Short Communication Cloning and Functional Expression of a Novel Geranylgeranyl Pyrophosphate Synthase Gene from Arabidopsis thaliana in Escherichia coli

A gene encoding a novel geranylgeranyl pyrophos-phate (GGPP) synthase from Arabidopsis thaliana has been identified and termed GGPS5. The gene has been se-quenced and expressed in Escherichia coli. The deduced amino acid sequence showed 64.5 % and 57.5 % identity with a putative GGPP synthase from Arabidopsis and Cap-sicum annuum, respectively. GGPP enzymatic activity was detected in E. coli cells expressing the GGPS5 gene in two different ways. One was the direct measurement of GGPP synthase activity in cell extracts and the other was the yellow color production of cells when the GGPS5 gene was co-expressed with crtB, crtl, crtX, crtY and crtZ genes de-rived from Erwinia uredovora. Key words: Arabidopsis thaliana — Carotenoid — crtE — GGPP synthase. The isoprenoid biosynthetic pathway is responsible for the synthesis of a variety of products including steroids, carotenoids, glycosyl carrier lipids, prenyl side-chain of quinones and prenyl proteins (Poulter and Rilling 1982, Clark 1992, Chappell 1995). Geranylgeranyl pyrophos-phate (GGPP) synthase is generally thought to be an impor-tant branch point enzyme for isoprenoid biosynthesis, since it catalyzes a farnesyl pyrophosphate (FPP) bran-ching reaction with the condensation of FPP and isopen-tenyl pyrophosphate (IPP) to produce C20 GGPP, which contains 4 isoprene units. GGPP plays different roles in various organisms. In plants and some bacteria, it is a