Complementation of a pgk deletion mutation in Saccharomyces cerevisiae with expression of the phosphoglycerate-kinase gene from the hyperthermophilic Archaeon Sulfolobus solfataricus

Abstract

 The gene encoding phosphoglycerate kinase (PGK) from the Archaeon Sulfolobus solfataricus, an organism growing optimally at 87 °C, was inserted into a yeast expression vector under the control of the galactose-inducible GAL1 yeast promoter. This vector was then transformed into a pgk::TRP1 yeast mutant, a strain inhibited for growth on galactose or glucose due to its lack of PGK enzyme. Slow-growing transformants were obtained on galactose plates at 37 °C, but not 28 °C. These transformants contained low levels of transcripts of the heterologous gene and low amounts of thermostable PGK activity. Weak expression of the hyperthermophile gene in yeast, a mesophile, therefore enabled complementation of the yeast pgk defect at 37 °C but not at 28 °C.