MDR）家族的成员。其一级序列中存在氨基酸特征序列[GHE]xx[G]xxxxx[G]xx[V]以及由NAD(+)和锌离子结合域组成的典型醇脱氢酶罗斯曼折叠模式，支持了这一结论。
