Abstract: In this study, we cloned and characterized a geranylgeranyl pyrophosphate synthase(GGPS)gene from Ginkgo biloba Linn. The full-length cDNA sequence of GbGGPS was 1 641 bp containing an open reading frame(ORF)of 1 176 bp, which encoded a 391 amino acids with a predicted molecular mass of 42.51 ku and the theoretical isoelectric point(PI)of 5.98. GbGGPS was an intro-free gene, and its deduced polypeptide contained a chloroplast-targeting signal peptide of 79 amino acids in the N terminal. The secondary structure of GbGGPS was mainly composed of alpha helix and random coil. Comparative analysis showed that GbGGPS had a high similarity to other plant GGPS proteins, and contained all the five conserved domains and functional aspartate-rich motifs of the polyprenyl synthetase family. The homology-based structural modeling showed that GbGGPS has the typical structure of Menthax piperita GGPS. Phylogenetic tree revealed that GbGGPS, TcGGDS, PaGGDS5 and AgGGDS were assigned to the same clade.

Key words: ginkgolides, geranylgeranyl pyrophosphate synthase(GGPS), protein structure, bioinformatics analysis