Abstract: The hsp gene fragment was amplified by polymerase chain reaction (PCR) from the leaves of Sophora Flavescens Ait, and then it was successfully ligated to the prokaryotic expression vector pET22b(+) for protein expression. The expression of hsp was induced with different concentrations of IPTG at different temperature. The coding region of the hsp gene was 498 bp, encoding for a protein of 166 amino acids with an estimated molecular mass of 17.8 ku (HSP17.8). The physicochemical properties, phylogenetic tree, secondary structure and 3D model of HSP17.8 were analyzed by bioinformatics software. The results showed that HSP17.8 was a stable hydrophilic protein with multiple N-myristoylation sites, phosphorylation sites and N-glycosylation sites. The protein had the closest relationship with HSP from Lupinus angustifolius. The 3D structure of HSP17.8 folds into a helix-turn-helix motif on a five-stranded beta-sheet scaffold arranged in the order β1-α1-β2-α2-β3-α3-β4-α4-β5. The hsp17.8 was cloned from Sophorae flavescentis Ait and expressed in vitro for the first time. The study of physicochemical properties, phylogenetic relationships and structure characteristics of HSP17.8 provided a theoretical foundation for the further structural and functional researches of HSP17.8.

Key words:  stress proteins, polymerase chain reaction, bioinformatics