[Cloning and expression analysis of pathogenesis-related protein 1 gene of Panax notoginseng]

By reverse transcription-polymerase chain reaction (RT-PCR), an open reading frame of pathogenesis-related protein 1 (PR1) was isolated from Panax notoginseng and named as PnPR1. Molecular and bioinformatic analyses of PnPR1 revealed that an open reading frame of 501 bp was predicted to encode a 166-amino acid protein with a deduced molecular mass of 18.1 kD. Homology analysis showed that the deduced amino acid sequence of PR1 protein of Panax notoginseng had a high similarity with other higher plants had the same conservative structure domain of cysteine-rich secretory protein (CAP). The recombinant expressed plasmid pET28a(+)-PnPR1 was expressed in Escherichia coli BL21. The expression conditions were optimized by induction at different times, different temperatures, different IPTG concentrations and different giving times. The optimum expression condition was 0.4 mmol.L-1 IPTG at 28 degrees C for 20 h. The successful expression of PnPR1 provides some basis for protein purification and preparation of the monoclonal antibody.