Bl. Kelly et Ml. Greenberg, EXPRESSION IN YEAST OF AN ESCHERICHIA-COLI GENE ENCODING A PHOSPHOLIPID BIOSYNTHETIC ENZYME, Gene, 147(1), 1994, pp. 111-114
Cardiolipin (CL) is a structurally unique phospholipid having importan
t functional roles in both prokaryotic and eukaryotic cells. The genes
encoding CL biosynthetic enzymes have been identified and extensively
studied in Escherichia coli, and manipulation of CL biosynthesis in t
his organism has elucidated a great deal about CL function in prokaryo
tes. In contrast, little is known about CL biosynthesis or its regulat
ion in eukaryotic cells. We sought to determine whether we could utili
ze E. coli genes to manipulate expression of CL biosynthetic enzymes a
nd CL content in yeast. The E. coli pgsA gene encodes phosphatidylglyc
erophosphate synthase (PGPS), catalyzing the first step in the CL bios
ynthetic pathway. We constructed plasmids with pgsA under the control
of the yeast CUP1 promoter. Extracts of Saccharomyces cerevisiae cells
transformed with this plasmid contained high levels of E. coli PGPS a
ctivity. However, when compared to cells transformed with a control pl
asmid, pgsA-transfonmed cells did not exhibit differences in phospholi
pid composition. The most likely explanation is that the in vitro acti
vity of the E. coli pgsA product is not indicative of its activity in
vivo, due to mislocalization of the enzyme and/or inaccessibility of t
he enzyme to the substrates. To our knowledge, this is the first demon
stration of expression of a bacterial phospholipid biosynthetic enzyme
in yeast.