Cloning and characterization of the lactate-specific inducible geneKlCYB2, encoding the cytochromeb2 ofKluyveromyces lactis

✍ Scribed by Alberti, Adriana; Goffrini, Paola; Ferrero, Iliana; Lodi, Tiziana

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 182 KB
• Volume: 16
• Category: Article
• ISSN: 0749-503X
• DOI: 10.1002/(sici)1097-0061(200005)16:7<657::aid-yea560>3.0.co;2-#

✦ Synopsis

In yeast the utilization of lactate requires two enzymes, the D and L-lactate ferricytochrome c oxidoreductase (D and L-LCR), which stereospeci®cally oxidize D-and L-lactate to pyruvate. These enzymes are nuclearly encoded and localized in mitochondria. In the yeast Kluyveromyces lactis, a mutant devoid of D-and L-LCR activities and unable to grow on racemic lactate was isolated. Transformation of the mutant with a K. lactis genomic library allowed the isolation of the KlCYB2 gene, restoring the growth on lactate and the L-LCR activity. The KlCYB2 gene and its ¯anking regions were sequenced (Accession No. AJ243324; EMBL/GenBank databases). The deduced amino acid sequence is highly homologous to the corresponding Saccharomyces cerevisiae and Hansenula anomala protein sequences previously characterized. The homology is missed in the Nterminal region, corresponding to the presequence cleaved during import into mitochondria. Analysis of KlCYB2 gene expression indicated that, in contrast to S. cerevisiae, the major regulatory feature is induction by lactate.