COMPLEMENTARY DNAS ENCODING EUKARYOTIC-TYPE CYTIDINE-5'-DIPHOSPHATE-DIACYLGLYCEROL SYNTHASES OF 2 PLANT-SPECIES

Cytidine diphosphate (CDP)-diacylglycerol synthase (cytidine triphosph ate:phosphatidate cytidyltransferase, EC 2.7.7.41) catalyzes the forma tion of CDP-diacylglycerol, which is the precursor of phosphatidylinos itol, phosphatidylglycerol, and cardiolipin. We report the first cloni ng, to our knowledge, of two plant cDNAs, SfCDS1 and AfCDS1, coding fo r CDP-diacylglycerol synthases from potato (Solanum tuberosum) and Ara bidopsis thaliana, respectively. The two proteins belong to the eukary otic type of CDP-diacylglycerol synthases and contain eight predicted transmembrane-spanning domains. We analyzed gene expression in shoot a nd root tissues of potato plants and demonstrated enzyme activity by e xpression of N-terminally truncated, recombinant StCDS1 in Escherichia coli.